TY - JOUR A1 - De Becker, M. A1 - del Valle, Maria Victoria A1 - Romero, G. E. A1 - Peri, C. S. A1 - Benaglia, P. T1 - X- ray study of bow shocks in runaway stars JF - Monthly notices of the Royal Astronomical Society N2 - Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of five bow shock runaways, which constitutes a significant improvement of the sample of bow shock runaways studied in X-rays so far. A careful analysis of the data did not reveal any X-ray emission related to the bow shocks. However, X-ray emission from the stars is detected, in agreement with the expected thermal emission from stellar winds. On the basis of background measurements we derive conservative upper limits between 0.3 and 10 keV on the bow shocks emission. Using a simple radiation model, these limits together with radio upper limits allow us to constrain some of the main physical quantities involved in the non-thermal emission processes, such as the magnetic field strength and the amount of incident infrared photons. The reasons likely responsible for the non-detection of non-thermal radiation are discussed. Finally, using energy budget arguments, we investigate the detectability of inverse Compton X-rays in a more extended sample of catalogued runaway star bow shocks. From our analysis we conclude that a clear identification of non-thermal X-rays from massive runaway bow shocks requires one order of magnitude (or higher) sensitivity improvement with respect to present observatories. KW - acceleration of particles KW - radiation mechanisms: non-thermal KW - stars: earlytype KW - X-rays: stars Y1 - 2017 U6 - https://doi.org/10.1093/mnras/stx1826 SN - 0035-8711 SN - 1365-2966 VL - 471 SP - 4452 EP - 4464 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Sadovnichii, V. A. A1 - Panasyuk, M. I. A1 - Amelyushkin, A. M. A1 - Bogomolov, V. V. A1 - Benghin, V. V. A1 - Garipov, G. K. A1 - Kalegaev, V. V. A1 - Klimov, P. A. A1 - Khrenov, B. A. A1 - Petrov, V. L. A1 - Sharakin, S. A. A1 - Shirokov, A. V. A1 - Svertilov, S. I. A1 - Zotov, M. Y. A1 - Yashin, I. V. A1 - Gorbovskoy, E. S. A1 - Lipunov, V. M. A1 - Park, I. H. A1 - Lee, J. A1 - Jeong, S. A1 - Kim, M. B. A1 - Jeong, H. M. A1 - Shprits, Yuri Y. A1 - Angelopoulos, V. A1 - Russell, C. T. A1 - Runov, A. A1 - Turner, D. A1 - Strangeway, R. J. A1 - Caron, R. A1 - Biktemerova, S. A1 - Grinyuk, A. A1 - Lavrova, M. A1 - Tkachev, L. A1 - Tkachenko, A. A1 - Martinez, O. A1 - Salazar, H. A1 - Ponce, E. T1 - "Lomonosov" Satellite-Space Observatory to Study Extreme Phenomena in Space JF - Space science reviews N2 - The "Lomonosov" space project is lead by Lomonosov Moscow State University in collaboration with the following key partners: Joint Institute for Nuclear Research, Russia, University of California, Los Angeles (USA), University of Pueblo (Mexico), Sungkyunkwan University (Republic of Korea) and with Russian space industry organi-zations to study some of extreme phenomena in space related to astrophysics, astroparticle physics, space physics, and space biology. The primary goals of this experiment are to study: -Ultra-high energy cosmic rays (UHECR) in the energy range of the Greizen-ZatsepinKuzmin (GZK) cutoff; -Ultraviolet (UV) transient luminous events in the upper atmosphere; -Multi-wavelength study of gamma-ray bursts in visible, UV, gamma, and X-rays; -Energetic trapped and precipitated radiation (electrons and protons) at low-Earth orbit (LEO) in connection with global geomagnetic disturbances; -Multicomponent radiation doses along the orbit of spacecraft under different geomagnetic conditions and testing of space segments of optical observations of space-debris and other space objects; -Instrumental vestibular-sensor conflict of zero-gravity phenomena during space flight. This paper is directed towards the general description of both scientific goals of the project and scientific equipment on board the satellite. The following papers of this issue are devoted to detailed descriptions of scientific instruments. KW - Gamma-ray bursts KW - Ultra-high energy cosmic rays KW - Radiation belts KW - Space mission Y1 - 2017 U6 - https://doi.org/10.1007/s11214-017-0425-x SN - 0038-6308 SN - 1572-9672 VL - 212 SP - 1705 EP - 1738 PB - Springer CY - Dordrecht ER - TY - GEN A1 - Shprits, Yuri Y. T1 - Editorial: Topical Collection on the Lomonosov Mission T2 - Space science reviews Y1 - 2017 U6 - https://doi.org/10.1007/s11214-017-0393-1 SN - 0038-6308 SN - 1572-9672 VL - 212 SP - 1685 EP - 1686 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Abeysekara, A. U. A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Brose, Robert A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Cerruti, M. A1 - Connolly, M. P. A1 - Cui, W. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Huetten, M. A1 - Hanna, D. A1 - Hervet, O. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Petrashyk, A. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rulten, C. A1 - Sadeh, I. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tyler, J. A1 - Vassiliev, V. V. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Wilcox, P. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. T1 - Discovery of Very-high-energy Emission from RGB J2243+203 and Derivation of Its Redshift Upper Limit JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series N2 - Very-high-energy (VHE; > 100 GeV) gamma-ray emission from the blazar RGB J2243+203 was discovered with the VERITAS Cherenkov telescope array, during the period between 2014 December 21 and 24. The VERITAS energy spectrum from this source can be fitted by a power law with a photon index of 4.6 +/- 0.5, and a flux normalization at 0.15 TeV of (6.3 +/- 1.1) x 10(-10) cm(-2) s(-1) TeV-1. The integrated Fermi-LAT flux from 1 to 100 GeV during the VERITAS detection is (4.1 +/- 0.8) x 10(-8) cm(-2) s(-1), which is an order of magnitude larger than the four-year-averaged flux in the same energy range reported in the 3FGL catalog, (4.0 +/- 0.1 x 10(-9) cm(-2) s(-1)). The detection with VERITAS triggered observations in the X-ray band with the Swift-XRT. However, due to scheduling constraints Swift-XRT observations were performed 67 hr after the VERITAS detection, rather than simultaneously with the VERITAS observations. The observed X-ray energy spectrum between 2 and 10 keV can be fitted with a power law with a spectral index of 2.7 +/- 0.2, and the integrated photon flux in the same energy band is (3.6 +/- 0.6) x 10(-13) cm(-2) s(-1). EBL-model-dependent upper limits of the blazar redshift have been derived. Depending on the EBL model used, the upper limit varies in the range from z < 0.9 to z < 1.1. KW - galaxies: individual (RGB J2243+203) Y1 - 2017 U6 - https://doi.org/10.3847/1538-4365/aa8d76 SN - 0067-0049 SN - 1538-4365 VL - 233 SP - 1188 EP - 1204 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Evsevleev, Sergei A1 - Müller, Bernd R. A1 - Osenberg, Markus A1 - Manke, Ingo A1 - Hentschel, Manfred P. A1 - Bruno, Giovanni T1 - Optimizing the visibility of X-ray phase grating interferometry JF - Materials testing : Materialprüfung ; materials and components, technology and application N2 - The performance of grating interferometers coming up now for imaging interfaces within materials depends on the efficiency (visibility) of their main component, namely the phase grating. Therefore, experiments with monochromatic synchrotron radiation and corresponding simulations are carried out. The visibility of a phase grating is optimized by different photon energies, varying detector to grating distances and continuous rotation of the phase grating about the grid lines. Such kind of rotation changes the projected grating shapes, and thereby the distribution profiles of phase shifts. This yields higher visibilities than derived from ideal rectangular shapes. By continuous grating rotation and variation of the propagation distance, we achieve 2D visibility maps. Such maps provide the visibility for a certain combination of grating orientation and detector position. Optimum visibilities occur at considerably smaller distances than in the standard setup. KW - X-ray imaging KW - grating interferometry KW - Talbot-Lau interferometer KW - X-ray refraction KW - X-ray phase contrast Y1 - 2017 U6 - https://doi.org/10.3139/120.111097 SN - 0025-5300 VL - 59 SP - 974 EP - 980 PB - Hanser CY - München ER - TY - JOUR A1 - Nidever, David L. A1 - Olsen, Knut A1 - Walker, Alistair R. A1 - Katherina Vivas, A. A1 - Blum, Robert D. A1 - Kaleida, Catherine A1 - Choi, Yumi A1 - Conn, Blair C. A1 - Gruendl, Robert A. A1 - Bell, Eric F. A1 - Besla, Gurtina A1 - Munoz, Ricardo R. A1 - Gallart, Carme A1 - Martin, Nicolas F. A1 - Olszewski, Edward W. A1 - Saha, Abhijit A1 - Monachesi, Antonela A1 - Monelli, Matteo A1 - de Boer, Thomas J. L. A1 - Johnson, L. Clifton A1 - Zaritsky, Dennis A1 - Stringfellow, Guy S. A1 - van der Marel, Roeland P. A1 - Cioni, Maria-Rosa L. A1 - Jin, Shoko A1 - Majewski, Steven R. A1 - Martinez-Delgado, David A1 - Monteagudo, Lara A1 - Noel, Noelia E. D. A1 - Bernard, Edouard J. A1 - Kunder, Andrea A1 - Chu, You-Hua A1 - Bell, Cameron P. M. A1 - Santana, Felipe A1 - Frechem, Joshua A1 - Medina, Gustavo E. A1 - Parkash, Vaishali A1 - Seron Navarrete, J. C. A1 - Hayes, Christian T1 - SMASH: Survey of the MAgellanic Stellar History JF - The astronomical journal N2 - The Large and Small Magellanic Clouds are unique local laboratories for studying the formation and evolution of small galaxies in exquisite detail. The Survey of the MAgellanic Stellar History (SMASH) is an NOAO community Dark Energy Camera (DECam) survey of the Clouds mapping 480 deg2 (distributed over similar to 2400 square degrees at similar to 20% filling factor) to similar to 24th. mag in ugriz. The primary goals of SMASH are to identify low surface brightness stellar populations associated with the stellar halos and tidal debris of the Clouds, and to derive spatially resolved star formation histories. Here, we present a summary of the survey, its data reduction, and a description of the first public Data Release (DR1). The SMASH DECam data have been reduced with a combination of the NOAO Community Pipeline, the PHOTRED automated point-spread-function photometry pipeline, and custom calibration software. The astrometric precision is similar to 15 mas and the accuracy is similar to 2 mas with respect to the Gaia reference frame. The photometric precision is similar to 0.5%-0.7% in griz and similar to 1% in u with a calibration accuracy of similar to 1.3% in all bands. The median 5s point source depths in ugriz are 23.9, 24.8, 24.5, 24.2, and 23.5 mag. The SMASH data have already been used to discover the Hydra II Milky Way satellite, the SMASH 1 old globular cluster likely associated with the LMC, and extended stellar populations around the LMC out to R. similar to. 18.4 kpc. SMASH DR1 contains measurements of similar to 100 million objects distributed in 61 fields. A prototype version of the NOAO Data Lab provides data access and exploration tools. KW - galaxies: dwarf KW - galaxies: individual (Large Magellanic Cloud, Small Magellanic Cloud) KW - Local Group KW - Magellanic Clouds KW - surveys Y1 - 2017 U6 - https://doi.org/10.3847/1538-3881/aa8d1c SN - 0004-6256 SN - 1538-3881 VL - 154 SP - 310 EP - 326 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Delle Side, Domenico A1 - Nassisi, Vincenzo A1 - Pennetta, Cecilia A1 - Alifano, Pietro A1 - Di Salvo, Marco A1 - Tala, Adelfia A1 - Chechkin, Aleksei V. A1 - Seno, Flavio A1 - Trovato, Antonio T1 - Bacterial bioluminescence onset and quenching: a dynamical model for a quorum sensing-mediated property JF - Royal Society Open Science N2 - We present an effective dynamical model for the onset of bacterial bioluminescence, one of the most studied quorum sensing-mediated traits. Our model is built upon simple equations that describe the growth of the bacterial colony, the production and accumulation of autoinducer signal molecules, their sensing within bacterial cells, and the ensuing quorum activation mechanism that triggers bioluminescent emission. The model is directly tested to quantitatively reproduce the experimental distributions of photon emission times, previously measured for bacterial colonies of Vibrio jasicida, a luminescent bacterium belonging to the Harveyi clade, growing in a highly drying environment. A distinctive and novel feature of the proposed model is bioluminescence ‘quenching’ after a given time elapsed from activation. Using an advanced fitting procedure based on the simulated annealing algorithm, we are able to infer from the experimental observations the biochemical parameters used in the model. Such parameters are in good agreement with the literature data. As a further result, we find that, at least in our experimental conditions, light emission in bioluminescent bacteria appears to originate from a subtle balance between colony growth and quorum activation due to autoinducers diffusion, with the two phenomena occurring on the same time scale. This finding is consistent with a negative feedback mechanism previously reported for Vibrio harveyi. KW - quorum sensing KW - bioluminescence KW - biophysical model KW - Vibrio Harveyi clade KW - oxygen quenching KW - Gompertz growth function Y1 - 2017 U6 - https://doi.org/10.1098/rsos.171586 SN - 2054-5703 VL - 4 PB - Royal Society CY - London ER - TY - JOUR A1 - Zhelavskaya, Irina A1 - Shprits, Yuri Y. A1 - Spasojevic, Maria T1 - Empirical Modeling of the Plasmasphere Dynamics Using Neural Networks JF - Journal of geophysical research : Space physics N2 - We present the PINE (Plasma density in the Inner magnetosphere Neural network‐based Empirical) model ‐ a new empirical model for reconstructing the global dynamics of the cold plasma density distribution based only on solar wind data and geomagnetic indices. Utilizing the density database obtained using the NURD (Neural‐network‐based Upper hybrid Resonance Determination) algorithm for the period of 1 October 2012 to 1 July 2016, in conjunction with solar wind data and geomagnetic indices, we develop a neural network model that is capable of globally reconstructing the dynamics of the cold plasma density distribution for 2≤L≤6 and all local times. We validate and test the model by measuring its performance on independent data sets withheld from the training set and by comparing the model‐predicted global evolution with global images of He+ distribution in the Earth's plasmasphere from the IMAGE Extreme UltraViolet (EUV) instrument. We identify the parameters that best quantify the plasmasphere dynamics by training and comparing multiple neural networks with different combinations of input parameters (geomagnetic indices, solar wind data, and different durations of their time history). The optimal model is based on the 96 h time history of Kp, AE, SYM‐H, and F10.7 indices. The model successfully reproduces erosion of the plasmasphere on the nightside and plume formation and evolution. We demonstrate results of both local and global plasma density reconstruction. This study illustrates how global dynamics can be reconstructed from local in situ observations by using machine learning techniques. Y1 - 2017 U6 - https://doi.org/10.1002/2017JA024406 SN - 2169-9380 SN - 2169-9402 VL - 122 SP - 11227 EP - 11244 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Thielemann-Kühn, Nele A1 - Schick, Daniel A1 - Pontius, Niko A1 - Trabant, Christoph A1 - Mitzner, Rolf A1 - Holldack, Karsten A1 - Zabel, Hartmut A1 - Föhlisch, Alexander A1 - Schuessler-Langeheine, Christian T1 - Ultrafast and Energy-Efficient Quenching of Spin Order: Antiferromagnetism Beats Ferromagnetism JF - Physical review letters N2 - By comparing femtosecond laser pulse induced ferro- and antiferromagnetic dynamics in one and the same material-metallic dysprosium-we show both to behave fundamentally different. Antiferromagnetic order is considerably faster and much more efficiently reduced by optical excitation than its ferromagnetic counterpart. We assign the fast and extremely efficient process in the antiferromagnet to an interatomic transfer of angular momentum within the spin system. Our findings imply that this angular momentum transfer channel is effective in other magnetic metals with nonparallel spin alignment. They also point out a possible route towards energy-efficient spin manipulation for magnetic devices. Y1 - 2017 U6 - https://doi.org/10.1103/PhysRevLett.119.197202 SN - 0031-9007 SN - 1079-7114 VL - 119 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Goychuk, Igor T1 - Fractional Bhatnagar-Gross-Krook kinetic equation JF - The European physical journal : B, Condensed matter and complex systems N2 - The linear Boltzmann equation approach is generalized to describe fractional superdiffusive transport of the Levy walk type in external force fields. The time distribution between scattering events is assumed to have a finite mean value and infinite variance. It is completely characterized by the two scattering rates, one fractional and a normal one, which defines also the mean scattering rate. We formulate a general fractional linear Boltzmann equation approach and exemplify it with a particularly simple case of the Bohm and Gross scattering integral leading to a fractional generalization of the Bhatnagar, Gross and Krook kinetic equation. Here, at each scattering event the particle velocity is completely randomized and takes a value from equilibrium Maxwell distribution at a given fixed temperature. We show that the retardation effects are indispensable even in the limit of infinite mean scattering rate and argue that this novel fractional kinetic equation provides a viable alternative to the fractional Kramers-Fokker-Planck (KFP) equation by Barkai and Silbey and its generalization by Friedrich et al. based on the picture of divergent mean time between scattering events. The case of divergent mean time is also discussed at length and compared with the earlier results obtained within the fractional KFP. Also a phenomenological fractional BGK equation without retardation effects is proposed in the limit of infinite scattering rates. It cannot be, however, rigorously derived from a scattering model, being rather clever postulated. It this respect, this retardationless equation is similar to the fractional KFP by Barkai and Silbey. However, it corresponds to the opposite, much more physical limit and, therefore, also presents a viable alternative. Y1 - 2017 U6 - https://doi.org/10.1140/epjb/e2017-80297-x SN - 1434-6028 SN - 1434-6036 VL - 90 PB - Springer CY - New York ER -