TY - JOUR A1 - Petruk, Oleh A1 - Kuzyo, T. A1 - Orlando, S. A1 - Pohl, Martin A1 - Miceli, M. A1 - Bocchino, F. A1 - Beshley, V. A1 - Brose, Robert T1 - Post-adiabatic supernova remnants in an interstellar magnetic field BT - oblique shocks and non-uniform environment JF - Monthly notices of the Royal Astronomical Society N2 - We present very-high-resolution 1D MHD simulations of the late-stage supernova remnants (SNRs). In the post-adiabatic stage, the magnetic field has an important and significant dynamical effect on the shock dynamics, the flow structure, and hence the acceleration and emission of cosmic rays. We find that the tangential component of the magnetic field provides pressure support that to a fair degree prevents the collapse of the radiative shell and thus limits the total compression ratio of the partially or fully radiative forward shock. A consequence is that the spectra of cosmic rays would not be as hard as in hydrodynamic simulations. We also investigated the effect on the flow profiles of the magnetic-field inclination and a large-scale gradient in the gas density and/or the magnetic field. A positive density gradient shortens the evolutionary stages, whereas a shock obliquity lowers the shock compression. The compression of the tangential component of the magnetic field leads to its dominance in the downstream region of post-adiabatic shocks for a wide range of orientation of the upstream field, which may explain why one preferentially observes tangential radio polarization in old SNRs. As most cosmic rays are produced at late stages of SNR evolution, the post-adiabatic phase and the influence of the magnetic field during it are most important for modeling the cosmic-ray acceleration at old SNRs and the gamma-ray emission from late-stage SNRs interacting with clouds. KW - shock waves KW - ISM: magnetic fields KW - ISM: supernova remnants Y1 - 2018 U6 - https://doi.org/10.1093/mnras/sty1750 SN - 0035-8711 SN - 1365-2966 VL - 479 IS - 3 SP - 4253 EP - 4270 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Sushch, Iurii A1 - Brose, Robert A1 - Pohl, Martin T1 - Modeling of the spatially resolved nonthermal emission from the Vela Jr. supernova remnant JF - Astronomy and astrophysics : an international weekly journal N2 - Vela Jr. (RX J0852.0-4622) is one of just a few known supernova remnants (SNRs) with a resolved shell across the whole electromagnetic spectrum from radio to very-high-energy (>100 GeV; VHE) gamma-rays. Its proximity and large size allow for detailed spatially resolved observations of the source, making Vela Jr. one of the primary sources used for the study of particle acceleration and emission mechanisms in SNRs. High-resolution X-ray observations reveal a steepening of the spectrum toward the interior of the remnant. In this study we aim for a self-consistent radiation model of Vela Jr. which at the same time would explain the broadband emission from the source and its intensity distribution. We solve the full particle transport equation combined with the high-resolution one-dimensional (1D) hydrodynamic simulations (using Pluto code) and subsequently calculate the radiation from the remnant. The equations are solved in the test particle regime. We test two models for the magnetic field profile downstream of the shock: damped magnetic field, which accounts for the damping of strong magnetic turbulence downstream, and transported magnetic field. Neither of these scenarios can fully explain the observed radial dependence of the X-ray spectrum under spherical symmetry. We show, however, that the softening of the spectrum and the X-ray intensity profile can be explained under the assumption that the emission is enhanced within a cone. KW - radiation mechanisms: non-thermal KW - acceleration of particles KW - cosmic rays KW - ISM: supernova remnants KW - X-rays: individuals: Vela Jr (RX J08520-4622) KW - shock waves Y1 - 2018 U6 - https://doi.org/10.1051/0004-6361/201832879 SN - 1432-0746 SN - 0004-6361 VL - 618 PB - EDP Sciences CY - Les Ulis ER -