%0 Generic %1 finlator2013halos %A Finlator, K. %A Muñoz, J. A. %A Oppenheimer, B. D. %A Oh, S. Peng %A Özel, F. %A Davé, R. %D 2013 %K absorbers halos host reionization %T The Host Halos of OI Absorbers in the Reionization Epoch %U http://arxiv.org/abs/1305.4768 %X We use a radiation hydrodynamic simulation that models the growth of galaxies and the extragalactic ultraviolet ionizing background (EUVB) self-consistently to study the sources of OI absorption during the hydrogen reionization epoch. Diffuse regions in the intergalactic medium (IGM) are reionized before they are enriched, hence OI absorption is closely associated with dark matter haloes. At z=10, all haloes above the hydrogen cooling limit produce visible absorption out to a substantial fraction of the virial radius. As reionization proceeds, the nascent EUVB ionizes and removes gas from low-mass haloes, leading to a cutoff mass below which the geometric cross section for producing observable absorption vanishes. The cutoff grows from 10^7.9 M_0 at z=10 to 10^8.4 M_0 at z=5. This is 10-100 times less massive than the host haloes of Lyman break galaxies and Lyman-alpha emitters, suggesting that OI absorption probes the mass scale of ionizing sources that drove reionization more directly. OI absorbers are predicted to have neutral hydrogen columns of 10^19-10^21 cm^-2 suggesting a close resemblance between objects selected in OI and HI. The predicted abundance of OI absorbers at z=6 is in reasonable agreement with observations although in detail it may be slightly low, consistent with evidence from the Lyman-alpha forest that the predicted EUVB is slightly too strong. We also consider the upper limits on the OI column density of the absorber in the foreground of the z=7.085 quasar ULASJ1120+0641 and find that they cannot be satisfied by halo gas because gas at the observed HI column density enriches too quickly. By contrast, gas at less than one third the mean density readily satisfies the constraints at z>=7. Hence the foreground absorption in ULASJ1120+0641 likely originates in the diffuse IGM rather than in a discrete system.

@misc{finlator2013halos, abstract = {We use a radiation hydrodynamic simulation that models the growth of galaxies and the extragalactic ultraviolet ionizing background (EUVB) self-consistently to study the sources of OI absorption during the hydrogen reionization epoch. Diffuse regions in the intergalactic medium (IGM) are reionized before they are enriched, hence OI absorption is closely associated with dark matter haloes. At z=10, all haloes above the hydrogen cooling limit produce visible absorption out to a substantial fraction of the virial radius. As reionization proceeds, the nascent EUVB ionizes and removes gas from low-mass haloes, leading to a cutoff mass below which the geometric cross section for producing observable absorption vanishes. The cutoff grows from 10^7.9 M_0 at z=10 to 10^8.4 M_0 at z=5. This is 10-100 times less massive than the host haloes of Lyman break galaxies and Lyman-alpha emitters, suggesting that OI absorption probes the mass scale of ionizing sources that drove reionization more directly. OI absorbers are predicted to have neutral hydrogen columns of 10^19-10^21 cm^-2 suggesting a close resemblance between objects selected in OI and HI. The predicted abundance of OI absorbers at z=6 is in reasonable agreement with observations although in detail it may be slightly low, consistent with evidence from the Lyman-alpha forest that the predicted EUVB is slightly too strong. We also consider the upper limits on the OI column density of the absorber in the foreground of the z=7.085 quasar ULASJ1120+0641 and find that they cannot be satisfied by halo gas because gas at the observed HI column density enriches too quickly. By contrast, gas at less than one third the mean density readily satisfies the constraints at z>=7. Hence the foreground absorption in ULASJ1120+0641 likely originates in the diffuse IGM rather than in a discrete system.}, added-at = {2013-05-22T19:21:52.000+0200}, author = {Finlator, K. and Muñoz, J. A. and Oppenheimer, B. D. and Oh, S. Peng and Özel, F. and Davé, R.}, biburl = {https://www.bibsonomy.org/bibtex/212d55b37ccb7e3ef38aae69d6ae27191/miki}, description = {[1305.4768] The Host Halos of OI Absorbers in the Reionization Epoch}, interhash = {f26b8d350395c1ceda0283af140906d2}, intrahash = {12d55b37ccb7e3ef38aae69d6ae27191}, keywords = {absorbers halos host reionization}, note = {cite arxiv:1305.4768Comment: 19 pages, 15 figures, submitted to MNRAS}, timestamp = {2013-05-22T19:21:52.000+0200}, title = {The Host Halos of OI Absorbers in the Reionization Epoch}, url = {http://arxiv.org/abs/1305.4768}, year = 2013 }