The evolution of neutral gas in damped Lyman α systems from the XQ-100 survey

TY - JOUR

T1 - The evolution of neutral gas in damped Lyman α systems from the XQ-100 survey

AU - Sánchez-Ramírez, R.

AU - Ellison, S. L.

AU - Prochaska, J. X.

AU - Berg, T. A. M.

AU - López, S.

AU - D'Odorico, V.

AU - Becker, G. D.

AU - Christensen, Lise Bech

AU - Cupani, G.

AU - Denney, K. D.

AU - Pâris, I.

AU - Worseck, G.

AU - Gorosabel, J.

N1 - Submitted to MNRAS, this version follows the referee's report and minor revisions. Large tables are included in the source file tarball

PY - 2016/3/11

Y1 - 2016/3/11

N2 - We present a sample of 38 intervening damped Lyman α (DLA) systems identified towards 100 z > 3.5 quasars, observed during the XQ-100 survey. The XQ-100 DLA sample is combined with majorDLAsurveys in the literature. The final combined sample consists of 742 DLAs over a redshift range approximately 1.6 < zabs < 5.0. We develop a novel technique for computing ΩHI DLA as a continuous function of redshift, and we thoroughly assess and quantify the sources of error therein, including fitting errors and incomplete sampling of the high column density end of the column density distribution function. There is a statistically significant redshift evolution in ΩHI DLA (≥ 3σ) fromz ~ 2 to z ~ 5. In order to make a complete assessment of the redshift evolution of ΩHI, we combine our high-redshift DLA sample with absorption surveys at intermediate redshift and 21-cm emission line surveys of the local universe. Although ΩHI DLA, and hence its redshift evolution, remains uncertain in the intermediate-redshift regime (0.1 < zabs < 1.6), we find that the combination of high-redshift data with 21-cm surveys of the local universe all yield a statistically significant evolution in ΩHI from z ~ 0 to z ~ 5 (≥ 3σ). Despite its statistical significance, the magnitude of the evolution is small: A linear regression fit between ΩHI and z yields a typical slope of ~0.17 × 10-3, corresponding to a factor of ~4 decrease in ΩHI between z = 5 and z = 0.

AB - We present a sample of 38 intervening damped Lyman α (DLA) systems identified towards 100 z > 3.5 quasars, observed during the XQ-100 survey. The XQ-100 DLA sample is combined with majorDLAsurveys in the literature. The final combined sample consists of 742 DLAs over a redshift range approximately 1.6 < zabs < 5.0. We develop a novel technique for computing ΩHI DLA as a continuous function of redshift, and we thoroughly assess and quantify the sources of error therein, including fitting errors and incomplete sampling of the high column density end of the column density distribution function. There is a statistically significant redshift evolution in ΩHI DLA (≥ 3σ) fromz ~ 2 to z ~ 5. In order to make a complete assessment of the redshift evolution of ΩHI, we combine our high-redshift DLA sample with absorption surveys at intermediate redshift and 21-cm emission line surveys of the local universe. Although ΩHI DLA, and hence its redshift evolution, remains uncertain in the intermediate-redshift regime (0.1 < zabs < 1.6), we find that the combination of high-redshift data with 21-cm surveys of the local universe all yield a statistically significant evolution in ΩHI from z ~ 0 to z ~ 5 (≥ 3σ). Despite its statistical significance, the magnitude of the evolution is small: A linear regression fit between ΩHI and z yields a typical slope of ~0.17 × 10-3, corresponding to a factor of ~4 decrease in ΩHI between z = 5 and z = 0.

KW - astro-ph.CO

KW - astro-ph.GA

U2 - 10.1093/mnras/stv2732

DO - 10.1093/mnras/stv2732

M3 - Journal article

SN - 0035-8711

VL - 456

SP - 4488

EP - 4505

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

IS - 4

ER -