%0 Generic %1 salem2015cosmic %A Salem, Munier %A Bryan, Greg L. %A Corlies, Lauren %D 2015 %K cgm cosmic rays simulation %T Role of Cosmic Rays in the Circumgalactic Medium %U http://arxiv.org/abs/1511.05144 %X We explore the impact of cosmic rays (CRs) on cosmological adaptive-mesh refinement simulations of a forming 10^12 Msolar halo, focusing on the circumgalactic medium (CGM), and its resulting low-redshift structure and composition. In contrast to a run with star formation and energetic feedback but no CRs, the CR-inclusive runs feature a CGM substantially enriched with CRs and with metals to roughly 0.1 Zsolar, thanks to robust, persistent outflows from the disk. The CR-inclusive CGMs also feature more diffuse gas at lower temperatures, down to 10^4 K, than the non-CR run, with diffuse material often receiving a majority of its pressure support from the CR proton fluid. We compare to recent observations of the CGM of L ~ L* galaxies at low redshift, including UV absorption lines within background quasar spectra. The combination of metal-enriched, CR-driven winds and large swaths of CR pressure-supported, cooler diffuse gas leads to a CGM that provides a better match to data from COS-Halos (for HI, SiIV, CIII and OVI) than the non-CR run. We also compare our models to recent, preliminary observations of diffuse gamma-ray emission in local group halos. For our lower CR-diffusion runs with kappa_CR in the range 0.3 to 1 x 10^28 cm^2/s, the CR enriched CGM produces an inconsistently high level of gamma emission. But the model with a relatively high kappa_CR = 3 x 10^28 cm^2/s provided a gamma-ray luminosity consistent with the extra-galactic gamma-ray background observed by FERMI and roughly consistent with preliminary measures of the emission from M31's CGM.

@misc{salem2015cosmic, abstract = {We explore the impact of cosmic rays (CRs) on cosmological adaptive-mesh refinement simulations of a forming 10^12 Msolar halo, focusing on the circumgalactic medium (CGM), and its resulting low-redshift structure and composition. In contrast to a run with star formation and energetic feedback but no CRs, the CR-inclusive runs feature a CGM substantially enriched with CRs and with metals to roughly 0.1 Zsolar, thanks to robust, persistent outflows from the disk. The CR-inclusive CGMs also feature more diffuse gas at lower temperatures, down to 10^4 K, than the non-CR run, with diffuse material often receiving a majority of its pressure support from the CR proton fluid. We compare to recent observations of the CGM of L ~ L* galaxies at low redshift, including UV absorption lines within background quasar spectra. The combination of metal-enriched, CR-driven winds and large swaths of CR pressure-supported, cooler diffuse gas leads to a CGM that provides a better match to data from COS-Halos (for HI, SiIV, CIII and OVI) than the non-CR run. We also compare our models to recent, preliminary observations of diffuse gamma-ray emission in local group halos. For our lower CR-diffusion runs with kappa_CR in the range 0.3 to 1 x 10^28 cm^2/s, the CR enriched CGM produces an inconsistently high level of gamma emission. But the model with a relatively high kappa_CR = 3 x 10^28 cm^2/s provided a gamma-ray luminosity consistent with the extra-galactic gamma-ray background observed by FERMI and roughly consistent with preliminary measures of the emission from M31's CGM.}, added-at = {2015-11-18T11:01:55.000+0100}, author = {Salem, Munier and Bryan, Greg L. and Corlies, Lauren}, biburl = {https://www.bibsonomy.org/bibtex/200825263d10eb7206926b3d6788e908e/miki}, description = {[1511.05144] Role of Cosmic Rays in the Circumgalactic Medium}, interhash = {ff06f90c1d431a656b56e7eec3900477}, intrahash = {00825263d10eb7206926b3d6788e908e}, keywords = {cgm cosmic rays simulation}, note = {cite arxiv:1511.05144Comment: 22 pages, 14 figures, MNRAS in press}, timestamp = {2015-11-18T11:01:55.000+0100}, title = {Role of Cosmic Rays in the Circumgalactic Medium}, url = {http://arxiv.org/abs/1511.05144}, year = 2015 }