TY  - JOUR
A1  - Henkel, Carsten
A1  - Jacob, Georg
A1  - Stopp, Felix
A1  - Schmidt-Kaler, Ferdinand
A1  - Keil, Mark
A1  - Japha, Yonathan
A1  - Folman, Ron
T1  - Stern-Gerlach splitting of low-energy ion beams
JF  - New journal of physics : the open-access journal for physics
N2  - We present a feasibility study with several magnetic field configurations for creating spin-dependent forces that can split a low-energy ion beam by the Stern-Gerlach (SG) effect. To the best of our knowledge, coherent spin-splittings of charged particles have yet to be realised. Our proposal is based on ion source parameters taken from a recent experiment that demonstrated single-ion implantation from a high-brightness ion source combined with a radio-frequency Paul trap. The inhomogeneous magnetic fields can be created by permanently magnetised microstructures or from current-carrying wires with sizes in the micron range, such as those recently used in a successful implementation of the SG effect with neutral atoms. All relevant forces (Lorentz force and image charges) are taken into account, and measurable splittings are found by analytical and numerical calculations.
KW  - spin-dependent forces
KW  - Stern-Gerlach effect
KW  - ion optics
KW  - beam splitter
KW  - magnetic microstructures
Y1  - 2019
U6  - https://doi.org/10.1088/1367-2630/ab36c7
SN  - 1367-2630
VL  - 21
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Kurths, Jürgen
A1  - Agarwal, Ankit
A1  - Shukla, Roopam
A1  - Marwan, Norbert
A1  - Maheswaran, Rathinasamy
A1  - Caesar, Levke
A1  - Krishnan, Raghavan
A1  - Merz, Bruno
T1  - Unravelling the spatial diversity of Indian precipitation teleconnections via a non-linear multi-scale approach
JF  - Nonlinear processes in geophysics
N2  - A better understanding of precipitation dynamics in the Indian subcontinent is required since India's society depends heavily on reliable monsoon forecasts. We introduce a non-linear, multiscale approach, based on wavelets and event synchronization, for unravelling teleconnection influences on precipitation. We consider those climate patterns with the highest relevance for Indian precipitation. Our results suggest significant influences which are not well captured by only the wavelet coherence analysis, the state-of-the-art method in understanding linkages at multiple timescales. We find substantial variation across India and across timescales. In particular, El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) mainly influence precipitation in the south-east at interannual and decadal scales, respectively, whereas the North Atlantic Oscillation (NAO) has a strong connection to precipitation, particularly in the northern regions. The effect of the Pacific Decadal Oscillation (PDO) stretches across the whole country, whereas the Atlantic Multidecadal Oscillation (AMO) influences precipitation particularly in the central arid and semi-arid regions. The proposed method provides a powerful approach for capturing the dynamics of precipitation and, hence, helps improve precipitation forecasting.
Y1  - 2019
U6  - https://doi.org/10.5194/npg-26-251-2019
SN  - 1023-5809
SN  - 1607-7946
VL  - 26
IS  - 3
SP  - 251
EP  - 266
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Wolf, Thomas J. A.
A1  - Parrish, Robert M.
A1  - Myhre, Rolf H.
A1  - Martinez, Todd J.
A1  - Koch, Henrik
A1  - Gühr, Markus
T1  - Observation of Ultrafast Intersystem Crossing in Thymine by Extreme Ultraviolet Time-Resolved Photoelectron Spectroscopy
JF  - The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment & general theory
N2  - We studied the photoinduced ultrafast relaxation dynamics of the nucleobase thymine using gas-phase time-resolved photoelectron spectroscopy. By employing extreme ultraviolet pulses from high harmonic generation for photoionization, we substantially extend our spectral observation window with respect to previous studies. This enables us to follow relaxation of the excited state population all the way to low-lying electronic states including the ground state. In thymine, we observe relaxation from the optically bright (1)pi pi* state of thymine to a dark (1)n pi* state within 80 +/- 30 fs. The (1)n pi* state relaxes further within 3.5 +/- 0.3 ps to a low-lying electronic state. By comparison with quantum chemical simulations, we can unambiguously assign its spectroscopic signature to the (3)pi pi* state. Hence, our study draws a comprehensive picture of the relaxation mechanism of thymine including ultrafast intersystem crossing to the triplet manifold.
Y1  - 2019
U6  - https://doi.org/10.1021/acs.jpca.9b05573
SN  - 1089-5639
SN  - 1520-5215
VL  - 123
IS  - 32
SP  - 6897
EP  - 6903
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Nikolis, Vasileios C.
A1  - Mischok, Andreas
A1  - Siegmund, Bernhard
A1  - Kublitski, Jonas
A1  - Jia, Xiangkun
A1  - Benduhn, Johannes
A1  - Hörmann, Ulrich
A1  - Neher, Dieter
A1  - Gather, Malte C.
A1  - Spoltore, Donato
A1  - Vandewal, Koen
T1  - Strong light-matter coupling for reduced photon energy losses in organic photovoltaics
JF  - Nature Communications
N2  - Strong light-matter coupling can re-arrange the exciton energies in organic semiconductors. Here, we exploit strong coupling by embedding a fullerene-free organic solar cell (OSC) photo-active layer into an optical microcavity, leading to the formation of polariton peaks and a red-shift of the optical gap. At the same time, the open-circuit voltage of the device remains unaffected. This leads to reduced photon energy losses for the low-energy polaritons and a steepening of the absorption edge. While strong coupling reduces the optical gap, the energy of the charge-transfer state is not affected for large driving force donor-acceptor systems. Interestingly, this implies that strong coupling can be exploited in OSCs to reduce the driving force for electron transfer, without chemical or microstructural modifications of the photoactive layer. Our work demonstrates that the processes determining voltage losses in OSCs can now be tuned, and reduced to unprecedented values, simply by manipulating the device architecture.
Y1  - 2019
U6  - https://doi.org/10.1038/s41467-019-11717-5
SN  - 2041-1723
VL  - 10
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Stolterfoht, Martin
A1  - Caprioglio, Pietro
A1  - Wolff, Christian Michael
A1  - Marquez, Jose A.
A1  - Nordmann, Joleik
A1  - Zhang, Shanshan
A1  - Rothhardt, Daniel
A1  - Hörmann, Ulrich
A1  - Amir, Yohai
A1  - Redinger, Alex
A1  - Kegelmann, Lukas
A1  - Zu, Fengshuo
A1  - Albrecht, Steve
A1  - Koch, Norbert
A1  - Kirchartz, Thomas
A1  - Saliba, Michael
A1  - Unold, Thomas
A1  - Neher, Dieter
T1  - The impact of energy alignment and interfacial recombination on the internal and external open-circuit voltage of perovskite solar cells
JF  - Energy & environmental science
N2  - Charge transport layers (CTLs) are key components of diffusion controlled perovskite solar cells, however, they can induce additional non-radiative recombination pathways which limit the open circuit voltage (V-OC) of the cell. In order to realize the full thermodynamic potential of the perovskite absorber, both the electron and hole transport layer (ETL/HTL) need to be as selective as possible. By measuring the photoluminescence yield of perovskite/CTL heterojunctions, we quantify the non-radiative interfacial recombination currents in pin- and nip-type cells including high efficiency devices (21.4%). Our study comprises a wide range of commonly used CTLs, including various hole-transporting polymers, spiro-OMeTAD, metal oxides and fullerenes. We find that all studied CTLs limit the V-OC by inducing an additional non-radiative recombination current that is in most cases substantially larger than the loss in the neat perovskite and that the least-selective interface sets the upper limit for the V-OC of the device. Importantly, the V-OC equals the internal quasi-Fermi level splitting (QFLS) in the absorber layer only in high efficiency cells, while in poor performing devices, the V-OC is substantially lower than the QFLS. Using ultraviolet photoelectron spectroscopy and differential charging capacitance experiments we show that this is due to an energy level mis-alignment at the p-interface. The findings are corroborated by rigorous device simulations which outline important considerations to maximize the V-OC. This work highlights that the challenge to suppress non-radiative recombination losses in perovskite cells on their way to the radiative limit lies in proper energy level alignment and in suppression of defect recombination at the interfaces.
Y1  - 2019
U6  - https://doi.org/10.1039/c9ee02020a
SN  - 1754-5692
SN  - 1754-5706
VL  - 12
IS  - 9
SP  - 2778
EP  - 2788
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Le Corre, Vincent M.
A1  - Stolterfoht, Martin
A1  - Perdigón-Toro, Lorena
A1  - Feuerstein, Markus
A1  - Wolff, Christian Michael
A1  - Gil-Escrig, Lidon
A1  - Bolink, Henk J.
A1  - Neher, Dieter
A1  - Koster, L. Jan Anton
T1  - Charge Transport Layers Limiting the Efficiency of Perovskite Solar Cells: How To Optimize Conductivity, Doping, and Thickness
JF  - ACS Applied Energy Materials
N2  - Perovskite solar cells (PSCs) are one of the main research topics of the photovoltaic community; with efficiencies now reaching up to 24%, PSCs are on the way to catching up with classical inorganic solar cells. However, PSCs have not yet reached their full potential. In fact, their efficiency is still limited by nonradiative recombination, mainly via trap-states and by losses due to the poor transport properties of the commonly used transport layers (TLs). Indeed, state-of-the-art TLs (especially if organic) suffer from rather low mobilities, typically within 10(-5) and 10(-2) cm(-2) V-1 s(-1), when compared to the high mobilities, 1-10 cm(-2) V-1 s(-1), measured for perovskites. This work presents a comprehensive analysis of the effect of the mobility, thickness, and doping density of the transport layers based on combined experimental and modeling results of two sets of devices made of a solution-processed high-performing triple-cation (PCE approximate to 20%). The results are also cross-checked on vacuum-processed MAPbI(3) devices. From this analysis, general guidelines on how to optimize a TL are introduced and especially a new and simple formula to easily calculate the amount of doping necessary to counterbalance the low mobility of the TLs.
KW  - perovskite solar cells
KW  - transport layers
KW  - conductivity
KW  - doping
KW  - charge transport
Y1  - 2019
U6  - https://doi.org/10.1021/acsaem.9b00856
SN  - 2574-0962
VL  - 2
IS  - 9
SP  - 6280
EP  - 6287
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Tubiana, C.
A1  - Rinaldi, G.
A1  - Guettler, C.
A1  - Snodgrass, C.
A1  - Shi, X.
A1  - Hu, X.
A1  - Marschall, R.
A1  - Fulle, M.
A1  - Bockeele-Morvan, D.
A1  - Naletto, G.
A1  - Capaccioni, F.
A1  - Sierks, H.
A1  - Arnold, G.
A1  - Barucci, M. A.
A1  - Bertaux, J-L
A1  - Bertini, I
A1  - Bodewits, D.
A1  - Capria, M. T.
A1  - Ciarniello, M.
A1  - Cremonese, G.
A1  - Crovisier, J.
A1  - Da Deppo, V
A1  - Debei, S.
A1  - De Cecco, M.
A1  - Deller, J.
A1  - De Sanctis, M. C.
A1  - Davidsson, B.
A1  - Doose, L.
A1  - Erard, S.
A1  - Filacchione, G.
A1  - Fink, U.
A1  - Formisano, M.
A1  - Fornasier, S.
A1  - Gutierrez, P. J.
A1  - Ip, W-H
A1  - Ivanovski, S.
A1  - Kappel, David
A1  - Keller, H. U.
A1  - Kolokolova, L.
A1  - Koschny, D.
A1  - Krueger, H.
A1  - La Forgia, F.
A1  - Lamy, P. L.
A1  - Lara, L. M.
A1  - Lazzarin, M.
A1  - Levasseur-Regourd, A. C.
A1  - Lin, Z-Y
A1  - Longobardo, A.
A1  - Lopez-Moreno, J. J.
A1  - Marzari, F.
A1  - Migliorini, A.
A1  - Mottola, S.
A1  - Rodrigo, R.
A1  - Taylor, F.
A1  - Toth, I
A1  - Zakharov, V
T1  - Diurnal variation of dust and gas production in comet 67P/Churyumov-Gerasimenko at the inbound equinox as seen by OSIRIS and VIRTIS-M on board Rosetta
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. On 27 April 2015, when comet 67P/Churyumov-Gerasimenko was at 1.76 au from the Sun and moving toward perihelion, the OSIRIS and VIRTIS-M instruments on board the Rosetta spacecraft simultaneously observed the evolving dust and gas coma during a complete rotation of the comet. Aims. We aim to characterize the spatial distribution of dust, H2O, and CO2 gas in the inner coma. To do this, we performed a quantitative analysis of the release of dust and gas and compared the observed H2O production rate with the rate we calculated using a thermophysical model. Methods. For this study we selected OSIRIS WAC images at 612 nm (dust) and VIRTIS-M image cubes at 612 nm, 2700 nm (H2O emission band), and 4200 nm (CO2 emission band). We measured the average signal in a circular annulus to study the spatial variation around the comet, and in a sector of the annulus to study temporal variation in the sunward direction with comet rotation, both at a fixed distance of 3.1 km from the comet center. Results. The spatial correlation between dust and water, both coming from the sunlit side of the comet, shows that water is the main driver of dust activity in this time period. The spatial distribution of CO2 is not correlated with water and dust. There is no strong temporal correlation between the dust brightness and water production rate as the comet rotates. The dust brightness shows a peak at 0 degrees subsolar longitude, which is not pronounced in the water production. At the same epoch, there is also a maximum in CO2 production. An excess of measured water production with respect to the value calculated using a simple thermophysical model is observed when the head lobe and regions of the southern hemisphere with strong seasonal variations are illuminated (subsolar longitude 270 degrees-50 degrees). A drastic decrease in dust production when the water production (both measured and from the model) displays a maximum occurs when typical northern consolidated regions are illuminated and the southern hemisphere regions with strong seasonal variations are instead in shadow (subsolar longitude 50 degrees-90 degrees). Possible explanations of these observations are presented and discussed.
KW  - comets: general
KW  - comets: individual: 67P/Churyumov-Gerasimenko
KW  - methods: data analysis
Y1  - 2019
U6  - https://doi.org/10.1051/0004-6361/201834869
SN  - 1432-0746
VL  - 630
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Rinaldi, G.
A1  - Formisano, M.
A1  - Kappel, David
A1  - Capaccioni, F.
A1  - Bockelee-Morvan, D.
A1  - Cheng, Y-C
A1  - Vincent, J-B
A1  - Deshapriya, P.
A1  - Arnold, G.
A1  - Capria, M. T.
A1  - Ciarniello, M.
A1  - De Sanctis, M. C.
A1  - Doose, L.
A1  - Erard, S.
A1  - Federico, C.
A1  - Filacchione, G.
A1  - Fink, U.
A1  - Leyrat, C.
A1  - Longobardo, A.
A1  - Magni, G.
A1  - Mighorini, A.
A1  - Mottola, S.
A1  - Naletto, G.
A1  - Raponi, A.
A1  - Taylor, F.
A1  - Tosi, F.
A1  - Tozzi, G. P.
A1  - Salatti, M.
T1  - Analysis of night-side dust activity on comet 67P observed by VIRTIS-M
BT  - a new method to constrain the thermal inertia on the surface
JF  - Astronomy and astrophysics : an international weekly journal
N2  - On 2015 July 18, near perihelion at a heliocentric distance of 1.28 au, the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS-M) on board the Rosetta spacecraft had the opportunity of observing dust activity in the inner coma with a view of the night side (shadowed side) of comet 67P/Churyumov-Gerasimenko. At the time of the measurements we present here, we observe a dust plume that originates on the far side of the nucleus. We are able to identify the approximate location of its source at the boundary between the Hapi and Anuket regions, and we find that it has been in darkness for some hours before the observation. Assuming that this time span is equal to the conductive time scale, we obtain a thermal inertia in the range 25-36 W K-1 m(-2) s(-1/2). These thermal inertia values can be used to verify with a 3D finite-element method (REM) numerical code whether the surface and subsurface temperatures agree with the values found in the literature. We explored three different configurations: (1) a layer of water ice mixed with dust beneath a dust mantle of 5 mm with thermal inertia of 36 J m(-2) K-1 S-0.5 ; (2) the same structure, but with thermal inertia of 100 J m(-2) K-1 S-0.5; (3) an ice-dust mixture that is directly exposed. Of these three configurations, the first seems to be the most reasonable, both for the low thermal inertia and for the agreement with the surface and subsurface temperatures that have been found for the comet 67P/Churyumov-Gerasimenko. The spectral properties of the plume show that the visible dust color ranged from 16 +/- 4.8%/100 nm to 13 +/- 2.6%/100 nm, indicating that this plume has no detectable color gradient. The morphology of the plume can be classified as a narrow jet that has an estimated total ejected mass of between 6 and 19 tons when we assume size distribution indices between -2.5 and -3.
KW  - comets: general
KW  - comets: individual: 67P/Churyumov-Gerasimenko
KW  - infrared: planetary systems
Y1  - 2019
U6  - https://doi.org/10.1051/0004-6361/201834907
SN  - 1432-0746
VL  - 630
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Schaffenroth, Veronika
A1  - Barlow, Brad N.
A1  - Geier, Stephan
A1  - Vuckovic, Maja
A1  - Kilkenny, D.
A1  - Wolz, M.
A1  - Kupfer, Thomas
A1  - Heber, Ulrich
A1  - Drechsel, H.
A1  - Kimeswenger, S.
A1  - Marsh, T.
A1  - Wolf, M.
A1  - Pelisoli, Ingrid Domingos
A1  - Freudenthal, Joseph
A1  - Dreizler, S.
A1  - Kreuzer, S.
A1  - Ziegerer, E.
T1  - The EREBOS project: Investigating the effect of substellar and low-mass stellar companions on late stellar evolution Survey, target selection, and atmospheric parameters
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Eclipsing post-common-envelope binaries are highly important for resolving the poorly understood, very short-lived common-envelope phase of stellar evolution. Most hot subdwarfs (sdO/Bs) are the bare helium-burning cores of red giants that have lost almost all of their hydrogen envelope. This mass loss is often triggered by common-envelope interactions with close stellar or even substellar companions. Cool companions to hot subdwarf stars such as late-type stars and brown dwarfs are detectable from characteristic light-curve variations - reflection effects and often eclipses. In the recently published catalog of eclipsing binaries in the Galactic Bulge and in the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey, we discovered 125 new eclipsing systems showing a reflection effect seen by visual inspection of the light curves and using a machine-learning algorithm, in addition to the 36 systems previously discovered by the Optical Gravitational Lesing Experiment (OGLE) team. The Eclipsing Reflection Effect Binaries from Optical Surveys (EREBOS) project aims at analyzing all newly discovered eclipsing binaries of the HW Vir type (hot subdwarf + close, cool companion) based on a spectroscopic and photometric follow up to derive the mass distribution of the companions, constrain the fraction of substellar companions, and determine the minimum mass needed to strip off the red-giant envelope. To constrain the nature of the primary we derived the absolute magnitude and the reduced proper motion of all our targets with the help of the parallaxes and proper motions measured by the Gaia mission and compared those to the Gaia white-dwarf candidate catalog. It was possible to derive the nature of a subset of our targets, for which observed spectra are available, by measuring the atmospheric parameter of the primary, confirming that less than 10% of our systems are not sdO/Bs with cool companions but are white dwarfs or central stars of planetary nebula. This large sample of eclipsing hot subdwarfs with cool companions allowed us to derive a significant period distribution for hot subdwarfs with cool companions for the first time showing that the period distribution is much broader than previously thought and is ideally suited to finding the lowest-mass companions to hot subdwarf stars. The comparison with related binary populations shows that the period distribution of HW Vir systems is very similar to WD+dM systems and central stars of planetary nebula with cool companions. In the future, several new photometric surveys will be carried out, which will further increase the sample of this project, providing the potential to test many aspects of common-envelope theory and binary evolution.
KW  - binaries: eclipsing
KW  - brown dwarfs
KW  - binaries: spectroscopic
KW  - binaries: close
KW  - subdwarfs
KW  - surveys
Y1  - 2019
U6  - https://doi.org/10.1051/0004-6361/201936019
SN  - 1432-0746
VL  - 630
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Mehrabi, Pedram
A1  - Schulz, Eike C.
A1  - Dsouza, Raison
A1  - Müller-Werkmeister, Henrike
A1  - Tellkamp, Friedjof
A1  - Miller, R. J. Dwayne
A1  - Pai, Emil F.
T1  - Time-resolved crystallography reveals allosteric communication aligned with molecular breathing
JF  - Science
N2  - A comprehensive understanding of protein function demands correlating structure and dynamic changes. Using time-resolved serial synchrotron crystallography, we visualized half-of-the-sites reactivity and correlated molecular-breathing motions in the enzyme fluoroacetate dehalogenase. Eighteen time points from 30 milliseconds to 30 seconds cover four turnover cycles of the irreversible reaction. They reveal sequential substrate binding, covalent-intermediate formation, setup of a hydrolytic water molecule, and product release. Small structural changes of the protein mold and variations in the number and placement of water molecules accompany the various chemical steps of catalysis. Triggered by enzyme-ligand interactions, these repetitive changes in the protein framework’s dynamics and entropy constitute crucial components of the catalytic machinery.
Y1  - 2019
U6  - https://doi.org/10.1126/science.aaw9904
SN  - 0036-8075
SN  - 1095-9203
VL  - 365
IS  - 6458
SP  - 1167
EP  - 1170
PB  - American Assoc. for the Advancement of Science
CY  - Washington
ER  - 
TY  - JOUR
A1  - Deb, Marwan
A1  - Popova, Elena
A1  - Hehn, Michel
A1  - Keller, Niels
A1  - Petit-Watelot, Sebastien
A1  - Bargheer, Matias
A1  - Mangin, Stephane
A1  - Malinowski, Gregory
T1  - Damping of Standing Spin Waves in Bismuth-Substituted Yttrium Iron Garnet as Seen via the Time-Resolved Magneto-Optical Kerr Effect
JF  - Physical review applied
N2  - We investigate spin-wave resonance modes and their damping in insulating thin films of bismuth-substituted yttrium iron garnet by performing femtosecond magneto-optical pump-probe experiments. For large magnetic fields in the range below the magnetization saturation, we find that the damping of high-order standing spin-wave (SSW) modes is about 40 times lower than that for the fundamental one. The observed phenomenon can be explained by considering different features of magnetic anisotropy and exchange fields that, respectively, define the precession frequency for fundamental and high-order SSWs. These results provide further insight into SSWs in iron garnets and may be exploited in many new photomagnonic devices.
Y1  - 2019
U6  - https://doi.org/10.1103/PhysRevApplied.12.044006
SN  - 2331-7019
VL  - 12
IS  - 4
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - GEN
A1  - Lazarian, Alexander
A1  - Yan, Huirong
T1  - Erratum: Superdiffusion of Cosmic Rays: Implications for Cosmic Ray Acceleration (The American Astronomical Society. - Vol. 784, (2014), 38)
T2  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - Diffusion of cosmic rays (CRs) is the key process for understanding their propagation and acceleration. We employ the description of spatial separation of magnetic field lines in magnetohydrodynamic turbulence in Lazarian & Vishniac to quantify the divergence of the magnetic field on scales less than the injection scale of turbulence and show that this divergence induces superdiffusion of CR in the direction perpendicular to the mean magnetic field. The perpendicular displacement squared increases, not as the distance x along the magnetic field, which is the case for a regular diffusion, but as the x 3 for freely streaming CRs. The dependence changes to x 3/2 for the CRs propagating diffusively along the magnetic field. In the latter case, we show that it is important to distinguish the perpendicular displacement with respect to the mean field and to the local magnetic field. We consider how superdiffusion changes the acceleration of CRs in shocks and show how it decreases efficiency of the CRs acceleration in perpendicular shocks. We also demonstrate that in the case when the small-scale magnetic field is generated in the pre-shock region, an efficient acceleration can take place for the CRs streaming without collisions along the magnetic loops.
Y1  - 2019
U6  - https://doi.org/10.3847/1538-4357/ab50ba
SN  - 0004-637X
SN  - 1538-4357
VL  - 885
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Pittarello, Lidia
A1  - Goderis, Steven
A1  - Soens, Bastien
A1  - McKibbin, Seann J.
A1  - Giuli, Gabriele
A1  - Bariselli, Federico
A1  - Dias, Bruno
A1  - Helber, Bernd
A1  - Lepore, Giovanni Orazio
A1  - Vanhaecke, Frank
A1  - Köberl, Christian
A1  - Magin, Thierry E.
A1  - Claeys, Philippe
T1  - Meteoroid atmospheric entry investigated with plasma flow experiments: Petrography and geochemistry of the recovered material
JF  - Icarus : international journal of solar system studies
N2  - Melting experiments attempting to reproduce some of the processes affecting asteroidal and cometary material during atmospheric entry have been performed in a high enthalpy facility. For the first time with the specific experimental setup, the resulting material has been recovered, studied, and compared with natural analogues, focusing on the thermal and redox reactions triggered by interaction between the melt and the atmospheric gases under high temperature and low pressure conditions. Experimental conditions were tested across a range of parameters, such as heat flux, experiment duration, and pressure, using two types of sample holders materials, namely cork and graphite. A basalt served as asteroidal analog and to calibrate the experiments, before melting a H5 ordinary chondrite meteorite. The quenched melt recovered after the experiments has been analyzed by mu-XRF, EDS-SEM, EMPA, LA-ICP-MS, and XANES spectroscopy. The glass formed from the basalt is fairly homogeneous, depleted in highly volatile elements (e.g., Na, K), relatively enriched in moderately siderophile elements (e.g., Co, Ni), and has reached an equilibrium redox state with a lower Fe3+/Fe-tot ratio than that in the starting material. Spherical objects, enriched in SiO2, Na2O and K2O, were observed, inferring condensation from the vaporized material. Despite instantaneous quenching, the melt formed from the ordinary chondrite shows extensive crystallization of mostly olivine and magnetite, the latter indicative of oxygen fugacity compatible with presence of both Fe2+ and Fe3+. Similar features have been observed in natural meteorite fusion crusts and in micrometeorites, implying that, at least in terms of maximum temperature reached and chemical reactions, the experiments have successfully reproduced the conditions likely encountered by extraterrestrial material following atmospheric entry.
KW  - Melting experiments
KW  - Atmospheric entry
KW  - Meteorites
KW  - Fusion crust
KW  - Redox
Y1  - 2019
U6  - https://doi.org/10.1016/j.icarus.2019.04.033
SN  - 0019-1035
SN  - 1090-2643
VL  - 331
SP  - 170
EP  - 178
PB  - Elsevier
CY  - San Diego
ER  - 
TY  - JOUR
A1  - Abeysekara, A. U.
A1  - Archer, A.
A1  - Benbow, Wystan
A1  - Bird, Ralph
A1  - Brill, A.
A1  - Brose, Robert
A1  - Buchovecky, M.
A1  - Calderon-Madera, D.
A1  - Christiansen, J. L.
A1  - Cui, W.
A1  - Daniel, M. K.
A1  - Falcone, A.
A1  - Feng, Q.
A1  - Fernandez-Alonso, M.
A1  - Finley, J. P.
A1  - Fortson, Lucy
A1  - Furniss, Amy
A1  - Gent, A.
A1  - Giuri, C.
A1  - Gueta, O.
A1  - Hanna, David
A1  - Hassan, T.
A1  - Hervet, Oliver
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Johnson, Caitlin A.
A1  - Kaaret, P.
A1  - Kertzman, M.
A1  - Kieda, David
A1  - Krause, Maria
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Maier, Gernot
A1  - Moriarty, P.
A1  - Mukherjee, Reshmi
A1  - Nievas-Rosillo, M.
A1  - Ong, R. A.
A1  - Pfrang, Konstantin Johannes
A1  - Pohl, Martin
A1  - Prado, R. R.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Ribeiro, D.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rovero, A. C.
A1  - Sadeh, Iftach
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, Karlen
A1  - Sushch, Iurii
A1  - Svraka, T.
A1  - Weinstein, A.
A1  - Wells, R. M.
A1  - Wilcox, Patrick
A1  - Wilhelm, Alina
A1  - Williams, David Arnold
A1  - Williamson, T. J.
A1  - Zitzer, B.
T1  - Measurement of the Extragalactic Background Light Spectral Energy Distribution with VERITAS
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - The extragalactic background light (EBL), a diffuse photon field in the optical and infrared range, is a record of radiative processes over the universe?s history. Spectral measurements of blazars at very high energies (>100 GeV) enable the reconstruction of the spectral energy distribution (SED) of the EBL, as the blazar spectra are modified by redshift- and energy-dependent interactions of the gamma-ray photons with the EBL. The spectra of 14 VERITAS-detected blazars are included in a new measurement of the EBL SED that is independent of EBL SED models. The resulting SED covers an EBL wavelength range of 0.56?56 ?m, and is in good agreement with lower limits obtained by assuming that the EBL is entirely due to radiation from cataloged galaxies.
KW  - Extragalactic astronomy
KW  - Active galactic nuclei
KW  - Diffuse radiation
KW  - Cosmology
Y1  - 2019
U6  - https://doi.org/10.3847/1538-4357/ab4817
SN  - 0004-637X
SN  - 1538-4357
VL  - 885
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Soupiona, Ourania
A1  - Samaras, Stefanos
A1  - Ortiz-Amezcua, Pablo
A1  - Böckmann, Christine
A1  - Papayannis, Alexandros D.
A1  - Moreira, Gregori De Arruda
A1  - Benavent-Oltra, Jose Antonio
A1  - Guerrero-Rascado, Juan Luis
A1  - Bedoya-Velásquez, Andres Esteban
A1  - Olmo-Reyes, Francisco José
A1  - Román, Roberto
A1  - Kokkalis, Panagiotis
A1  - Mylonaki, Maria
A1  - Alados-Arboledas, Lucas
A1  - Papanikolaou, Christina Anna
A1  - Foskinis, Romanos
T1  - Retrieval of optical and microphysical properties of transported Saharan dust over Athens and Granada based on multi-wavelength Raman lidar measurements: Study of the mixing processes
JF  - Atmospheric environment : air pollution ; emissions, transport and dispersion, transformation, deposition effects, micrometeorology, urban atmosphere, global atmosphere
N2  - In this paper we extract the aerosol microphysical properties for a collection of mineral dust cases measured by multi-wavelength depolarization Raman lidar systems located at the National Technical University of Athens (NTUA, Athens, Greece) and the Andalusian Institute for Earth System Research (IISTA-CEAMA, Granada, Spain). The lidar-based retrievals were carried out with the Spheroidal Inversion eXperiments software tool (SphInX) developed at the University of Potsdam (Germany). The software uses regularized inversion of a two-dimensional enhancement of the Mie model based on the spheroid-particle approximation with the aspect ratio determining the particle shape. The selection of the cases was based on the transport time from the source regions to the measuring sites. The aerosol optical depth as measured by AERONET ranged from 0.27 to 0.54 (at 500 nm) depending on the intensity of each event. Our analysis showed the hourly mean particle linear depolarization ratio and particle lidar ratio values at 532 nm ranging from 11 to 34% and from 42 to 79 sr respectively, depending on the mixing status, the corresponding air mass pathways and their transport time. Cases with shorter transport time showed good agreement in terms of the optical and SphInX-retrieved microphysical properties between Athens and Granada providing a complex refractive index value equal to 1.4 + 0.004i. On the other hand, the results for cases with higher transport time deviated from the aforementioned ones as well as from each other, providing, in particular, an imaginary part of the refractive index ranging from 0.002 to 0.005. Reconstructions of two-dimensional shape-size distributions for each selected layer showed that the dominant effective particle shape was prolate with diverse spherical contributions. The retrieved volume concentrations reflect overall the intensity of the episodes.
Y1  - 2019
U6  - https://doi.org/10.1016/j.atmosenv.2019.116824
SN  - 1352-2310
SN  - 1873-2844
VL  - 214
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Baran, Andrzej S.
A1  - Telting, J. H.
A1  - Jeffery, C. Simon
A1  - Ostensen, R. H.
A1  - Vos, Joris
A1  - Reed, M. D.
A1  - Vŭcković, Maja
T1  - K2 observations of the sdBV plus dM/bd binaries PHL457 and EQPsc
JF  - Monthly notices of the Royal Astronomical Society
N2  - We present an analysis of two pulsating subdwarf B stars PHL 457 and EQ Psc observed during the K2 mission. The K2 light curves of both stars show variation consistent with irradiation of a cooler companion by the hot subdwarf. They also show higher frequency oscillations consistent with pulsation. Using new spectroscopic data, we measured the radial velocity, effective temperature, surface gravity, and helium abundance of both hot subdwarfs as a function of orbital phase. We confirm the previously published spectroscopic orbit of PHL 457, and present the first spectroscopic orbit of EQ Psc. The orbital periods are 0.313 and 0.801 d, respectively. For EQPsc, we find a strong correlation between T-eff and orbital phase, due to contribution of light from the irradiated companion. We calculated amplitude spectra, identified significant pulsation frequencies, and searched for multiplets and asymptotic period spacings. By means of multiplets and period spacing, we identified the degrees of several pulsation modes in each star. The g-mode multiplets indicate subsynchronous core rotation with periods of 4.6 d (PHL 457) and 9.4 d (EQ Psc). We made spectral energy disctribution (SED) fits of PHL 457 and EQ Psc using available broad-band photometry and Gaia data. While the SED of PHL 457 shows no evidence of a cool companion, the SED for EQPsc clearly shows an infrared (IR) access consistent with a secondary with a temperature of about 6800K and a radius of 0.23 R-circle dot. This is the first detection of an IR access in any sdB + dM binary.
KW  - binaries: general
KW  - stars: individual (PHL 457, EQ Psc)
KW  - stars: oscillations (including pulsations)
Y1  - 2019
U6  - https://doi.org/10.1093/mnras/stz2209
SN  - 0035-8711
SN  - 1365-2966
VL  - 489
IS  - 2
SP  - 1556
EP  - 1571
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Eliazar, Iddo
A1  - Metzler, Ralf
A1  - Reuveni, Shlomi
T1  - Poisson-process limit laws yield Gumbel max-min and min-max
JF  - Physical review : E, Statistical, nonlinear and soft matter physics
N2  - “A chain is only as strong as its weakest link” says the proverb. But what about a collection of statistically identical chains: How long till all chains fail? The answer to this question is given by the max-min of a matrix whose (i,j)entry is the failure time of link j of chain i: take the minimum of each row, and then the maximum of the rows' minima. The corresponding min-max is obtained by taking the maximum of each column, and then the minimum of the columns' maxima. The min-max applies to the storage of critical data. Indeed, consider multiple backup copies of a set of critical data items, and consider the (i,j) matrix entry to be the time at which item j on copy i is lost; then, the min-max is the time at which the first critical data item is lost. In this paper we address random matrices whose entries are independent and identically distributed random variables. We establish Poisson-process limit laws for the row's minima and for the columns' maxima. Then, we further establish Gumbel limit laws for the max-min and for the min-max. The limit laws hold whenever the entries' distribution has a density, and yield highly applicable approximation tools and design tools for the max-min and min-max of large random matrices. A brief of the results presented herein is given in: Gumbel central limit theorem for max-min and min-max
Y1  - 2019
U6  - https://doi.org/10.1103/PhysRevE.100.022129
SN  - 2470-0045
SN  - 2470-0053
VL  - 100
IS  - 2
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Eliazar, Iddo
A1  - Metzler, Ralf
A1  - Reuveni, Shlomi
T1  - Gumbel central limit theorem for max-min and min-max
JF  - Physical review : E, Statistical, nonlinear and soft matter physics
N2  - The max-min and min-max of matrices arise prevalently in science and engineering. However, in many real-world situations the computation of the max-min and min-max is challenging as matrices are large and full information about their entries is lacking. Here we take a statistical-physics approach and establish limit laws—akin to the central limit theorem—for the max-min and min-max of large random matrices. The limit laws intertwine random-matrix theory and extreme-value theory, couple the matrix dimensions geometrically, and assert that Gumbel statistics emerge irrespective of the matrix entries' distribution. Due to their generality and universality, as well as their practicality, these results are expected to have a host of applications in the physical sciences and beyond.
Y1  - 2019
U6  - https://doi.org/10.1103/PhysRevE.100.020104
SN  - 2470-0045
SN  - 2470-0053
VL  - 100
IS  - 2
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - GEN
A1  - Niskanen, Johannes
A1  - Fondell, Mattis
A1  - Sahle, Christoph J.
A1  - Eckert, Sebastian
A1  - Jay, Raphael Martin
A1  - Gilmore, Keith
A1  - Pietzsch, Annette
A1  - Dantz, Marcus
A1  - Lu, Xingye
A1  - McNally, Daniel E.
A1  - Schmitt, Thorsten
A1  - Vaz da Cruz, Vinicius
A1  - Kimberg, Victor
A1  - Föhlisch, Alexander
T1  - Reply to Pettersson et al.: Why X-ray spectral features are compatible to continuous distribution models in ambient water
T2  - Proceedings of the National Academy of Sciences of the United States of America
Y1  - 2019
U6  - https://doi.org/10.1073/pnas.1909551116
SN  - 0027-8424
VL  - 116
IS  - 35
SP  - 17158
EP  - 17159
PB  - National Acad. of Sciences
CY  - Washington
ER  - 
TY  - JOUR
A1  - Erdmann, Maren
A1  - Kupsch, Andreas
A1  - Müller, Bernd Randolf
A1  - Hentschel, Manfred P.
A1  - Niebergall, Ute
A1  - Böhning, Martin
A1  - Bruno, Giovanni
T1  - Diesel-induced transparency of plastically deformed high-density polyethylene
JF  - Journal of materials science
N2  - High-density polyethylene becomes optically transparent during tensile drawing when previously saturated with diesel fuel. This unusual phenomenon is investigated as it might allow conclusions with respect to the material behavior. Microscopy, differential scanning calorimetry, density measurements are applied together with two scanning X-ray scattering techniques: wide angle X-ray scattering (WAXS) and X-ray refraction, able to extract the spatially resolved crystal orientation and internal surface, respectively. The sorbed diesel softens the material and significantly alters the yielding characteristics. Although the crystallinity among stretched regions is similar, a virgin reference sample exhibits strain whitening during stretching, while the diesel-saturated sample becomes transparent. The WAXS results reveal a pronounced fiber texture in the tensile direction in the stretched region and an isotropic orientation in the unstretched region. This texture implies the formation of fibrils in the stretched region, while spherulites remain intact in the unstretched parts of the specimens. X-ray refraction reveals a preferred orientation of internal surfaces along the tensile direction in the stretched region of virgin samples, while the sample stretched in the diesel-saturated state shows no internal surfaces at all. Besides from stretching saturated samples, optical transparency is also obtained from sorbing samples in diesel after stretching.
Y1  - 2019
U6  - https://doi.org/10.1007/s10853-019-03700-8
SN  - 0022-2461
SN  - 1573-4803
VL  - 54
IS  - 17
SP  - 11739
EP  - 11755
PB  - Springer
CY  - New York
ER  -