@article{CestnikMauRosenblum2022, author = {Cestnik, Rok and Mau, Erik T. K. and Rosenblum, Michael}, title = {Inferring oscillator's phase and amplitude response from a scalar signal exploiting test stimulation}, series = {New journal of physics : the open-access journal for physics}, volume = {24}, journal = {New journal of physics : the open-access journal for physics}, number = {12}, publisher = {Dt. Physikalische Ges., IOP}, address = {Bad Honnef, London}, issn = {1367-2630}, doi = {10.1088/1367-2630/aca70a}, pages = {27}, year = {2022}, abstract = {The phase sensitivity curve or phase response curve (PRC) quantifies the oscillator's reaction to stimulation at a specific phase and is a primary characteristic of a self-sustained oscillatory unit. Knowledge of this curve yields a phase dynamics description of the oscillator for arbitrary weak forcing. Similar, though much less studied characteristic, is the amplitude response that can be defined either using an ad hoc approach to amplitude estimation or via the isostable variables. Here, we discuss the problem of the phase and amplitude response inference from observations using test stimulation. Although PRC determination for noise-free neuronal-like oscillators perturbed by narrow pulses is a well-known task, the general case remains a challenging problem. Even more challenging is the inference of the amplitude response. This characteristic is crucial, e.g. for controlling the amplitude of the collective mode in a network of interacting units-a task relevant to neuroscience. Here, we compare the performance of different techniques suitable for inferring the phase and amplitude response, particularly with application to macroscopic oscillators. We suggest improvements to these techniques, e.g. demonstrating how to obtain the PRC in case of stimuli of arbitrary shape. Our main result is a novel technique denoted by IPID-1, based on the direct reconstruction of the Winfree equation and the analogous first-order equation for isostable dynamics. The technique works for signals with or without well-pronounced marker events and pulses of arbitrary shape; in particular, we consider charge-balanced pulses typical in neuroscience applications. Moreover, this technique is superior for noisy and high-dimensional systems. Additionally, we describe an error measure that can be computed solely from data and complements any inference technique.}, language = {en} } @article{DurandvandenBroekeLeCozannetetal.2022, author = {Durand, Gael and van den Broeke, Michiel R. and Le Cozannet, Goneri and Edwards, Tamsin L. and Holland, Paul R. and Jourdain, Nicolas C. and Marzeion, Ben and Mottram, Ruth and Nicholls, Robert J. and Pattyn, Frank and Paul, Frank and Slangen, Aimee B. A. and Winkelmann, Ricarda and Burgard, Clara and van Calcar, Caroline J. and Barre, Jean-Baptiste and Bataille, Amelie and Chapuis, Anne}, title = {Sea-Level rise: from global perspectives to local services}, series = {Frontiers in Marine Science}, volume = {8}, journal = {Frontiers in Marine Science}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {2296-7745}, doi = {10.3389/fmars.2021.709595}, pages = {8}, year = {2022}, abstract = {Coastal areas are highly diverse, ecologically rich, regions of key socio-economic activity, and are particularly sensitive to sea-level change. Over most of the 20th century, global mean sea level has risen mainly due to warming and subsequent expansion of the upper ocean layers as well as the melting of glaciers and ice caps. Over the last three decades, increased mass loss of the Greenland and Antarctic ice sheets has also started to contribute significantly to contemporary sea-level rise. The future mass loss of the two ice sheets, which combined represent a sea-level rise potential of similar to 65 m, constitutes the main source of uncertainty in long-term (centennial to millennial) sea-level rise projections. Improved knowledge of the magnitude and rate of future sea-level change is therefore of utmost importance. Moreover, sea level does not change uniformly across the globe and can differ greatly at both regional and local scales. The most appropriate and feasible sea level mitigation and adaptation measures in coastal regions strongly depend on local land use and associated risk aversion. Here, we advocate that addressing the problem of future sea-level rise and its impacts requires (i) bringing together a transdisciplinary scientific community, from climate and cryospheric scientists to coastal impact specialists, and (ii) interacting closely and iteratively with users and local stakeholders to co-design and co-build coastal climate services, including addressing the high-end risks.}, language = {en} } @article{KretzschmarAshbyFearonetal.2022, author = {Kretzschmar, Mirjam E. and Ashby, Ben and Fearon, Elizabeth and Overton, Christopher E. and Panovska-Griffiths, Jasmina and Pellis, Lorenzo and Quaife, Matthew and Rozhnova, Ganna and Scarabel, Francesca and Stage, Helena B. and Swallow, Ben and Thompson, Robin N. and Tildesley, Michael J. and Villela, Daniel Campos}, title = {Challenges for modelling interventions for future pandemics}, series = {Epidemics}, volume = {38}, journal = {Epidemics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1755-4365}, doi = {10.1016/j.epidem.2022.100546}, pages = {13}, year = {2022}, abstract = {Mathematical modelling and statistical inference provide a framework to evaluate different non-pharmaceutical and pharmaceutical interventions for the control of epidemics that has been widely used during the COVID-19 pandemic. In this paper, lessons learned from this and previous epidemics are used to highlight the challenges for future pandemic control. We consider the availability and use of data, as well as the need for correct parameterisation and calibration for different model frameworks. We discuss challenges that arise in describing and distinguishing between different interventions, within different modelling structures, and allowing both within and between host dynamics. We also highlight challenges in modelling the health economic and political aspects of interventions. Given the diversity of these challenges, a broad variety of interdisciplinary expertise is needed to address them, combining mathematical knowledge with biological and social insights, and including health economics and communication skills. Addressing these challenges for the future requires strong cross disciplinary collaboration together with close communication between scientists and policy makers.}, language = {en} } @article{AndersKhalatyanQueirozetal.2022, author = {Anders, Friedrich and Khalatyan, Arman and Queiroz, Anna B. A. and Chiappini, Cristina and Ard{\`e}vol, Judith and Casamiquela, Laia and Figueras, Francesca and Jim{\´e}nez-Arranz, {\´O}scar and Jordi, Carme and Monguio, Maria and Romero-G{\´o}mez, Merce and Altamirano, Diego and Antoja, Teresa and Assaad, R. and Cantat-Gaudin, Tristan and Castro-Ginard, Alfred and Enke, Harry and Girardi, L{\´e}o and Guiglion, Guillaume and Khan, Saniya and Luri, Xavier and Miglio, Andrea and Minchev, Ivan and Ramos, Pau and Santiago, Basillio Xavier and Steinmetz, Matthias}, title = {Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5}, series = {Astronomy and astrophysics}, volume = {658}, journal = {Astronomy and astrophysics}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0004-6361}, doi = {10.1051/0004-6361/202142369}, pages = {27}, year = {2022}, abstract = {We present a catalogue of 362 million stellar parameters, distances, and extinctions derived from Gaia's Early Data Release (EDR3) cross-matched with the photometric catalogues of Pan-STARRS1, SkyMapper, 2MASS, and All WISE. The higher precision of the Gaia EDR3 data, combined with the broad wavelength coverage of the additional photometric surveys and the new stellar-density priors of the StarHorse code, allows us to substantially improve the accuracy and precision over previous photo-astrometric stellar-parameter estimates. At magnitude G = 14 (17), our typical precisions amount to 3\% (15\%) in distance, 0.13 mag (0.15 mag) in V-band extinction, and 140 K (180 K) in effective temperature. Our results are validated by comparisons with open clusters, as well as with asteroseismic and spectroscopic measurements, indicating systematic errors smaller than the nominal uncertainties for the vast majority of objects. We also provide distance- and extinction-corrected colour-magnitude diagrams, extinction maps, and extensive stellar density maps that reveal detailed substructures in the Milky Way and beyond. The new density maps now probe a much greater volume, extending to regions beyond the Galactic bar and to Local Group galaxies, with a larger total number density. We publish our results through an ADQL query interface (gaia . aip . de) as well as via tables containing approximations of the full posterior distributions. Our multi-wavelength approach and the deep magnitude limit render our results useful also beyond the next Gaia release, DR3.}, language = {en} } @article{KelesMallonnKitzmannetal.2022, author = {Keles, Engin and Mallonn, Matthias and Kitzmann, Daniel and Poppenh{\"a}ger, Katja and Hoeijmakers, H. Jens and Ilyin, Ilya and Alexoudi, Xanthippi and Carroll, Thorsten A. and Alvarado-Gomez, Julian and Ketzer, Laura and Bonomo, Aldo S. and Borsa, Francesco and Gaudi, B. Scott and Henning, Thomas and Malavolta, Luca and Molaverdikhani, Karan and Nascimbeni, Valerio and Patience, Jennifer and Pino, Lorenzo and Scandariato, Gaetano and Schlawin, Everett and Shkolnik, Evgenya and Sicilia, Daniela and Sozzetti, Alessandro and Foster, Mary G. and Veillet, Christian and Wang, Ji and Yan, Fei and Strassmeier, Klaus G.}, title = {The PEPSI exoplanet transit survey (PETS) I: Investigating the presence of a silicate atmosphere on the super-earth 55 Cnc e}, series = {Monthly notices of the Royal Astronomical Society}, volume = {513}, journal = {Monthly notices of the Royal Astronomical Society}, number = {1}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stac810}, pages = {1544 -- 1556}, year = {2022}, abstract = {The study of exoplanets and especially their atmospheres can reveal key insights on their evolution by identifying specific atmospheric species. For such atmospheric investigations, high-resolution transmission spectroscopy has shown great success, especially for Jupiter-type planets. Towards the atmospheric characterization of smaller planets, the super-Earth exoplanet 55 Cnc e is one of the most promising terrestrial exoplanets studied to date. Here, we present a high-resolution spectroscopic transit observation of this planet, acquired with the PEPSI instrument at the Large Binocular Telescope. Assuming the presence of Earth-like crust species on the surface of 55 Cnc e, from which a possible silicate-vapor atmosphere could have originated, we search in its transmission spectrum for absorption of various atomic and ionized species such as Fe , Fe (+), Ca , Ca (+), Mg, and K , among others. Not finding absorption for any of the investigated species, we are able to set absorption limits with a median value of 1.9 x R-P. In conclusion, we do not find evidence of a widely extended silicate envelope on this super-Earth reaching several planetary radii.}, language = {en} } @article{KramerBouriaudFeindtetal.2022, author = {Kramer, Koen and Bouriaud, Laura and Feindt, Peter H. and van Wassenaer, Lan and Glanemann, Nicole and Hanewinkel, Marc and van der Heide, Martijn and Hengeveld, Geerten M. and Hoogstra, Marjanke and Ingram, Verina and Levermann, Anders and Lindner, Marcus and M{\´a}ty{\´a}s, Csaba and Mohren, Frits and Muys, Bart and Nabuurs, Gert-Jan and Palahi, Marc and Polman, Nico and Reyer, Christopher P. O. and Schulze, Ernst-Detlef and Seidl, Rupert and de Vries, Wim and Werners, Saskia E. and Winkel, Georg and Yousefpour, Rasoul}, title = {Perspective Roadmap to develop a stress test for forest ecosystem services supply}, series = {One Earth}, volume = {5}, journal = {One Earth}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2590-3330}, doi = {10.1016/j.oneear.2021.12.009}, pages = {25 -- 34}, year = {2022}, abstract = {Forests play a key role in a bio-based economy by providing renewable materials, mitigating climate change, and accommodating biodiversity. However, forests experience massive increases in stresses in their ecological and socioeconomic environments, threatening forest ecosystem services supply. Alleviating those stresses is hampered by conflicting and disconnected governance arrangements, competing interests and claims, and rapid changes in technology and social demands. Identifying which stresses threaten forest ecosystem services supply and which factors hamper their alleviation requires stakeholders' perceptions. Stakeholder-oriented stress tests for the supply of forest ecosystem services are therefore necessary but are not yet available. This perspective presents a roadmap to develop a stress test tailored to multiple stakeholders' needs and demands across spatial scales. We provide the Cascade and Resilience Rosetta, with accompanying performance- and resilience indicators, as tools to facilitate development of the stress test. The application of the stress test will facilitate the transition toward a bio-based economy in which healthy and diverse forests provide sustainable and resilient ecosystem services.}, language = {en} } @article{HempelSavenjieStolterfohtetal.2022, author = {Hempel, Hannes and Savenjie, Tom J. and Stolterfoht, Martin and Neu, Jens and Failla, Michele and Paingad, Vaisakh C. and Kužel, Petr and Heilweil, Edwin J. and Spies, Jacob A. and Schleuning, Markus and Zhao, Jiashang and Friedrich, Dennis and Schwarzburg, Klaus and Siebbeles, Laurens D. A. and D{\"o}rflinger, Patrick and Dyakonov, Vladimir and Katoh, Ryuzi and Hong, Min Ji and Labram, John G. and Monti, Maurizio and Butler-Caddle, Edward and Lloyd-Hughes, James and Taheri, Mohammad M. and Baxter, Jason B. and Magnanelli, Timothy J. and Luo, Simon and Cardon, Joseph M. and Ardo, Shane and Unold, Thomas}, title = {Predicting solar cell performance from terahertz and microwave spectroscopy}, series = {Advanced energy materials}, volume = {12}, journal = {Advanced energy materials}, number = {13}, publisher = {Wiley}, address = {Weinheim}, issn = {1614-6832}, doi = {10.1002/aenm.202102776}, pages = {16}, year = {2022}, abstract = {Mobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model the current-voltage characteristics of a solar cell from such measurements. To this end, the impact of measurement conditions, alternate interpretations, and experimental inter-laboratory variations are discussed using a (Cs,FA,MA)Pb(I,Br)(3) halide perovskite thin-film as a case study. At 1 sun equivalent excitation, neither transport nor recombination is significantly affected by exciton formation or trapping. Terahertz, microwave, and photoluminescence transients for the neat material yield consistent effective lifetimes implying a resistance-free JV-curve with a potential power conversion efficiency of 24.6 \%. For grainsizes above approximate to 20 nm, intra-grain charge transport is characterized by terahertz sum mobilities of approximate to 32 cm(2) V-1 s(-1). Drift-diffusion simulations indicate that these intra-grain mobilities can slightly reduce the fill factor of perovskite solar cells to 0.82, in accordance with the best-realized devices in the literature. Beyond perovskites, this work can guide a highly predictive characterization of any emerging semiconductor for photovoltaic or photoelectrochemical energy conversion. A best practice for the interpretation of terahertz and microwave measurements on photovoltaic materials is presented.}, language = {en} } @article{HuthPangTewsetal.2022, author = {Huth, Sabrina and Pang, Peter Tsun Ho and Tews, Ingo and Dietrich, Tim and Le F{\`e}vre, Arnaud and Schwenk, Achim and Trautmann, Wolfgang and Agarwal, Kshitij and Bulla, Mattia and Coughlin, Michael W. and Van den Broeck, Chris}, title = {Constraining neutron-star matter with microscopic and macroscopic collisions}, series = {Nature : the international weekly journal of science}, volume = {606}, journal = {Nature : the international weekly journal of science}, number = {7913}, publisher = {Nature Publ. Group}, address = {London [u.a.]}, issn = {0028-0836}, doi = {10.1038/s41586-022-04750-w}, pages = {276 -- 295}, year = {2022}, abstract = {Interpreting high-energy, astrophysical phenomena, such as supernova explosions or neutron-star collisions, requires a robust understanding of matter at supranuclear densities. However, our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, dense matter is not probed only in astrophysical observations, but also in terrestrial heavy-ion collision experiments. Here we use Bayesian inference to combine data from astrophysical multi-messenger observations of neutron stars(1-9) and from heavy-ion collisions of gold nuclei at relativistic energies(10,11) with microscopic nuclear theory calculations(12-17) to improve our understanding of dense matter. We find that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent observations by the Neutron Star Interior Composition Explorer mission(5-8,18). Our findings show that constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. This work combines nuclear theory, nuclear experiment and astrophysical observations, and shows how joint analyses can shed light on the properties of neutron-rich supranuclear matter over the density range probed in neutron stars.}, language = {en} } @article{PetrovSingerCoughlinetal.2022, author = {Petrov, Polina and Singer, Leo P. and Coughlin, Michael W. and Kumar, Vishwesh and Almualla, Mouza and Anand, Shreya and Bulla, Mattia and Dietrich, Tim and Foucart, Francois and Guessoum, Nidhal}, title = {Data-driven expectations for electromagnetic counterpart searches based on LIGO/Virgo public alerts}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics; part 1}, volume = {924}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics; part 1}, number = {2}, publisher = {Institute of Physics Publ.}, address = {London}, issn = {1538-4357}, doi = {10.3847/1538-4357/ac366d}, pages = {10}, year = {2022}, abstract = {Searches for electromagnetic counterparts of gravitational-wave signals have redoubled since the first detection in 2017 of a binary neutron star merger with a gamma-ray burst, optical/infrared kilonova, and panchromatic afterglow. Yet, one LIGO/Virgo observing run later, there has not yet been a second, secure identification of an electromagnetic counterpart. This is not surprising given that the localization uncertainties of events in LIGO and Virgo's third observing run, O3, were much larger than predicted. We explain this by showing that improvements in data analysis that now allow LIGO/Virgo to detect weaker and hence more poorly localized events have increased the overall number of detections, of which well-localized, gold-plated events make up a smaller proportion overall. We present simulations of the next two LIGO/Virgo/KAGRA observing runs, O4 and O5, that are grounded in the statistics of O3 public alerts. To illustrate the significant impact that the updated predictions can have, we study the follow-up strategy for the Zwicky Transient Facility. Realistic and timely forecasting of gravitational-wave localization accuracy is paramount given the large commitments of telescope time and the need to prioritize which events are followed up. We include a data release of our simulated localizations as a public proposal planning resource for astronomers.}, language = {en} } @article{KollmannRoussosClarketal.2022, author = {Kollmann, Peter and Roussos, Elias and Clark, George and Cooper, John F. and Sturner, Steven J. and Kotova, Anna and Regoli, Leonardo and Shprits, Yuri and Aseev, Nikita and Krupp, Norbert}, title = {Spectra of Saturn's proton belts revealed}, series = {Icarus}, volume = {376}, journal = {Icarus}, publisher = {Elsevier}, address = {San Diego}, issn = {0019-1035}, doi = {10.1016/j.icarus.2021.114795}, pages = {17}, year = {2022}, abstract = {Saturn is permanently surrounded by 6 discrete proton radiation belts that are rigidly separated by the orbits of its inner moons and dense rings. These radiation belts are ideal environments to study the details of radial diffusion and the CRAND source process, yet progress has been hindered by the fact that the energy spectra are not known with certainty: Reanalysis of the response functions of the LEMMS instrument on-board the Cassini orbiter has shown that measurements of less than or similar to 10 MeV protons may be easily contaminated by greater than or similar to 10 MeV protons and that many available measurements characterize a very broad energy range, so that the calculation of an energy-resolved spectrum is not as straightforward as previously assumed. Here we use forward modeling of the measurements based on the instrument response and combine this technique where useful with numerical modeling of the proton belt physics in order to determine Saturn's spectra with higher certainty. We find significant proton intensities up to approximate to 1 GeV. While earlier studies reported on proton spectra roughly following a power law with exponent approximate to -2, our more advanced analysis shows harder spectra with exponent approximate to -1. The observed spectra provide independent confirmation that Saturn's proton belts are sourced by CRAND and are consistent with the provided protons being subsequently cooled in the tenuous gas originating from Saturn or Enceladus. The intensities at Saturn are found to be lower than at Jupiter and Earth, which is also consistent with the source of Saturn being exclusively CRAND, while the other planets can draw from additional processes. Our new spectra can be used in the future to further our understanding of Saturn's proton belts and the respective physical processes that occur at other magnetized planets in general. Also, the spectra have applications for several topics of planetary science, such as space weathering of Saturn's moons and rings, and can be useful to constrain properties of the main rings through their production of secondary particles.}, language = {en} } @article{SchaererIzotovWorsecketal.2022, author = {Schaerer, Daniel and Izotov, Yuri I. and Worseck, G{\´a}bor and Berg, Danielle and Chisholm, John and Jaskot, Anne and Nakajima, Kimihiko and Ravindranath, Swara and Thuan, Trinh X. and Verhamme, Anne}, title = {Strong Lyman continuum emitting galaxies show intense C IV λ 1550 emission}, series = {Astronomy and astrophysics}, volume = {658}, journal = {Astronomy and astrophysics}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0004-6361}, doi = {10.1051/0004-6361/202243149}, pages = {6}, year = {2022}, abstract = {Using the Space Telescope Imaging Spectrograph, we have obtained ultraviolet spectra from similar to 1200 to 2000 angstrom of known Lyman continuum (LyC) emitting galaxies at low redshift (z similar to 0.3-0.4) with varying absolute LyC escape fractions ( f(esc) similar to 0.01-0.72). Our observations include in particular the galaxy J1243+4646, which has the highest known LyC escape fraction at low redshift. While all galaxies are known Lyman alpha emitters, we consistently detect an inventory of additional emission lines, including C IV lambda 1550, He II lambda 1640, O III] lambda 1666, and C III] lambda 1909, whose origin is presumably essentially nebular. C IV lambda 1550 emission is detected above 4 sigma in six out of eight galaxies, with equivalent widths of EW(C IV) = 12-15 angstrom for two galaxies, which exceeds the previously reported maximum emission in low-z star-forming galaxies. We detect C IV lambda 1550 emission in all LyC emitters with escape fractions f(esc) > 0.1 and find a tentative increase in the flux ratio C IV lambda 1550 /C III] lambda 1909 with f(esc). Based on the data, we propose a new criterion to select and classify strong leakers (galaxies with f(esc) > 0.1): C IV lambda 1550 /C III] lambda 1909 greater than or similar to 0.75. Finally, we also find He II lambda 1640 emission in all the strong leakers with equivalent widths from 3 to 8 angstrom rest frame. These are among the highest values observed in star-forming galaxies and are primarily due to a high rate of ionizing photon production. The nebular He II lambda 1640 emission of the strong LyC emitters does not require harder ionizing spectra at >54 eV compared to those of typical star-forming galaxies at similarly low metallicity.}, language = {en} } @article{CiarnielloFulleRaponietal.2022, author = {Ciarniello, Mauro and Fulle, Marco and Raponi, Andrea and Filacchione, Gianrico and Capaccioni, Fabrizio and Rotundi, Alessandra and Rinaldi, Giovanna and Formisano, Michelangelo and Magni, Gianfranco and Tosi, Federico and De Sanctis, Maria Cristina and Capria, Maria Teresa and Longobardo, Andrea and Beck, Pierre and Fornasier, Sonia and Kappel, David and Mennella, Vito and Mottola, Stefano and Rousseau, Batiste and Arnold, Gabriele}, title = {Macro and micro structures of pebble-made cometary nuclei reconciled by seasonal evolution}, series = {Nature astronomy}, volume = {6}, journal = {Nature astronomy}, number = {5}, publisher = {Nature Research}, address = {Berlin}, issn = {2397-3366}, doi = {10.1038/s41550-022-01625-y}, pages = {546 -- 553}, year = {2022}, abstract = {Comets evolve due to sublimation of ices embedded inside porous dust, triggering dust emission (that is, erosion) followed by mass loss, mass redistribution and surface modifications. Surface changes were revealed by the Deep Impact and Stardust NExT missions for comet 9P/Tempel 1 (ref.(1)), and a full inventory of the processes modifying cometary nuclei was provided by Rosetta while it escorted comet 67P/Churyumov-Gerasimenko for approximately two years(2-4). Such observations also showed puzzling water-ice-rich spots that stood out as patches optically brighter and spectrally bluer than the average cometary surfaces(5-9). These are up to tens of metres large and indicate macroscopic compositional dishomogeneities apparently in contrast with the structural homogeneity above centimetre scales of pebble-made nuclei(10). Here we show that the occurrence of blue patches determines the seasonal variability of the nucleus colour(4,11,12) and gives insight into the internal structure of comets. We define a new model that links the centimetre-sized pebbles composing the nucleus(10) and driving cometary activity(13,14) to metre-sized water-ice-enriched blocks embedded in a drier matrix. The emergence of blue patches is due to the matrix erosion driven by CO2-ice sublimation that exposes the water-ice-enriched blocks, which in turn are eroded by water-ice sublimation when exposed to sunlight. Our model explains the observed seasonal evolution of the nucleus and reconciles the available data at micro (sub-centimetre) and macro (metre) scales.}, language = {en} } @article{KupferBauervanRoesteletal.2022, author = {Kupfer, Thomas and Bauer, Evan B. and van Roestel, Jan and Bellm, Eric C. and Bildsten, Lars and Fuller, Jim and Prince, Thomas A. and Heber, Ulrich and Geier, Stephan and Green, Matthew J. and Kulkarni, Shrinivas R. and Bloemen, Steven and Laher, Russ R. and Rusholme, Ben and Schneider, David}, title = {Discovery of a Double-detonation Thermonuclear Supernova Progenitor}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, volume = {925}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {2041-8205}, doi = {10.3847/2041-8213/ac48f1}, pages = {10}, year = {2022}, abstract = {We present the discovery of a new double-detonation progenitor system consisting of a hot subdwarf B (sdB) binary with a white dwarf companion with a P (orb) = 76.34179(2) minutes orbital period. Spectroscopic observations are consistent with an sdB star during helium core burning residing on the extreme horizontal branch. Chimera light curves are dominated by ellipsoidal deformation of the sdB star and a weak eclipse of the companion white dwarf. Combining spectroscopic and light curve fits, we find a low-mass sdB star, M (sdB) = 0.383 +/- 0.028 M (circle dot) with a massive white dwarf companion, M (WD) = 0.725 +/- 0.026 M (circle dot). From the eclipses we find a blackbody temperature for the white dwarf of 26,800 K resulting in a cooling age of approximate to 25 Myr whereas our MESA model predicts an sdB age of approximate to 170 Myr. We conclude that the sdB formed first through stable mass transfer followed by a common envelope which led to the formation of the white dwarf companion approximate to 25 Myr ago. Using the MESA stellar evolutionary code we find that the sdB star will start mass transfer in approximate to 6 Myr and in approximate to 60 Myr the white dwarf will reach a total mass of 0.92 M (circle dot) with a thick helium layer of 0.17 M (circle dot). This will lead to a detonation that will likely destroy the white dwarf in a peculiar thermonuclear supernova. PTF1 J2238+7430 is only the second confirmed candidate for a double-detonation thermonuclear supernova. Using both systems we estimate that at least approximate to 1\% of white dwarf thermonuclear supernovae originate from sdB+WD binaries with thick helium layers, consistent with the small number of observed peculiar thermonuclear explosions.}, language = {en} } @article{SchwopePiresKurpasetal.2022, author = {Schwope, Axel and Pires, Adriana M. and Kurpas, Jan and Doroshenko, Victor and Suleimanov, Valery F. and Freyberg, Michael and Becker, Werner and Dennerl, Konrad and Haberl, Frank and Lamer, Georg and Maitra, Chandreyee and Potekhin, Alexander Y. and Ramos-Ceja, Miriam E. and Santangelo, Andrea and Traulsen, Iris and Werner, Klaus}, title = {Phase-resolved X-ray spectroscopy of PSR B0656+14 with SRG/eROSITA and XMM-Newton}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {661}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0004-6361}, doi = {10.1051/0004-6361/202141105}, pages = {21}, year = {2022}, abstract = {We present a detailed spectroscopic and timing analysis of X-ray observations of the bright pulsar PSR B0656+14. The observations were obtained simultaneously with eROSITA and XMM-Newton during the calibration and performance verification phase of the Spektrum-Roentgen-Gamma mission (SRG). The analysis of the 100 ks deep observation of eROSITA is supported by archival observations of the source, including XMM-Newton, NuSTAR, and NICER. Using XMM-Newton and NICER, we first established an X-ray ephemeris for the time interval 2015 to 2020, which connects all X-ray observations in this period without cycle count alias and phase shifts. The mean eROSITA spectrum clearly reveals an absorption feature originating from the star at 570 eV with a Gaussian sigma of about 70 eV that was tentatively identified in a previous long XMM-Newton observation. A second previously discussed absorption feature occurs at 260-265 eV and is described here as an absorption edge. It could be of atmospheric or of instrumental origin. These absorption features are superposed on various emission components that are phenomenologically described here as the sum of hot (120 eV) and cold (65 eV) blackbody components, both of photospheric origin, and a power law with photon index Gamma = 2 from the magnetosphere. We created energy-dependent light curves and phase-resolved spectra with a high signal-to-noise ratio. The phase-resolved spectroscopy reveals that the Gaussian absorption line at 570 eV is clearly present throughout similar to 60\% of the spin cycle, but it is otherwise undetected. Likewise, its parameters were found to be dependent on phase. The visibility of the line strength coincides in phase with the maximum flux of the hot blackbody. If the line originates from the stellar surface, it nevertheless likely originates from a different location than the hot polar cap. We also present three families of model atmospheres: a magnetized atmosphere, a condensed surface, and a mixed model. They were applied to the mean observed spectrum, whose continuum fit the observed data well. The atmosphere model, however, predicts distances that are too short. For the mixed model, the Gaussian absorption may be interpreted as proton cyclotron absorption in a field as high as 10(14) G, which is significantly higher than the field derived from the moderate observed spin-down.}, language = {en} } @article{WarbyZuZeiskeetal.2022, author = {Warby, Jonathan and Zu, Fengshuo and Zeiske, Stefan and Gutierrez-Partida, Emilio and Frohloff, Lennart and Kahmann, Simon and Frohna, Kyle and Mosconi, Edoardo and Radicchi, Eros and Lang, Felix and Shah, Sahil and Pena-Camargo, Francisco and Hempel, Hannes and Unold, Thomas and Koch, Norbert and Armin, Ardalan and De Angelis, Filippo and Stranks, Samuel D. and Neher, Dieter and Stolterfoht, Martin}, title = {Understanding performance limiting interfacial recombination in pin Perovskite solar cells}, series = {Advanced energy materials}, volume = {12}, journal = {Advanced energy materials}, number = {12}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1614-6832}, doi = {10.1002/aenm.202103567}, pages = {10}, year = {2022}, abstract = {Perovskite semiconductors are an attractive option to overcome the limitations of established silicon based photovoltaic (PV) technologies due to their exceptional opto-electronic properties and their successful integration into multijunction cells. However, the performance of single- and multijunction cells is largely limited by significant nonradiative recombination at the perovskite/organic electron transport layer junctions. In this work, the cause of interfacial recombination at the perovskite/C-60 interface is revealed via a combination of photoluminescence, photoelectron spectroscopy, and first-principle numerical simulations. It is found that the most significant contribution to the total C-60-induced recombination loss occurs within the first monolayer of C-60, rather than in the bulk of C-60 or at the perovskite surface. The experiments show that the C-60 molecules act as deep trap states when in direct contact with the perovskite. It is further demonstrated that by reducing the surface coverage of C-60, the radiative efficiency of the bare perovskite layer can be retained. The findings of this work pave the way toward overcoming one of the most critical remaining performance losses in perovskite solar cells.}, language = {en} } @article{HerbstBaalmannBykovetal.2022, author = {Herbst, Konstantin and Baalmann, Lennart R. and Bykov, Andrei and Engelbrecht, N. Eugene and Ferreira, Stefan E. S. and Izmodenov, Vladislav V. and Korolkov, Sergey D. and Levenfish, Ksenia P. and Linsky, Jeffrey L. and Meyer, Dominique M. -A. and Scherer, Klaus and Strauss, R. Du Toit}, title = {Astrospheres of planet-hosting cool stars and beyond when modeling meets observations}, series = {Space science reviews}, volume = {218}, journal = {Space science reviews}, number = {4}, publisher = {Springer Nature}, address = {Dordrecht}, issn = {0038-6308}, doi = {10.1007/s11214-022-00894-3}, pages = {46}, year = {2022}, abstract = {Thanks to dedicated long-term missions like Voyager and GOES over the past 50 years, much insight has been gained on the activity of our Sun, the solar wind, its interaction with the interstellar medium, and, thus, about the formation, the evolution, and the structure of the heliosphere. Additionally, with the help of multi-wavelength observations by the Hubble Space Telescope, Kepler, and TESS, we not only were able to detect a variety of extrasolar planets and exomoons but also to study the characteristics of their host stars, and thus became aware that other stars drive bow shocks and astrospheres. Although features like, e.g., stellar winds, could not be measured directly, over the past years several techniques have been developed allowing us to indirectly derive properties like stellar mass-loss rates and stellar wind speeds, information that can be used as direct input to existing astrospheric modeling codes. In this review, the astrospheric modeling efforts of various stars will be presented. Starting with the heliosphere as a benchmark of astrospheric studies, investigating the paleo-heliospheric changes and the Balmer H alpha projections to 1 pc, we investigate the surroundings of cool and hot stars, but also of more exotic objects like neutron stars. While pulsar wind nebulae (PWNs) might be a source of high-energy galactic cosmic rays (GCRs), the astrospheric environments of cool and hot stars form a natural shield against GCRs. Their modulation within these astrospheres, and the possible impact of turbulence, are also addressed. This review shows that all of the presented modeling efforts are in excellent agreement with currently available observations.}, language = {en} } @article{OranWeissSantacruzPichetal.2022, author = {Oran, Rona and Weiss, Benjamin P. and Santacruz-Pich, Maria De Soria and Jun, Insoo and Lawrence, David J. and Polanskey, Carol A. and Ratliff, J. Martin and Raymond, Carol A. and Ream, Jodie B. and Russell, Christopher T. and Shprits, Yuri and Zuber, Maria T. and Elkins-Tanton, Linda T.}, title = {Maximum energies of trapped particles around magnetized planets and small bodies}, series = {Geophysical research letters}, volume = {49}, journal = {Geophysical research letters}, number = {13}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0094-8276}, doi = {10.1029/2021GL097014}, pages = {11}, year = {2022}, abstract = {Energetic charged particles trapped in planetary radiation belts are hazardous to spacecraft. Planned missions to iron-rich asteroids with possible strong remanent magnetic fields require an assessment of trapped particles energies. Using laboratory measurements of iron meteorites, we estimate the largest possible asteroid magnetic moment. Although weak compared to moments of planetary dynamos, the small body size may yield strong surface fields. We use hybrid simulations to confirm the formation of a magnetosphere with an extended quasi-dipolar region. However, the short length scale of the field implies that energetic particle motion would be nonadiabatic, making existing radiation belt theories not applicable. Our idealized particle simulations demonstrate that chaotic motions lead to particle loss at lower energies than those predicted by adiabatic theory, which may explain the energies of transiently trapped particles observed at Mercury, Ganymede, and Earth. However, even the most magnetized asteroids are unlikely to stably trap hazardous particles.}, language = {en} } @article{AguileraDenaLangerAntoniadisetal.2022, author = {Aguilera-Dena, David R. and Langer, Norbert and Antoniadis, John and Pauli, Daniel and Dessart, Luc and Vigna-G{\´o}mez, Alejandro and Gr{\"a}fener, G{\"o}tz and Yoon, Sung-Chul}, title = {Stripped-envelope stars in different metallicity environments: I. Evolutionary phases, classification, and populations}, series = {Astronomy and astrophysics}, volume = {661}, journal = {Astronomy and astrophysics}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0004-6361}, doi = {10.1051/0004-6361/202142895}, pages = {20}, year = {2022}, abstract = {Massive stars that become stripped of their hydrogen envelope through binary interaction or winds can be observed either as Wolf-Rayet stars, if they have optically thick winds, or as transparent-wind stripped-envelope stars. We approximate their evolution through evolutionary models of single helium stars, and compute detailed model grids in the initial mass range 1.5-70 M. for metallicities between 0.01 and 0.04, from core helium ignition until core collapse. Throughout their lifetimes some stellar models expose the ash of helium burning. We propose that models that have nitrogen-rich envelopes are candidate WN stars, while models with a carbon-rich surface are candidate WC stars during core helium burning, and WO stars afterwards. We measure the metallicity dependence of the total lifetimes of our models and the duration of their evolutionary phases. We propose an analytic estimate of the wind's optical depth to distinguish models of Wolf-Rayet stars from transparent-wind stripped-envelope stars, and find that the luminosity ranges at which WN-, WC-, and WO-type stars can exist is a strong function of metallicity. We find that all carbon-rich models produced in our grids have optically thick winds and match the luminosity distribution of observed populations. We construct population models and predict the numbers of transparent-wind stripped-envelope stars and Wolf-Rayet stars, and derive their number ratios at different metallicities. We find that as metallicity increases, the number of transparent-wind stripped-envelope stars decreases and the number of Wolf-Rayet stars increases. At high metallicities WC- and WO-type stars become more common. We apply our population models to nearby galaxies, and find that populations are more sensitive to the transition luminosity between Wolf-Rayet stars and transparent-wind helium stars than to the metallicity-dependent mass loss rates.}, language = {en} } @article{MarinBeloquiZhangGuoetal.2022, author = {Marin-Beloqui, Jose and Zhang, Guanran and Guo, Junjun and Shaikh, Jordan and Wohrer, Thibaut and Hosseini, Seyed Mehrdad and Sun, Bowen and Shipp, James and Auty, Alexander J. and Chekulaev, Dimitri and Ye, Jun and Chin, Yi-Chun and Sullivan, Michael B. and Mozer, Attila J. and Kim, Ji-Seon and Shoaee, Safa and Clarke, Tracey M.}, title = {Insight into the origin of trapping in polymer/fullerene blends with a systematic alteration of the fullerene to higher adducts}, series = {Journal of physical chemistry C}, volume = {126}, journal = {Journal of physical chemistry C}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.1c10378}, pages = {2708 -- 2719}, year = {2022}, abstract = {The bimolecular recombination characteristics of conjugated polymer poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,5-bis 3-tetradecylthiophen-2-y1 thiazolo 5,4-d thiazole)-2,5diy1] (PDTSiTTz) blended with the fullerene series PC60BM, ICMA, ICBA, and ICTA have been investigated using microsecond and femtosecond transient absorption spectroscopy, in conjunction with electroluminescence measurements and ambient photoemission spectroscopy. The non-Langevin polymer PDTSiTTz allows an inspection of intrinsic bimolecular recombination rates uninhibited by diffusion, while the low oscillator strengths of fullerenes allow polymer features to dominate, and we compare our results to those of the well-known polymer Si-PCPDTBT. Using mu s-TAS, we have shown that the trap -limited decay dynamics of the PDTSiTTz polaron becomes progressively slower across the fullerene series, while those of Si-PCPDTBT are invariant. Electroluminescence measurements showed an unusual double peak in pristine PDTSiTTz, attributed to a low energy intragap charge transfer state, likely interchain in nature. Furthermore, while the pristine PDTSiTTz showed a broad, low-intensity density of states, the ICBA and ICTA blends presented a virtually identical DOS to Si-PCPDTBT and its blends. This has been attributed to a shift from a delocalized, interchain highest occupied molecular orbital (HOMO) in the pristine material to a dithienosilole-centered HOMO in the blends, likely a result of the bulky fullerenes increasing interchain separation. This HOMO localization had a side effect of progressively shifting the polymer HOMO to shallower energies, which was correlated with the observed decrease in bimolecular recombination rate and increased "trap" depth. However, since the density of tail states remained the same, this suggests that the traditional viewpoint of "trapping" being dominated by tail states may not encompass the full picture and that the breadth of the DOS may also have a strong influence on bimolecular recombination.}, language = {en} } @article{IzotovChisholmWorsecketal.2022, author = {Izotov, Yuri I. and Chisholm, John and Worseck, G{\´a}bor and Guseva, Natalia G. and Schaerer, Daniel and Prochaska, Jason Xavier}, title = {Lyman alpha and Lyman continuum emission of Mg II-selected star-forming galaxies}, series = {Monthly notices of the Royal Astronomical Society}, volume = {515}, journal = {Monthly notices of the Royal Astronomical Society}, number = {2}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stac1899}, pages = {2864 -- 2881}, year = {2022}, abstract = {We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of seven compact low-mass star-forming galaxies at redshifts, z, in the range 0.3161-0.4276, with various O3Mg2 = [O III] lambda 5007/Mg II lambda 2796+2803 and Mg-2 = Mg II lambda 2796/Mg II lambda 2803 emission-line ratios. We aim to study the dependence of leaking Lyman continuum (LyC) emission on the characteristics of Mg ii emission together with the dependencies on other indirect indicators of escaping ionizing radiation. LyC emission with escape fractions f(esc)(LyC) = 3.1-4.6 per cent is detected in four galaxies, whereas only 1 sigma upper limits of f(esc)(LyC) in the remaining three galaxies were derived. A strong narrow Ly alpha emission line with two peaks separated by V-sep similar to 298-592 km s(-1) was observed in four galaxies with detected LyC emission and very weak Ly alpha emission is observed in galaxies with LyC non-detections. Our new data confirm the tight anticorrelation between f(esc)(LyC) and V-sep found for previous low-redshift galaxy samples. V-sep remains the best indirect indicator of LyC leakage among all considered indicators. It is found that escaping LyC emission is detected predominantly in galaxies with Mg-2 greater than or similar to 1.3. A tendency of an increase of f(esc)(LyC) with increasing of both the O3Mg2 and Mg-2 is possibly present. However, there is substantial scatter in these relations not allowing their use for reliable prediction of f(esc)(LyC).}, language = {en} } @article{BrinkmannBeckerZimmermannetal.2022, author = {Brinkmann, Kai Oliver and Becker, Tim and Zimmermann, Florian and Kreusel, Cedric and Gahlmann, Tobias and Theisen, Manuel and Haeger, Tobias and Olthof, Selina and T{\"u}ckmantel, Christian and G{\"u}nster, M. and Maschwitz, Timo and G{\"o}belsmann, Fabian and Koch, Christine and Hertel, Dirk and Caprioglio, Pietro and Pe{\~n}a-Camargo, Francisco and Perdig{\´o}n-Toro, Lorena and Al-Ashouri, Amran and Merten, Lena and Hinderhofer, Alexander and Gomell, Leonie and Zhang, Siyuan and Schreiber, Frank and Albrecht, Steve and Meerholz, Klaus and Neher, Dieter and Stolterfoht, Martin and Riedl, Thomas}, title = {Perovskite-organic tandem solar cells with indium oxide interconnect}, series = {Nature}, volume = {604}, journal = {Nature}, number = {7905}, publisher = {Nature Research}, address = {Berlin}, issn = {0028-0836}, doi = {10.1038/s41586-022-04455-0}, pages = {280 -- 286}, year = {2022}, abstract = {Multijunction solar cells can overcome the fundamental efficiency limits of single-junction devices. The bandgap tunability of metal halide perovskite solar cells renders them attractive for multijunction architectures(1). Combinations with silicon and copper indium gallium selenide (CIGS), as well as all-perovskite tandem cells, have been reported(2-5). Meanwhile, narrow-gap non-fullerene acceptors have unlocked skyrocketing efficiencies for organic solar cells(6,7). Organic and perovskite semiconductors are an attractive combination, sharing similar processing technologies. Currently, perovskite-organic tandems show subpar efficiencies and are limited by the low open-circuit voltage (V-oc) of wide-gap perovskite cells(8) and losses introduced by the interconnect between the subcells(9,10). Here we demonstrate perovskite-organic tandem cells with an efficiency of 24.0 per cent (certified 23.1 per cent) and a high V-oc of 2.15 volts. Optimized charge extraction layers afford perovskite subcells with an outstanding combination of high V-oc and fill factor. The organic subcells provide a high external quantum efficiency in the near-infrared and, in contrast to paradigmatic concerns about limited photostability of non-fullerene cells(11), show an outstanding operational stability if excitons are predominantly generated on the non-fullerene acceptor, which is the case in our tandems. The subcells are connected by an ultrathin (approximately 1.5 nanometres) metal-like indium oxide layer with unprecedented low optical/electrical losses. This work sets a milestone for perovskite-organic tandems, which outperform the best p-i-n perovskite single junctions(12) and are on a par with perovskite-CIGS and all-perovskite multijunctions(13).}, language = {en} } @article{ZapataArteagaMarinaZuoetal.2022, author = {Zapata-Arteaga, Osnat and Marina, Sara and Zuo, Guangzheng and Xu, Kai and D{\"o}rling, Bernhard and Alberto P{\´e}rez, Luis and Sebasti{\´a}n Reparaz, Juan and Mart{\´i}n, Jaime and Kemerink, Martijn and Campoy-Quiles, Mariano}, title = {Design rules for polymer blends with high thermoelectric performance}, series = {Advanced energy materials}, volume = {12}, journal = {Advanced energy materials}, number = {19}, publisher = {Wiley}, address = {Weinheim}, issn = {1614-6832}, doi = {10.1002/aenm.202104076}, pages = {11}, year = {2022}, abstract = {A combinatorial study of the effect of in-mixing of various guests on the thermoelectric properties of the host workhorse polymer poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT) is presented. Specifically, the composition and thickness for doped films of PBTTT blended with different polymers are varied. Some blends at guest weight fractions around 10-15\% exhibit up to a fivefold increase in power factor compared to the reference material, leading to zT values around 0.1. Spectroscopic analysis of the charge-transfer species, structural characterization using grazing-incidence wide-angle X-ray scattering, differential scanning calorimetry, Raman, and atomic force microscopy, and Monte Carlo simulations are employed to determine that the key to improved performance is for the guest to promote long-range electrical connectivity and low disorder, together with similar highest occupied molecular orbital levels for both materials in order to ensure electronic connectivity are combined.}, language = {en} } @article{NiederhoferCioniSchmidtetal.2022, author = {Niederhofer, Florian and Cioni, Maria-Rosa L. and Schmidt, Thomas and Bekki, Kenji and de Grijs, Richard and Ivanov, Valentin D. and Oliveira, Joana M. and Ripepi, Vincenzo and Subramanian, Smitha and van Loon, Jacco Th}, title = {The VMC survey - XLVI. Stellar proper motions in the centre of the Large Magellanic Cloud}, series = {Monthly notices of the Royal Astronomical Society}, volume = {512}, journal = {Monthly notices of the Royal Astronomical Society}, number = {4}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stac712}, pages = {5423 -- 5439}, year = {2022}, abstract = {We present proper motion (PM) measurements within the central region of the Large Magellanic Cloud (LMC), using near-infrared data from the VISTA survey of the Magellanic Cloud system (VMC). This work encompasses 18 VMC tiles covering a total sky area of similar to 28 deg(2). We computed absolute stellar PMs from multiepoch observations in the K-s filter over time baselines between similar to 12 and 47 months. Our final catalogue contains similar to 6322 000 likely LMC member stars with derived PMs. We employed a simple flat-rotating disc model to analyse and interpret the PM data. We found a stellar centre of rotation (alpha(0) = 79.95 degrees(+0.22)(-0.23), delta(0) = -69.31 degrees(+0.12)(-0.11)) that is in agreement with that resulting from Hubble Space Telescope data. The inferred viewing angles of the LMC disc (i = 33.5 degrees(+1.2)(-1.3), Theta = 129.8 degrees(+1.9)(-1.9)) are in good agreement with values from the literature but suggest a higher inclination of the central parts of the LMC. Our data confirm a higher rotation amplitude for the young (less than or similar to 0.5 Gyr) stars compared to the intermediate-age/old (greater than or similar to 1 Gyr) population, which can be explained by asymmetric drift. We constructed spatially resolved velocity maps of the intermediate-age/old and young populations. Intermediate-age/old stars follow elongated orbits parallel to the bar's major axis, providing first observational evidence for x(1) orbits within the LMC bar. In the innermost regions, the motions show more chaotic structures. Young stars show motions along a central filamentary bar structure.}, language = {en} } @article{AlvaradoGomezCohenDrakeetal.2022, author = {Alvarado-G{\´o}mez, Juli{\´a}n D. and Cohen, Ofer and Drake, Jeremy J. and Fraschetti, Federico and Poppenh{\"a}ger, Katja and Garraffo, Cecilia and Chebly, Judy and Ilin, Ekaterina and Harbach, Laura and Kochukhov, Oleg}, title = {Simulating the space weather in the AU Mic system: stellar winds and extreme coronal mass ejections}, series = {Astrophysical journal}, volume = {928}, journal = {Astrophysical journal}, number = {2}, publisher = {IOP Publishing}, address = {Bristol}, issn = {1538-4357}, doi = {10.3847/1538-4357/ac54b8}, pages = {12}, year = {2022}, abstract = {Two close-in planets have been recently found around the M-dwarf flare star AU Microscopii (AU Mic). These Neptune-sized planets (AU Mic b and c) seem to be located very close to the so-called "evaporation valley" in the exoplanet population, making this system an important target for studying atmospheric loss on exoplanets. This process, while mainly driven by high-energy stellar radiation, will be strongly mediated by the space environment surrounding the planets. Here we present an investigation of this last area, performing 3D numerical modeling of the quiescent stellar wind from AU Mic, as well as time-dependent simulations describing the evolution of a highly energetic coronal mass ejection (CME) event in this system. Observational constraints on the stellar magnetic field and properties of the eruption are incorporated in our models. We carry out qualitative and quantitative characterizations of the stellar wind, the emerging CMEs, as well as the expected steady and transient conditions along the orbit of both exoplanets. Our results predict extreme space weather for AU Mic and its planets. This includes sub-Alfvenic regions for the large majority of the exoplanet orbits, very high dynamic and magnetic pressure values in quiescence (varying within 10(2)-10(5) times the dynamic pressure experienced by Earth), and an even harsher environment during the passage of any escaping CME associated with the frequent flaring observed in AU Mic. These space weather conditions alone pose an immense challenge for the survival of exoplanetary atmospheres (if any) in this system.}, language = {en} } @article{GeistGallagherKotullaetal.2022, author = {Geist, Emily and Gallagher, John S. and Kotulla, Ralf and Oskinova, Lida and Hamann, Wolf-Rainer and Ramachandran, Varsha and Sabbi, Elena and Smith, Linda J. and Kniazev, Alexey and Nota, Antonella and Rickard, Matthew J.}, title = {Ionization and star formation in the giant H ii region SMC-N66}, series = {Publications of the Astronomical Society of the Pacific}, volume = {134}, journal = {Publications of the Astronomical Society of the Pacific}, number = {1036}, publisher = {IOP Publishing}, address = {Bristol}, issn = {0004-6280}, doi = {10.1088/1538-3873/ac697b}, pages = {11}, year = {2022}, abstract = {The NGC 346 young stellar system and associated N66 giant H ii region in the Small Magellanic Cloud are the nearest example of a massive star-forming event in a low metallicity (Z approximate to 0.2Z (circle dot)) galaxy. With an age of less than or similar to 3 Myr this system provides a unique opportunity to study relationships between massive stars and their associated H ii region. Using archival data, we derive a total H alpha luminosity of L(H alpha) = 4.1 x 10(38) erg s(-1) corresponding to an H-photoionization rate of 3 x 10(50) s(-1). A comparison with a predicted stellar ionization rate derived from the more than 50 known O-stars in NGC 346, including massive stars recently classified from Hubble Space Telescope far-ultraviolet (FUV) spectra, indicates an approximate ionization balance. Spectra obtained with SALT suggest the ionization structure of N66 could be consistent with some leakage of ionizing photons. Due to the low metallicity, the FUV luminosity from NGC 346 is not confined to the interstellar cloud associated with N66. Ionization extends through much of the spatial extent of the N66 cloud complex, and most of the cloud mass is not ionized. The stellar mass estimated from nebular L(H alpha) appears to be lower than masses derived from the census of resolved stars which may indicate a disconnect between the formation of high and low mass stars in this region. We briefly discuss implications of the properties of N66 for studies of star formation and stellar feedback in low metallicity environments.}, language = {en} } @article{PerottoniLimbergAmaranteetal.2022, author = {Perottoni, H{\´e}lio D. and Limberg, Guilherme and Amarante, Jo{\~a}o A. S. and Rossi, Silvia and Queiroz, Anna B. A. and Santucci, Rafael M. and P{\´e}rez-Villegas, Angeles and Chiappini, Cristina}, title = {The unmixed debris of Gaia-Sausage/Enceladus in the form of a pair of halo stellar overdensities}, series = {Astrophysical journal letters}, volume = {936}, journal = {Astrophysical journal letters}, number = {1}, publisher = {IOP Publishing}, address = {Bristol}, issn = {2041-8213}, doi = {10.3847/2041-8213/ac88d6}, pages = {7}, year = {2022}, abstract = {In the first billion years after its formation, the galaxy underwent several mergers with dwarf satellites of various masses. The debris of Gaia-Sausage/Enceladus (GSE), the galaxy responsible for the last significant merger of the Milky Way, dominates the inner halo and has been suggested to be the progenitor of both the Hercules-Aquila Cloud (HAC) and Virgo Overdensity (VOD). We combine SEGUE, APOGEE, Gaia, and StarHorse distances to characterize the chemodynamical properties and verify the link between HAC, VOD, and GSE. We find that the orbital eccentricity distributions of the stellar overdensities and GSE are comparable. We also find that they have similar, strongly peaked, metallicity distribution functions, reinforcing the hypothesis of common origin. Furthermore, we show that HAC and VOD are indistinguishable from the prototypical GSE population within all chemical-abundance spaces analyzed. All these evidences combined provide a clear demonstration that the GSE merger is the main progenitor of the stellar populations found within these halo overdensities.}, language = {en} } @article{StojkoskiJolakoskiPaletal.2022, author = {Stojkoski, Viktor and Jolakoski, Petar and Pal, Arnab and Sandev, Trifce and Kocarev, Ljupco and Metzler, Ralf}, title = {Income inequality and mobility in geometric Brownian motion with stochastic resetting: theoretical results and empirical evidence of non-ergodicity}, series = {Philosophical transactions of the Royal Society A: Mathematical, physical and engineering sciences}, volume = {380}, journal = {Philosophical transactions of the Royal Society A: Mathematical, physical and engineering sciences}, number = {2224}, publisher = {Royal Society}, address = {London}, issn = {1364-503X}, doi = {10.1098/rsta.2021.0157}, pages = {17}, year = {2022}, abstract = {We explore the role of non-ergodicity in the relationship between income inequality, the extent of concentration in the income distribution, and income mobility, the feasibility of an individual to change their position in the income rankings. For this purpose, we use the properties of an established model for income growth that includes 'resetting' as a stabilizing force to ensure stationary dynamics. We find that the dynamics of inequality is regime-dependent: it may range from a strictly non-ergodic state where this phenomenon has an increasing trend, up to a stable regime where inequality is steady and the system efficiently mimics ergodicity. Mobility measures, conversely, are always stable over time, but suggest that economies become less mobile in non-ergodic regimes. By fitting the model to empirical data for the income share of the top earners in the USA, we provide evidence that the income dynamics in this country is consistently in a regime in which non-ergodicity characterizes inequality and immobility. Our results can serve as a simple rationale for the observed real-world income dynamics and as such aid in addressing non-ergodicity in various empirical settings across the globe.This article is part of the theme issue 'Kinetic exchange models of societies and economies'.}, language = {en} } @article{LiuIgnatovaKimbergetal.2022, author = {Liu, Ji-Cai and Ignatova, Nina and Kimberg, Victor and Krasnov, Pavel and F{\"o}hlisch, Alexander and Simon, Marc and Gel'mukhanov, Faris}, title = {Time-resolved study of recoil-induced rotation by X-ray pump - X-ray probe spectroscopy}, series = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, volume = {24}, journal = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, number = {11}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1463-9076}, doi = {10.1039/d1cp05000a}, pages = {6627 -- 6638}, year = {2022}, abstract = {Modern stationary X-ray spectroscopy is unable to resolve rotational structure. In the present paper, we propose to use time-resolved two color X-ray pump-probe spectroscopy with picosecond resolution for real-time monitoring of the rotational dynamics induced by the recoil effect. The proposed technique consists of two steps. The first short pump X-ray pulse ionizes the valence electron, which transfers angular momentum to the molecule. The second time-delayed short probe X-ray pulse resonantly excites a 1s electron to the created valence hole. Due to the recoil-induced angular momentum the molecule rotates and changes the orientation of transition dipole moment of core-excitation with respect to the transition dipole moment of the valence ionization, which results in a temporal modulation of the probe X-ray absorption as a function of the delay time between the pulses. We developed an accurate theory of the X-ray pump-probe spectroscopy of the recoil-induced rotation and study how the energy of the photoelectron and thermal dephasing affect the structure of the time-dependent X-ray absorption using the CO molecule as a case-study. We also discuss the feasibility of experimental observation of our theoretical findings, opening new perspectives in studies of molecular rotational dynamics.}, language = {en} } @article{AbiusoHolubecAndersetal.2022, author = {Abiuso, Paolo and Holubec, Viktor and Anders, Janet and Ye, Zhuolin and Cerisola, Federico and Perarnau-Llobet, Marti}, title = {Thermodynamics and optimal protocols of multidimensional quadratic Brownian systems}, series = {Journal of physics communications}, volume = {6}, journal = {Journal of physics communications}, number = {6}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {2399-6528}, doi = {10.1088/2399-6528/ac72f8}, pages = {15}, year = {2022}, abstract = {We characterize finite-time thermodynamic processes of multidimensional quadratic overdamped systems. Analytic expressions are provided for heat, work, and dissipation for any evolution of the system covariance matrix. The Bures-Wasserstein metric between covariance matrices naturally emerges as the local quantifier of dissipation. General principles of how to apply these geometric tools to identify optimal protocols are discussed. Focusing on the relevant slow-driving limit, we show how these results can be used to analyze cases in which the experimental control over the system is partial.}, language = {en} } @article{VoroshninTarasovBokaietal.2022, author = {Voroshnin, Vladimir and Tarasov, Artem V. and Bokai, Kirill A. and Chikina, Alla and Senkovskiy, Boris V. and Ehlen, Niels and Usachov, Dmitry Yu. and Gruneis, Alexander and Krivenkov, Maxim and Sanchez-Barriga, Jaime and Fedorov, Alexander}, title = {Direct spectroscopic evidence of magnetic proximity effect in MoS2 monolayer on graphene/Co}, series = {ACS nano}, volume = {16}, journal = {ACS nano}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {1936-0851}, doi = {10.1021/acsnano.1c10391}, pages = {7448 -- 7456}, year = {2022}, abstract = {A magnetic field modifies optical properties and provides valley splitting in a molybdenum disulfide (MoS2) monolayer. Here we demonstrate a scalable approach to the epitaxial synthesis of MoS2 monolayer on a magnetic graphene/Co system. Using spin- and angle-resolved photoemission spectroscopy we observe a magnetic proximity effect that causes a 20 meV spin-splitting at the (Gamma) over bar point and canting of spins at the (K) over bar point in the valence band toward the in-plane direction of cobalt magnetization. Our density functional theory calculations reveal that the in-plane spin component at (K) over bar is localized on Co atoms in the valence band, while in the conduction band it is localized on the MoS2 layer. The calculations also predict a 16 meV spin-splitting at the (Gamma) over bar point and 8 meV (K) over bar-(K) over bar' valley asymmetry for an out-of-plane magnetization. These findings suggest control over optical transitions in MoS2 via Co magnetization. Our estimations show that the magnetic proximity effect is equivalent to the action of the magnetic field as large as 100 T.}, language = {en} } @article{MillerCionideGrijsetal.2022, author = {Miller, Amy E. and Cioni, Maria-Rosa L. and de Grijs, Richard and Sun, Ning-Chen and Bell, Cameron P. M. and Choudhury, Samyaday and Ivanov, Valentin D. and Marconi, Marcella and Oliveira, Joana M. and Petr-Gotzens, Monika and Ripepi, Vincenzo and van Loon, Jacco Th.}, title = {The VMC survey - XLVII. Turbulence-controlled hierarchical star formation in the large magellanic cloud}, series = {Monthly notices of the Royal Astronomical Society}, volume = {512}, journal = {Monthly notices of the Royal Astronomical Society}, number = {1}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stac508}, pages = {1196 -- 1213}, year = {2022}, abstract = {We perform a statistical clustering analysis of upper main-sequence stars in the Large Magellanic Cloud (LMC) using data from the Visible and Infrared Survey Telescope for Astronomy survey of the Magellanic Clouds. We map over 2500 young stellar structures at 15 significance levels across similar to 120 square degrees centred on the LMC. The structures have sizes ranging from a few parsecs to over 1 kpc. We find that the young structures follow power-law size and mass distributions. From the perimeter-area relation, we derive a perimeter-area dimension of 1.44 +/- 0.20. From the mass-size relation and the size distribution, we derive two-dimensional fractal dimensions of 1.50 +/- 0.10 and 1.61 +/- 0.20, respectively. We find that the surface density distribution is well represented by a lognormal distribution. We apply the Larson relation to estimate the velocity dispersions and crossing times of these structures. Our results indicate that the fractal nature of the young stellar structures has been inherited from the gas clouds from which they form and that this architecture is generated by supersonic turbulence. Our results also suggest that star formation in the LMC is scale-free from 10 to 700 pc.}, language = {en} } @article{GriggioBedinRaddietal.2022, author = {Griggio, Massimo and Bedin, Luigi R. and Raddi, Roberto and Reindl, Nicole and Tomasella, Lina and Scalco, M. and Salaris, M. and Cassisi, S. and Ochner, P. and Ciroi, S. and Rosati, P. and Nardiello, Domenico and Anderson, J. and Libralato, Mattia and Bellini, A. and Vallenari, A. and Spina, L. and Pedani, M.}, title = {Astro-photometric study of M37 with Gaia and wide-field ugi-imaging}, series = {Monthly notices of the Royal Astronomical Society}, volume = {515}, journal = {Monthly notices of the Royal Astronomical Society}, number = {2}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stac1920}, pages = {1841 -- 1853}, year = {2022}, abstract = {We present an astrometric and photometric wide-field study of the Galactic open star cluster M37 (NGC 2099). The studied field was observed with ground-based images covering a region of about four square degrees in the Sloan-like filters ugi. We exploited the Gaia catalogue to calibrate the geometric distortion of the large field mosaics, developing software routines that can be also applied to other wide-field instruments. The data are used to identify the hottest white dwarf (WD) member candidates of M37. Thanks to the Gaia EDR3 exquisite astrometry we identified seven such WD candidates, one of which, besides being a high-probability astrometric member, is the putative central star of a planetary nebula. To our knowledge, this is a unique object in an open cluster, and we have obtained follow-up low-resolution spectra that are used for a qualitative characterization of this young WD. Finally, we publicly release a three-colour atlas and a catalogue of the sources in the field of view, which represents a complement of existing material.}, language = {en} } @article{PelisoliDorschHeberetal.2022, author = {Pelisoli, Ingrid and Dorsch, Matti and Heber, Ulrich and G{\"a}nsicke, Boris and Geier, Stephan and Kupfer, Thomas and Nemeth, Peter and Scaringi, Simone and Schaffenroth, Veronika}, title = {Discovery and analysis of three magnetic hot subdwarf stars}, series = {Monthly notices of the Royal Astronomical Society}, volume = {515}, journal = {Monthly notices of the Royal Astronomical Society}, number = {2}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stac1069}, pages = {2496 -- 2510}, year = {2022}, abstract = {Magnetic fields can play an important role in stellar evolution. Among white dwarfs, the most common stellar remnant, the fraction of magnetic systems is more than 20 per cent. The origin of magnetic fields in white dwarfs, which show strengths ranging from 40 kG to hundreds of MG, is still a topic of debate. In contrast, only one magnetic hot subdwarf star has been identified out of thousands of known systems. Hot subdwarfs are formed from binary interaction, a process often associated with the generation of magnetic fields, and will evolve to become white dwarfs, which makes the lack of detected magnetic hot subdwarfs a puzzling phenomenon. Here we report the discovery of three new magnetic hot subdwarfs with field strengths in the range 300-500 kG. Like the only previously known system, they are all helium-rich O-type stars (He-sdOs). We analysed multiple archival spectra of the three systems and derived their stellar properties. We find that they all lack radial velocity variability, suggesting formation via a merger channel. However, we derive higher than typical hydrogen abundances for their spectral type, which are in disagreement with current model predictions. Our findings suggest a lower limit to the magnetic fraction of hot subdwarfs of 0.147(+0.143)(-0.047) per cent, and provide evidence for merger-induced magnetic fields which could explain white dwarfs with field strengths of 50-150 MG, assuming magnetic flux conservation.}, language = {en} } @article{BornJohanssonLeitneretal.2022, author = {Born, Artur and Johansson, Fredrik O. L. and Leitner, Torsten and Bidermane, Ieva and Kuehn, Danilo and Martensson, Nils and F{\"o}hlisch, Alexander}, title = {The degree of electron itinerancy and shell closing in the core-ionized state of transition metals probed by Auger-photoelectron coincidence spectroscopy}, series = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, volume = {24}, journal = {Physical chemistry, chemical physics : a journal of European Chemical Societies}, number = {32}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1463-9076}, doi = {10.1039/d2cp02477b}, pages = {19218 -- 19222}, year = {2022}, abstract = {Auger-photoelectron coincidence spectroscopy (APECS) has been used to examine the electron correlation and itinerance effects in transition metals Cu, Ni and Co. It is shown that the LVV Auger, in coincidence with 2p photoelectrons, spectra can be represented using atomic multiplet positions if the 3d-shell is localized (atomic-like) and with a self-convoluted valence band for band-like (itinerant) materials as explained using the Cini-Sawatzky model. For transition metals, the 3d band changes from band-like to localized with increasing atomic number, with the possibility of a mixed behavior. Our result shows that the LVV spectra of Cu can be represented by atomic multiplet calculations, those of Co resemble the self-convolution of the valence band and those of Ni are a mixture of both, consistent with the Cini-Sawatzky model.}, language = {en} } @article{NeunteufelPreeceKruckowetal.2022, author = {Neunteufel, Patrick and Preece, H. and Kruckow, Matthias U. and Geier, Stephan and Hamers, Adrian S. and Justham, S. and Podsiadlowski, Philipp}, title = {Properties and applications of a predicted population of runaway He-sdO/B stars ejected from single degenerate He-donor SNe}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {663}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0004-6361}, doi = {10.1051/0004-6361/202142864}, pages = {26}, year = {2022}, abstract = {Context. Thermonuclear supernovae (SNe), a subset of which are the highly important SNe of Type Ia and Iax, are relatively poorly understood phenomena. One of the more promising scenarios leading up to the creation of a thermonuclear SN involves accretion of helium-rich material from a binary companion. Following the SN, the binary companion is then ejected from the location of the progenitor binary at velocities possibly large enough to unbind it from the gravitational potential of the Galaxy. Ejected companion stars should form a detectable population, if their production mechanism is not exceedingly rare. Aims. This study builds on previous works, producing the most extensive prediction of the properties of such a hypothetical population to date, taking both Chandrasekhar and non-Chandrasekhar mass events into account. These results are then used to define criteria for membership of this population and characterise putative subpopulations. Methods. This study contains 6 x 10(6) individual ejection trajectories out of the Galactic plane calculated with the stellar kinematics framework SHyRT, which are analysed with regard to their bulk observational properties. These are then put into context with the only previously identified population member US 708 and applied to a number of other possible candidate objects. Results. We find that two additional previously observed objects possess properties to warrant a designation as candidate objects. Characterisation of these object with respect to the predicted population finds all of them to be extreme in at least one astrometric observable. Higher mass ( >0 :7 M-circle dot) objects should be over-represented in the observationally accessible volume, with the ratio of bound to unbound objects being an accessible observable for the determination of the dominant terminal accretor mass. We find that current observations of runaway candidates within 10 kpc support a Galactic SN rate of the order of similar to 3 x 10(-7) yr(-1) to similar to 2 x 10(-6) yr(-1), three orders of magnitude below the inferred Galactic SN Ia rate and two orders of magnitude below the formation rate of predicted He-donor progenitors. Conclusions. The number of currently observed population members suggests that the He-donor scenario, as suspected before, is not a dominant contributor to the number of observed SNe Ia. However, even at the low event rate suggested, we find that the majority of possibly detectable population members is still undetected. The extreme nature of current population members suggests that a still larger number of objects has simply evaded detection up to this point, hinting at a higher contribution than is currently supported by observation.}, language = {en} } @article{StojkoskiSandevKocarevetal.2022, author = {Stojkoski, Viktor and Sandev, Trifce and Kocarev, Ljupco and Pal, Arnab}, title = {Autocorrelation functions and ergodicity in diffusion with stochastic resetting}, series = {Journal of physics : A, Mathematical and theoretical}, volume = {55}, journal = {Journal of physics : A, Mathematical and theoretical}, number = {10}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {1751-8113}, doi = {10.1088/1751-8121/ac4ce9}, pages = {22}, year = {2022}, abstract = {Diffusion with stochastic resetting is a paradigm of resetting processes. Standard renewal or master equation approach are typically used to study steady state and other transport properties such as average, mean squared displacement etc. What remains less explored is the two time point correlation functions whose evaluation is often daunting since it requires the implementation of the exact time dependent probability density functions of the resetting processes which are unknown for most of the problems. We adopt a different approach that allows us to write a stochastic solution for a single trajectory undergoing resetting. Moments and the autocorrelation functions between any two times along the trajectory can then be computed directly using the laws of total expectation. Estimation of autocorrelation functions turns out to be pivotal for investigating the ergodic properties of various observables for this canonical model. In particular, we investigate two observables (i) sample mean which is widely used in economics and (ii) time-averaged-mean-squared-displacement (TAMSD) which is of acute interest in physics. We find that both diffusion and drift-diffusion processes with resetting are ergodic at the mean level unlike their reset-free counterparts. In contrast, resetting renders ergodicity breaking in the TAMSD while both the stochastic processes are ergodic when resetting is absent. We quantify these behaviors with detailed analytical study and corroborate with extensive numerical simulations. Our results can be verified in experimental set-ups that can track single particle trajectories and thus have strong implications in understanding the physics of resetting.}, language = {en} } @article{LongNiCaoetal.2022, author = {Long, Minyi and Ni, Binbin and Cao, Xing and Gu, Xudong and Kollmann, Peter and Luo, Qiong and Zhou, Ruoxian and Guo, Yingjie and Guo, Deyu and Shprits, Yuri}, title = {Losses of radiation belt energetic particles by encounters with four of the inner Moons of Jupiter}, series = {Journal of geophysical research, Planets}, volume = {127}, journal = {Journal of geophysical research, Planets}, number = {2}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9097}, doi = {10.1029/2021JE007050}, pages = {13}, year = {2022}, abstract = {Based on an improved model of the moon absorption of Jovian radiation belt particles, we investigate quantitatively and comprehensively the absorption probabilities and particle lifetimes due to encounters with four of the inner moons of Jupiter (Amalthea, Thebe, Io, and Europa) inside L < 10. Our results demonstrate that the resultant average lifetimes of energetic protons and electrons vary dramatically between similar to 0.1 days and well above 1,000 days, showing a strong dependence on the particle equatorial pitch angle, kinetic energy and moon orbit. The average lifetimes of energetic protons and electrons against moon absorption are shortest for Io (i.e., similar to 0.1-10 days) and longest for Thebe (i.e., up to thousands of days), with the lifetimes in between for Europa and Amalthea. Due to the diploe tilt angle absorption effect, the average lifetimes of energetic protons and electrons vary markedly below and above alpha eq \${\alpha }_{\mathrm{e}\mathrm{q}}\$ = 67 degrees. Overall, the average electron lifetimes exhibit weak pitch angle dependence, but the average proton lifetimes are strongly dependent on equatorial pitch angle. The average lifetimes of energetic protons decrease monotonically and substantially with the kinetic energy, but the average lifetimes of energetic electrons are roughly constant at energies 100 GeV) gamma-ray emission observed from a number of supernova remnants (SNRs) indicates particle acceleration to high energies at the shock of the remnants and a potentially significant contribution to Galactic cosmic rays. It is extremely difficult to determine whether protons (through hadronic interactions and subsequent pion decay) or electrons (through inverse Compton scattering on ambient photon fields) are responsible for this emission. For a successful diagnostic, a good understanding of the spatial and energy distribution of the underlying particle population is crucial. Most SNRs are created in core-collapse explosions and expand into the wind bubble of their progenitor stars. This circumstellar medium features a complex spatial distribution of gas and magnetic field which naturally strongly affects the resulting particle population. In this work, we conduct a detailed study of the spectro-spatial evolution of the electrons accelerated at the forward shock of core-collapse SNRs and their nonthermal radiation, using the RATPaC code that is designed for the time- and spatially dependent treatment of particle acceleration at SNR shocks. We focus on the impact of the spatially inhomogeneous magnetic field through the efficiency of diffusion and synchrotron cooling. It is demonstrated that the structure of the circumstellar magnetic field can leave strong signatures in the spectrum and morphology of the resulting nonthermal emission.}, language = {en} } @article{HerzogReppertPudelletal.2022, author = {Herzog, Marc and Reppert, Alexander von and Pudell, Jan-Etienne and Henkel, Carsten and Kronseder, Matthias and Back, Christian H. and Maznev, Alexei A. and Bargheer, Matias}, title = {Phonon-dominated energy transport in purely metallic heterostructures}, series = {Advanced functional materials}, volume = {32}, journal = {Advanced functional materials}, number = {41}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1616-301X}, doi = {10.1002/adfm.202206179}, pages = {8}, year = {2022}, abstract = {Ultrafast X-ray diffraction is used to quantify the transport of energy in laser-excited nanoscale gold-nickel (Au-Ni) bilayers. Electron transport and efficient electron-phonon coupling in Ni convert the laser-deposited energy in the conduction electrons within a few picoseconds into a strong non-equilibrium between hot Ni and cold Au phonons at the bilayer interface. Modeling of the subsequent equilibration dynamics within various two-temperature models confirms that for ultrathin Au films, the thermal transport is dominated by phonons instead of conduction electrons because of the weak electron-phonon coupling in Au.}, language = {en} } @article{YanXueJiangetal.2022, author = {Yan, Xiaoli and Xue, Zhike and Jiang, Chaowei and Priest, E. R. and Kliem, Bernhard and Yang, Liheng and Wang, Jincheng and Kong, Defang and Song, Yongliang and Feng, Xueshang and Liu, Zhong}, title = {Fast plasmoid-mediated reconnection in a solar flare}, series = {Nature Communications}, volume = {13}, journal = {Nature Communications}, number = {1}, publisher = {Nature Publishing Group UK}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-022-28269-w}, pages = {14}, year = {2022}, abstract = {Magnetic reconnection is a multi-faceted process of energy conversion in astrophysical, space and laboratory plasmas that operates at microscopic scales but has macroscopic drivers and consequences. Solar flares present a key laboratory for its study, leaving imprints of the microscopic physics in radiation spectra and allowing the macroscopic evolution to be imaged, yet a full observational characterization remains elusive. Here we combine high resolution imaging and spectral observations of a confined solar flare at multiple wavelengths with data-constrained magnetohydrodynamic modeling to study the dynamics of the flare plasma from the current sheet to the plasmoid scale. The analysis suggests that the flare resulted from the interaction of a twisted magnetic flux rope surrounding a filament with nearby magnetic loops whose feet are anchored in chromospheric fibrils. Bright cusp-shaped structures represent the region around a reconnecting separator or quasi-separator (hyperbolic flux tube). The fast reconnection, which is relevant for other astrophysical environments, revealed plasmoids in the current sheet and separatrices and associated unresolved turbulent motions. Solar flares provide wide range of observational details about fundamental processes involved. Here, the authors show evidence for magnetic reconnection in a strong confined solar flare displaying all four reconnection flows with plasmoids in the current sheet and the separatrices.}, language = {en} } @article{ProlSmirnovHoqueetal.2022, author = {Prol, Fabricio S. and Smirnov, Artem G. and Hoque, M. Mainul and Shprits, Yuri}, title = {Combined model of topside ionosphere and plasmasphere derived from radio-occultation and Van Allen Probes data}, series = {Scientific reports}, volume = {12}, journal = {Scientific reports}, number = {1}, publisher = {Macmillan Publishers Limited, part of Springer Nature}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-022-13302-1}, pages = {11}, year = {2022}, abstract = {In the last years, electron density profile functions characterized by a linear dependence on the scale height showed good results when approximating the topside ionosphere. The performance above 800 km, however, is not yet well investigated. This study investigates the capability of the semi-Epstein functions to represent electron density profiles from the peak height up to 20,000 km. Electron density observations recorded by the Van Allen Probes were used to resolve the scale height dependence in the plasmasphere. It was found that the linear dependence of the scale height in the topside ionosphere cannot be directly used to extrapolate profiles above 800 km. We find that the dependence of scale heights on altitude is quadratic in the plasmasphere. A statistical model of the scale heights is therefore proposed. After combining the topside ionosphere and plasmasphere by a unified model, we have obtained good estimations not only in the profile shapes, but also in the Total Electron Content magnitude and distributions when compared to actual measurements from 2013, 2014, 2016 and 2017. Our investigation shows that Van Allen Probes can be merged to radio-occultation data to properly represent the upper ionosphere and plasmasphere by means of a semi-Epstein function.}, language = {en} }