TY  - JOUR
A1  - Warren, Donald C.
A1  - Ellison, Donald C.
A1  - Barkov, Maxim V.
A1  - Nagataki, Shigehiro
T1  - Nonlinear Particle Acceleration and Thermal Particles in GRB Afterglows
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - The standard model for GRB afterglow emission treats the accelerated electron population as a simple power law, N(E) proportional to E-p for p greater than or similar to 2. However, in standard Fermi shock acceleration, a substantial fraction of the swept-up particles do not enter the acceleration process at all. Additionally, if acceleration is efficient, then the nonlinear back-reaction of accelerated particles on the shock structure modifies the shape of the nonthermal tail of the particle spectra. Both of these modifications to the standard synchrotron afterglow impact the luminosity, spectra, and temporal variation of the afterglow. To examine the effects of including thermal particles and nonlinear particle acceleration on afterglow emission, we follow a hydrodynamical model for an afterglow jet and simulate acceleration at numerous points during the evolution. When thermal particles are included, we find that the electron population is at no time well fitted by a single power law, though the highest-energy electrons are; if the acceleration is efficient, then the power-law region is even smaller. Our model predicts hard-soft-hard spectral evolution at X-ray energies, as well as an uncoupled X-ray and optical light curve. Additionally, we show that including emission from thermal particles has drastic effects (increases by factors of 100 and 30, respectively) on the observed flux at optical and GeV energies. This enhancement of GeV emission makes afterglow detections by future gamma-ray observatories, such as CTA, very likely.
KW  - acceleration of particles
KW  - cosmic rays
KW  - gamma-ray burst: general
KW  - shock waves
KW  - turbulence
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/aa56c3
SN  - 0004-637X
SN  - 1538-4357
VL  - 835
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Lopez-Barquero, Vanessa
A1  - Xu, S.
A1  - Desiati, Paolo
A1  - Lazarian, Alex
A1  - Pogorelov, Nikolai V.
A1  - Yan, Huirong
T1  - TeV Cosmic-Ray Anisotropy from the Magnetic Field at the Heliospheric Boundary
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
KW  - cosmic rays
KW  - magnetic fields
KW  - magnetohydrodynamics (MHD)
KW  - solar wind
KW  - Sun: heliosphere
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/aa74d1
SN  - 0004-637X
SN  - 1538-4357
VL  - 842
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Acero, F.
A1  - Aloisio, R.
A1  - Amans, J.
A1  - Amato, Elena
A1  - Antonelli, L. A.
A1  - Aramo, C.
A1  - Armstrong, T.
A1  - Arqueros, F.
A1  - Asano, Katsuaki
A1  - Ashley, M.
A1  - Backes, M.
A1  - Balazs, C.
A1  - Balzer, A.
A1  - Bamba, Aya
A1  - Barkov, Maxim
A1  - Barrio, J. A.
A1  - Benbow, Wystan
A1  - Bernloehr, K.
A1  - Beshley, V.
A1  - Bigongiari, C.
A1  - Biland, A.
A1  - Bilinsky, A.
A1  - Bissaldi, Elisabetta
A1  - Biteau, J.
A1  - Blanch, O.
A1  - Blasi, P.
A1  - Blazek, J.
A1  - Boisson, C.
A1  - Bonanno, G.
A1  - Bonardi, A.
A1  - Bonavolonta, C.
A1  - Bonnoli, G.
A1  - Braiding, C.
A1  - Brau-Nogue, S.
A1  - Bregeon, J.
A1  - Brown, A. M.
A1  - Bugaev, V.
A1  - Bulgarelli, A.
A1  - Bulik, T.
A1  - Burton, Michael
A1  - Burtovoi, A.
A1  - Busetto, G.
A1  - Bottcher, M.
A1  - Cameron, R.
A1  - Capalbi, M.
A1  - Caproni, Anderson
A1  - Caraveo, P.
A1  - Carosi, R.
A1  - Cascone, E.
A1  - Cerruti, M.
A1  - Chaty, Sylvain
A1  - Chen, A.
A1  - Chen, X.
A1  - Chernyakova, M.
A1  - Chikawa, M.
A1  - Chudoba, J.
A1  - Cohen-Tanugi, J.
A1  - Colafrancesco, S.
A1  - Conforti, V.
A1  - Contreras, J. L.
A1  - Costa, A.
A1  - Cotter, G.
A1  - Covino, Stefano
A1  - Covone, G.
A1  - Cumani, P.
A1  - Cusumano, G.
A1  - Daniel, M.
A1  - Dazzi, F.
A1  - De Angelis, A.
A1  - De Cesare, G.
A1  - De Franco, A.
A1  - De Frondat, F.
A1  - Dal Pino, E. M. de Gouveia
A1  - De Lisio, C.
A1  - Lopez, R. de los Reyes
A1  - De Lotto, B.
A1  - de Naurois, M.
A1  - De Palma, F.
A1  - Del Santo, M.
A1  - Delgado, C.
A1  - della Volpe, D.
A1  - Di Girolamo, T.
A1  - Di Giulio, C.
A1  - Di Pierro, F.
A1  - Di Venere, L.
A1  - Doro, M.
A1  - Dournaux, J.
A1  - Dumas, D.
A1  - Dwarkadas, Vikram V.
A1  - Diaz, C.
A1  - Ebr, J.
A1  - Egberts, Kathrin
A1  - Einecke, S.
A1  - Elsaesser, D.
A1  - Eschbach, S.
A1  - Falceta-Goncalves, D.
A1  - Fasola, G.
A1  - Fedorova, E.
A1  - Fernandez-Barral, A.
A1  - Ferrand, Gilles
A1  - Fesquet, M.
A1  - Fiandrini, E.
A1  - Fiasson, A.
A1  - Filipovic, Miroslav D.
A1  - Fioretti, V.
A1  - Font, L.
A1  - Fontaine, Gilles
A1  - Franco, F. J.
A1  - Freixas Coromina, L.
A1  - Fujita, Yutaka
A1  - Fukui, Y.
A1  - Funk, S.
A1  - Forster, A.
A1  - Gadola, A.
A1  - Lopez, R. Garcia
A1  - Garczarczyk, M.
A1  - Giglietto, N.
A1  - Giordano, F.
A1  - Giuliani, A.
A1  - Glicenstein, J.
A1  - Gnatyk, R.
A1  - Goldoni, P.
A1  - Grabarczyk, T.
A1  - Graciani, R.
A1  - Graham, J.
A1  - Grandi, P.
A1  - Granot, Jonathan
A1  - Green, A. J.
A1  - Griffiths, S.
A1  - Gunji, S.
A1  - Hakobyan, H.
A1  - Hara, S.
A1  - Hassan, T.
A1  - Hayashida, M.
A1  - Heller, M.
A1  - Helo, J. C.
A1  - Hinton, J.
A1  - Hnatyk, B.
A1  - Huet, J.
A1  - Huetten, M.
A1  - Humensky, T. B.
A1  - Hussein, M.
A1  - Horandel, J.
A1  - Ikeno, Y.
A1  - Inada, T.
A1  - Inome, Y.
A1  - Inoue, S.
A1  - Inoue, T.
A1  - Inoue, Y.
A1  - Ioka, K.
A1  - Iori, Maurizio
A1  - Jacquemier, J.
A1  - Janecek, P.
A1  - Jankowsky, D.
A1  - Jung, I.
A1  - Kaaret, P.
A1  - Katagiri, H.
A1  - Kimeswenger, S.
A1  - Kimura, Shigeo S.
A1  - Knodlseder, J.
A1  - Koch, B.
A1  - Kocot, J.
A1  - Kohri, K.
A1  - Komin, N.
A1  - Konno, Y.
A1  - Kosack, K.
A1  - Koyama, S.
A1  - Kraus, Michaela
A1  - Kubo, Hidetoshi
A1  - Mezek, G. Kukec
A1  - Kushida, J.
A1  - La Palombara, N.
A1  - Lalik, K.
A1  - Lamanna, G.
A1  - Landt, H.
A1  - Lapington, J.
A1  - Laporte, P.
A1  - Lee, S.
A1  - Lees, J.
A1  - Lefaucheur, J.
A1  - Lenain, J. -P.
A1  - Leto, Giuseppe
A1  - Lindfors, E.
A1  - Lohse, T.
A1  - Lombardi, S.
A1  - Longo, F.
A1  - Lopez, M.
A1  - Lucarelli, F.
A1  - Luque-Escamilla, Pedro Luis
A1  - Lopez-Coto, R.
A1  - Maccarone, M. C.
A1  - Maier, G.
A1  - Malaguti, G.
A1  - Mandat, D.
A1  - Maneva, G.
A1  - Mangano, S.
A1  - Marcowith, Alexandre
A1  - Marti, J.
A1  - Martinez, M.
A1  - Martinez, G.
A1  - Masuda, S.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Melioli, Claudio
A1  - Mineo, T.
A1  - Mirabal, N.
A1  - Mizuno, T.
A1  - Moderski, R.
A1  - Mohammed, M.
A1  - Montaruli, T.
A1  - Moralejo, A.
A1  - Mori, K.
A1  - Morlino, G.
A1  - Morselli, A.
A1  - Moulin, Emmanuel
A1  - Mukherjee, R.
A1  - Mundell, C.
A1  - Muraishi, H.
A1  - Murase, Kohta
A1  - Nagataki, Shigehiro
A1  - Nagayoshi, T.
A1  - Naito, T.
A1  - Nakajima, D.
A1  - Nakamori, T.
A1  - Nemmen, R.
A1  - Niemiec, Jacek
A1  - Nieto, D.
A1  - Nievas-Rosillo, M.
A1  - Nikolajuk, M.
A1  - Nishijima, K.
A1  - Noda, K.
A1  - Nogues, L.
A1  - Nosek, D.
A1  - Novosyadlyj, B.
A1  - Nozaki, S.
A1  - Ohira, Yutaka
A1  - Ohishi, M.
A1  - Ohm, S.
A1  - Okumura, A.
A1  - Ong, R. A.
A1  - Orito, R.
A1  - Orlati, A.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Padovani, Marco
A1  - Palacio, J.
A1  - Palatka, M.
A1  - Paredes, Josep M.
A1  - Pavy, S.
A1  - Persic, M.
A1  - Petrucci, P.
A1  - Petruk, Oleh
A1  - Pisarski, A.
A1  - Pohl, Martin
A1  - Porcelli, A.
A1  - Prandini, E.
A1  - Prast, J.
A1  - Principe, G.
A1  - Prouza, M.
A1  - Pueschel, Elisa
A1  - Puelhofer, G.
A1  - Quirrenbach, A.
A1  - Rameez, M.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - Ribo, M.
A1  - Rico, J.
A1  - Rizi, V.
A1  - Rodriguez, J.
A1  - Fernandez, G. Rodriguez
A1  - Rodriguez Vazquez, J. J.
A1  - Romano, Patrizia
A1  - Romeo, G.
A1  - Rosado, J.
A1  - Rousselle, J.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Sadeh, I.
A1  - Safi-Harb, S.
A1  - Saito, T.
A1  - Sakaki, N.
A1  - Sanchez, D.
A1  - Sangiorgi, P.
A1  - Sano, H.
A1  - Santander, M.
A1  - Sarkar, S.
A1  - Sawada, M.
A1  - Schioppa, E. J.
A1  - Schoorlemmer, H.
A1  - Schovanek, P.
A1  - Schussler, F.
A1  - Sergijenko, O.
A1  - Servillat, M.
A1  - Shalchi, A.
A1  - Shellard, R. C.
A1  - Siejkowski, H.
A1  - Sillanpaa, A.
A1  - Simone, D.
A1  - Sliusar, V.
A1  - Sol, H.
A1  - Stanic, S.
A1  - Starling, R.
A1  - Stawarz, L.
A1  - Stefanik, S.
A1  - Stephan, M.
A1  - Stolarczyk, T.
A1  - Szanecki, M.
A1  - Szepieniec, T.
A1  - Tagliaferri, G.
A1  - Tajima, H.
A1  - Takahashi, M.
A1  - Takeda, J.
A1  - Tanaka, M.
A1  - Tanaka, S.
A1  - Tejedor, L. A.
A1  - Telezhinsky, Igor O.
A1  - Temnikov, P.
A1  - Terada, Y.
A1  - Tescaro, D.
A1  - Teshima, M.
A1  - Testa, V.
A1  - Thoudam, S.
A1  - Tokanai, F.
A1  - Torres, D. F.
A1  - Torresi, E.
A1  - Tosti, G.
A1  - Townsley, C.
A1  - Travnicek, P.
A1  - Trichard, C.
A1  - Trifoglio, M.
A1  - Tsujimoto, S.
A1  - Vagelli, V.
A1  - Vallania, P.
A1  - Valore, L.
A1  - van Driel, W.
A1  - van Eldik, C.
A1  - Vandenbroucke, Justin
A1  - Vassiliev, V.
A1  - Vecchi, M.
A1  - Vercellone, Stefano
A1  - Vergani, S.
A1  - Vigorito, C.
A1  - Vorobiov, S.
A1  - Vrastil, M.
A1  - Vazquez Acosta, M. L.
A1  - Wagner, S. J.
A1  - Wagner, R.
A1  - Wakely, S. P.
A1  - Walter, R.
A1  - Ward, J. E.
A1  - Watson, J. J.
A1  - Weinstein, A.
A1  - White, M.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Wilcox, P.
A1  - Williams, D. A.
A1  - Wischnewski, R.
A1  - Wojcik, P.
A1  - Yamamoto, T.
A1  - Yamamoto, H.
A1  - Yamazaki, Ryo
A1  - Yanagita, S.
A1  - Yang, L.
A1  - Yoshida, T.
A1  - Yoshida, M.
A1  - Yoshiike, S.
A1  - Yoshikoshi, T.
A1  - Zacharias, M.
A1  - Zampieri, L.
A1  - Zanin, R.
A1  - Zavrtanik, M.
A1  - Zavrtanik, D.
A1  - Zdziarski, A.
A1  - Zech, Alraune
A1  - Zechlin, Hannes
A1  - Zhdanov, V.
A1  - Ziegler, A.
A1  - Zorn, J.
T1  - Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7-3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti) correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7-3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.
KW  - cosmic rays
KW  - gamma rays: ISM
KW  - ISM: individual objects (RX J1713.7-3946, G347.3-0.5)
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/aa6d67
SN  - 0004-637X
SN  - 1538-4357
VL  - 840
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Fraschetti, F.
A1  - Pohl, Martin
T1  - Particle acceleration model for the broad-band baseline spectrum of the Crab nebula
JF  - Monthly notices of the Royal Astronomical Society
N2  - We develop a simple one-zone model of the steady-state Crab nebula spectrum encompassing both the radio/soft X-ray and the GeV/multi-TeV observations. By solving the transport equation for GeV-TeV electrons injected at the wind termination shock as a log-parabola momentum distribution and evolved via energy losses, we determine analytically the resulting differential energy spectrum of photons. We find an impressive agreement with the observed spectrum of synchrotron emission, and the synchrotron self-Compton component reproduces the previously unexplained broad 200-GeV peak that matches the Fermi/Large Area Telescope (LAT) data beyond 1 GeV with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) data. We determine the parameters of the single log-parabola electron injection distribution, in contrast with multiple broken power-law electron spectra proposed in the literature. The resulting photon differential spectrum provides a natural interpretation of the deviation from power law customarily fitted with empirical multiple broken power laws. Our model can be applied to the radio-to-multi-TeV spectrum of a variety of astrophysical outflows, including pulsar wind nebulae and supernova remnants, as well as to interplanetary shocks.
KW  - acceleration of particles
KW  - shock waves
KW  - cosmic rays
KW  - ISM: supernova remnants
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx1833
SN  - 0035-8711
SN  - 1365-2966
VL  - 471
SP  - 4866
EP  - 4874
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Kobzar, Oleh
A1  - Niemiec, Jacek
A1  - Pohl, Martin
A1  - Bohdan, Artem
T1  - Spatio-temporal evolution of the non-resonant instability in shock precursors of young supernova remnants
JF  - Monthly notices of the Royal Astronomical Society
N2  - A non-resonant cosmic ray (CR) current-driven instability may operate in the shock precursors of young supernova remnants and be responsible for magnetic-field amplification, plasma heating and turbulence. Earlier simulations demonstrated magnetic-field amplification, and in kinetic studies a reduction of the relative drift between CRs and thermal plasma was observed as backreaction. However, all published simulations used periodic boundary conditions, which do not account for mass conservation in decelerating flows and only allow the temporal development to be studied. Here we report results of fully kinetic particle-in-cell simulations with open boundaries that permit inflow of plasma on one side of the simulation box and outflow at the other end, hence allowing an investigation of both the temporal and the spatial development of the instability. Magnetic-field amplification proceeds as in studies with periodic boundaries and, observed here for the first time, the reduction of relative drifts causes the formation of a shock-like compression structure at which a fraction of the plasma ions are reflected. Turbulent electric field generated by the non-resonant instability inelastically scatters CRs, modifying and anisotropizing their energy distribution. Spatial CR scattering is compatible with Bohm diffusion. Electromagnetic turbulence leads to significant non-adiabatic heating of the background plasma maintaining bulk equipartition between ions and electrons. The highest temperatures are reached at sites of large-amplitude electrostatic fields. Ion spectra show supra-thermal tails resulting from stochastic scattering in the turbulent electric field. Together, these modifications in the plasma flow will affect the properties of the shock and particle acceleration there.
KW  - acceleration of particles
KW  - shock waves
KW  - turbulence
KW  - methods: numerical
KW  - cosmic rays
KW  - ISM: supernova remnants
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx1201
SN  - 0035-8711
SN  - 1365-2966
VL  - 469
SP  - 4985
EP  - 4998
PB  - Oxford Univ. Press
CY  - Oxford
ER  -