%0 Generic %1 gurvich2016column %A Gurvich, Alex %A Burkhart, Blakesley %A Bird, Simeon %D 2016 %K IGM low redshift simulation uvb %T The Column Density Distribution of the Low-Redshift Lyman-Alpha Forest in Illustris %U http://arxiv.org/abs/1608.03293 %X We investigate the low-redshift Lyman-alpha forest column density distribution in the Illustris simulation. We show that Illustris reproduces observations extremely well in the column density range 10^12.5-10^14.5 cm^-2, relevant for the "photon underproduction crisis." We attribute this to the inclusion of AGN feedback, which changes the gas distribution so as to mimic the effect of extra photons, as well as the use of the Faucher-Giguere (2009) ultra-violet background, which is more ionizing at z=0.1 than the Haardt & Madau (2012) background previously considered. We show that the difference between simulations run with smoothed particle hydrodynamics and simulations using a moving mesh is small in this column density range. We further consider the effect of supernova feedback, Voigt profile fitting and finite resolution, all of which we show to be small. Finally, we identify a discrepancy between our simulations and observations at column densities 10^14-10^16 cm^-2, where Illustris produces too few absorbers, which suggests the AGN feedback model in cosmological simulations should be further refined. However the "photon underproduction crisis," can be resolved by including AGN feedback and standard ionizing background models.

@misc{gurvich2016column, abstract = {We investigate the low-redshift Lyman-alpha forest column density distribution in the Illustris simulation. We show that Illustris reproduces observations extremely well in the column density range 10^12.5-10^14.5 cm^-2, relevant for the "photon underproduction crisis." We attribute this to the inclusion of AGN feedback, which changes the gas distribution so as to mimic the effect of extra photons, as well as the use of the Faucher-Giguere (2009) ultra-violet background, which is more ionizing at z=0.1 than the Haardt & Madau (2012) background previously considered. We show that the difference between simulations run with smoothed particle hydrodynamics and simulations using a moving mesh is small in this column density range. We further consider the effect of supernova feedback, Voigt profile fitting and finite resolution, all of which we show to be small. Finally, we identify a discrepancy between our simulations and observations at column densities 10^14-10^16 cm^-2, where Illustris produces too few absorbers, which suggests the AGN feedback model in cosmological simulations should be further refined. However the "photon underproduction crisis," can be resolved by including AGN feedback and standard ionizing background models.}, added-at = {2016-08-12T10:41:47.000+0200}, author = {Gurvich, Alex and Burkhart, Blakesley and Bird, Simeon}, biburl = {https://www.bibsonomy.org/bibtex/2346082de32dbada3f1d9430c33604853/miki}, description = {[1608.03293] The Column Density Distribution of the Low-Redshift Lyman-Alpha Forest in Illustris}, interhash = {07a07e31c286e245a6eb43bc41dc6959}, intrahash = {346082de32dbada3f1d9430c33604853}, keywords = {IGM low redshift simulation uvb}, note = {cite arxiv:1608.03293}, timestamp = {2016-08-12T10:41:47.000+0200}, title = {The Column Density Distribution of the Low-Redshift Lyman-Alpha Forest in Illustris}, url = {http://arxiv.org/abs/1608.03293}, year = 2016 }