@techreport{2021arXiv210813442H,
	title = {Measuring the {HI} content of individual galaxies out to the epoch of reionization with [{CII}]},
	url = {https://ui.adsabs.harvard.edu/abs/2021arXiv210813442H},
	abstract = {The HI gas content is a key ingredient in galaxy evolution, the study of which has been limited to moderate cosmological distances for individual galaxies due to the weakness of the hyperfine HI 21-cm transition. Here we present a new approach that allows us to infer the HI gas mass \$M\_\{{\textbackslash}rm HI\}\$ of individual galaxies up to \$z{\textbackslash}approx 6\$, based on a direct measurement of the [CII]-to-HI conversion factor in star-forming galaxies at \$zrsim 2\$ using \${\textbackslash}gamma\$-ray burst afterglows. By compiling recent [CII]-158 \${\textbackslash}mu\$m emission line measurements we quantify the evolution of the HI content in galaxies through cosmic time. We find that the HI mass starts to exceed the stellar mass \$M\_{\textbackslash}star\$ at \$zrsim 1\$, and increases as a function of redshift. The HI fraction of the total baryonic mass increases from around \$20{\textbackslash}\%\$ at \$z = 0\$ to about \$60{\textbackslash}\%\$ at \$z{\textbackslash}sim 6\$. We further uncover a universal relation between the HI gas fraction \$M\_\{{\textbackslash}rm HI\}/M\_{\textbackslash}star\$ and the gas-phase metallicity, which seems to hold from \$z{\textbackslash}approx 6\$ to \$z=0\$. The majority of galaxies at \$z{\textgreater}2\$ are observed to have HI depletion times, \$t\_\{{\textbackslash}rm dep,HI\} = M\_\{{\textbackslash}rm HI\}/\{{\textbackslash}rm SFR\}\$, less than \${\textbackslash}approx 2\$ Gyr, substantially shorter than for \$z{\textbackslash}sim 0\$ galaxies. Finally, we use the [CII]-to-HI conversion factor to determine the cosmic mass density of HI in galaxies, \${\textbackslash}rho\_\{{\textbackslash}rm HI\}\$, at three distinct epochs: \$z{\textbackslash}approx 0\$, \$z{\textbackslash}approx 2\$, and \$z{\textbackslash}sim 4-6\$. These measurements are consistent with previous estimates based on 21-cm HI observations in the local Universe and with damped Lyman-\${\textbackslash}alpha\$ absorbers (DLAs) at \$zrsim 2\$, suggesting an overall decrease by a factor of \${\textbackslash}approx 5\$ in \${\textbackslash}rho\_\{{\textbackslash}rm HI\}(z)\$ from the end of the reionization epoch to the present.},
	urldate = {2021-09-07},
	author = {Heintz, Kasper E. and Watson, Darach and Oesch, Pascal and Narayanan, Desika and Madden, Suzanne C.},
	month = aug,
	year = {2021},
	note = {Publication Title: arXiv e-prints
ADS Bibcode: 2021arXiv210813442H
Type: article},
	keywords = {Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena},
}

{"_id":"4fX3xinwhza9BtGF6","bibbaseid":"heintz-watson-oesch-narayanan-madden-measuringthehicontentofindividualgalaxiesouttotheepochofreionizationwithcii-2021","author_short":["Heintz, K. E.","Watson, D.","Oesch, P.","Narayanan, D.","Madden, S. C."],"bibdata":{"bibtype":"techreport","type":"techreport","title":"Measuring the HI content of individual galaxies out to the epoch of reionization with [CII]","url":"https://ui.adsabs.harvard.edu/abs/2021arXiv210813442H","abstract":"The HI gas content is a key ingredient in galaxy evolution, the study of which has been limited to moderate cosmological distances for individual galaxies due to the weakness of the hyperfine HI 21-cm transition. Here we present a new approach that allows us to infer the HI gas mass \\$M_\\{{\\textbackslash}rm HI\\}\\$ of individual galaxies up to \\$z{\\textbackslash}approx 6\\$, based on a direct measurement of the [CII]-to-HI conversion factor in star-forming galaxies at \\$zrsim 2\\$ using \\${\\textbackslash}gamma\\$-ray burst afterglows. By compiling recent [CII]-158 \\${\\textbackslash}mu\\$m emission line measurements we quantify the evolution of the HI content in galaxies through cosmic time. We find that the HI mass starts to exceed the stellar mass \\$M_{\\textbackslash}star\\$ at \\$zrsim 1\\$, and increases as a function of redshift. The HI fraction of the total baryonic mass increases from around \\$20{\\textbackslash}%\\$ at \\$z = 0\\$ to about \\$60{\\textbackslash}%\\$ at \\$z{\\textbackslash}sim 6\\$. We further uncover a universal relation between the HI gas fraction \\$M_\\{{\\textbackslash}rm HI\\}/M_{\\textbackslash}star\\$ and the gas-phase metallicity, which seems to hold from \\$z{\\textbackslash}approx 6\\$ to \\$z=0\\$. The majority of galaxies at \\$z{\\textgreater}2\\$ are observed to have HI depletion times, \\$t_\\{{\\textbackslash}rm dep,HI\\} = M_\\{{\\textbackslash}rm HI\\}/\\{{\\textbackslash}rm SFR\\}\\$, less than \\${\\textbackslash}approx 2\\$ Gyr, substantially shorter than for \\$z{\\textbackslash}sim 0\\$ galaxies. Finally, we use the [CII]-to-HI conversion factor to determine the cosmic mass density of HI in galaxies, \\${\\textbackslash}rho_\\{{\\textbackslash}rm HI\\}\\$, at three distinct epochs: \\$z{\\textbackslash}approx 0\\$, \\$z{\\textbackslash}approx 2\\$, and \\$z{\\textbackslash}sim 4-6\\$. These measurements are consistent with previous estimates based on 21-cm HI observations in the local Universe and with damped Lyman-\\${\\textbackslash}alpha\\$ absorbers (DLAs) at \\$zrsim 2\\$, suggesting an overall decrease by a factor of \\${\\textbackslash}approx 5\\$ in \\${\\textbackslash}rho_\\{{\\textbackslash}rm HI\\}(z)\\$ from the end of the reionization epoch to the present.","urldate":"2021-09-07","author":[{"propositions":[],"lastnames":["Heintz"],"firstnames":["Kasper","E."],"suffixes":[]},{"propositions":[],"lastnames":["Watson"],"firstnames":["Darach"],"suffixes":[]},{"propositions":[],"lastnames":["Oesch"],"firstnames":["Pascal"],"suffixes":[]},{"propositions":[],"lastnames":["Narayanan"],"firstnames":["Desika"],"suffixes":[]},{"propositions":[],"lastnames":["Madden"],"firstnames":["Suzanne","C."],"suffixes":[]}],"month":"August","year":"2021","note":"Publication Title: arXiv e-prints ADS Bibcode: 2021arXiv210813442H Type: article","keywords":"Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena","bibtex":"@techreport{2021arXiv210813442H,\n\ttitle = {Measuring the {HI} content of individual galaxies out to the epoch of reionization with [{CII}]},\n\turl = {https://ui.adsabs.harvard.edu/abs/2021arXiv210813442H},\n\tabstract = {The HI gas content is a key ingredient in galaxy evolution, the study of which has been limited to moderate cosmological distances for individual galaxies due to the weakness of the hyperfine HI 21-cm transition. Here we present a new approach that allows us to infer the HI gas mass \\$M\\_\\{{\\textbackslash}rm HI\\}\\$ of individual galaxies up to \\$z{\\textbackslash}approx 6\\$, based on a direct measurement of the [CII]-to-HI conversion factor in star-forming galaxies at \\$zrsim 2\\$ using \\${\\textbackslash}gamma\\$-ray burst afterglows. By compiling recent [CII]-158 \\${\\textbackslash}mu\\$m emission line measurements we quantify the evolution of the HI content in galaxies through cosmic time. We find that the HI mass starts to exceed the stellar mass \\$M\\_{\\textbackslash}star\\$ at \\$zrsim 1\\$, and increases as a function of redshift. The HI fraction of the total baryonic mass increases from around \\$20{\\textbackslash}\\%\\$ at \\$z = 0\\$ to about \\$60{\\textbackslash}\\%\\$ at \\$z{\\textbackslash}sim 6\\$. We further uncover a universal relation between the HI gas fraction \\$M\\_\\{{\\textbackslash}rm HI\\}/M\\_{\\textbackslash}star\\$ and the gas-phase metallicity, which seems to hold from \\$z{\\textbackslash}approx 6\\$ to \\$z=0\\$. The majority of galaxies at \\$z{\\textgreater}2\\$ are observed to have HI depletion times, \\$t\\_\\{{\\textbackslash}rm dep,HI\\} = M\\_\\{{\\textbackslash}rm HI\\}/\\{{\\textbackslash}rm SFR\\}\\$, less than \\${\\textbackslash}approx 2\\$ Gyr, substantially shorter than for \\$z{\\textbackslash}sim 0\\$ galaxies. Finally, we use the [CII]-to-HI conversion factor to determine the cosmic mass density of HI in galaxies, \\${\\textbackslash}rho\\_\\{{\\textbackslash}rm HI\\}\\$, at three distinct epochs: \\$z{\\textbackslash}approx 0\\$, \\$z{\\textbackslash}approx 2\\$, and \\$z{\\textbackslash}sim 4-6\\$. These measurements are consistent with previous estimates based on 21-cm HI observations in the local Universe and with damped Lyman-\\${\\textbackslash}alpha\\$ absorbers (DLAs) at \\$zrsim 2\\$, suggesting an overall decrease by a factor of \\${\\textbackslash}approx 5\\$ in \\${\\textbackslash}rho\\_\\{{\\textbackslash}rm HI\\}(z)\\$ from the end of the reionization epoch to the present.},\n\turldate = {2021-09-07},\n\tauthor = {Heintz, Kasper E. and Watson, Darach and Oesch, Pascal and Narayanan, Desika and Madden, Suzanne C.},\n\tmonth = aug,\n\tyear = {2021},\n\tnote = {Publication Title: arXiv e-prints\nADS Bibcode: 2021arXiv210813442H\nType: article},\n\tkeywords = {Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena},\n}\n\n","author_short":["Heintz, K. E.","Watson, D.","Oesch, P.","Narayanan, D.","Madden, S. C."],"key":"2021arXiv210813442H","id":"2021arXiv210813442H","bibbaseid":"heintz-watson-oesch-narayanan-madden-measuringthehicontentofindividualgalaxiesouttotheepochofreionizationwithcii-2021","role":"author","urls":{"Paper":"https://ui.adsabs.harvard.edu/abs/2021arXiv210813442H"},"keyword":["Astrophysics - Astrophysics of Galaxies","Astrophysics - High Energy Astrophysical Phenomena"],"metadata":{"authorlinks":{}}},"bibtype":"techreport","biburl":"https://bibbase.org/zotero/polyphant","dataSources":["7gvjSdWrEu7z5vjjj"],"keywords":["astrophysics - astrophysics of galaxies","astrophysics - high energy astrophysical phenomena"],"search_terms":["measuring","content","individual","galaxies","out","epoch","reionization","cii","heintz","watson","oesch","narayanan","madden"],"title":"Measuring the HI content of individual galaxies out to the epoch of reionization with [CII]","year":2021}