The Neutral Hydrogen Cosmological Mass Density at z = 5

By N. Crighton, M. Murphy, J. Xavier Prochaska, G. Worseck, M. Rafelski, George D. Becker, Sara L. Ellison, Michele Fumagalli, S. López, A. Meiksin and 1 more. Proceedings of the International Astronomical Union, 2015

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Abstract We present the largest homogeneous survey of redshift > 4.4 damped Lyα systems (DLAs) using the spectra of 163 quasars that comprise the Giant Gemini GMOS (GGG) survey. With this survey we make the most precise high-redshift measurement of the cosmological mass density of neutral hydrogen, ΩHI. After correcting for systematic effects using a combination of mock and higher-resolution spectra, we find ΩHI= 0.98+0.20 -0.18 × 10−3 at 〈z〉 = 4.9, assuming a 20% contribution from lower column density systems below the DLA threshold. By comparing to literature measurements at lower redshifts, we show that ΩHI can be described by the functional form ΩHI(z) ∝ (1 + z)0.4. This gradual decrease from z = 5 to 0 suggests that in the galaxies which dominate the cosmic star formation rate, Hi is a transitory gas phase fuelling star formation which must be continually replenished by more highly-ionized gas from the intergalactic medium, and from recycled galactic winds.

Subfields: Astronomy and Astrophysics, Instrumentation

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Citations in the corpus

Ingredients for 21 cm Intensity Mapping (2018, methodology): “We find excellent agreement with the observations, which are shown as black points with errorbars, at redshifts [1.8-3.5] (Péroux et al. 2005), [2.0-3.5] (Noterdaeme et al. 2012), [3.5- 5.4] (Crighton et al. 2015) and [1.5-5.0] (Zafar et al. 2013).”
An Overview of CHIME, the Canadian Hydrogen Intensity Mapping Experiment (2022, methodology): “For Tb(z), we use the expression from Hall et al. (2013), with the fitting formula for the mean HI density ΩHI(z) from Crighton et al. (2015), and for bHI(z), we use the model from Cosmic Visions 21 cm Collaboration et al. (2018), that smoothly interpolates between measurements from the…”