@article{balashev_co-dark_2017,
	title = {{CO}-dark molecular gas at high redshift: very large {H}\$\_2\$ content and high pressure in a low metallicity damped {Lyman}-alpha system},
	shorttitle = {{CO}-dark molecular gas at high redshift},
	url = {http://arxiv.org/abs/1705.10283},
	abstract = {We present a detailed analysis of a H\$\_2\$-rich, extremely strong intervening Damped Ly-\${\textbackslash}alpha\$ Absorption system (DLA) at \$z\_\{{\textbackslash}rm abs\}=2.786\$ towards the quasar J\${\textbackslash},\$0843+0221, observed with the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. The total column density of molecular (resp. atomic) hydrogen is \${\textbackslash}log N\$(H\$\_2\$)=\$21.21{\textbackslash}pm0.02\$ (resp. \${\textbackslash}log N\$(H\${\textbackslash},\$I)=\$21.82{\textbackslash}pm0.11\$), making it to be the first case in quasar absorption lines studies with H\$\_2\$ column density as high as what is seen in \${\textasciicircum}\{13\}\$CO-selected clouds in the Milky-Way. We find that this system has one of the lowest metallicity detected among H\$\_2\$-bearing DLAs, with \${\textbackslash}rm [Zn/H]=-1.52{\textasciicircum}\{+0.08\}\_\{-0.10\}\$. This can be the reason for the marked differences compared to systems with similar H\$\_2\$ column densities in the local Universe: \$(i)\$ the kinetic temperature, \$T{\textbackslash}sim\$120{\textasciitilde}K, derived from the \$J=0,1\$ H\$\_2\$ rotational levels is at least twice higher than expected; \$(ii)\$ there is little dust extinction with A\$\_V {\textless} 0.1\$; \$(iii)\$ no CO molecules are detected, putting a constraint on the \$X\_\{{\textbackslash}rm CO\}\$ factor \$X\_\{{\textbackslash}rm CO\}{\textgreater} 2{\textbackslash}times 10{\textasciicircum}\{23\} \$ cm\${\textasciicircum}\{-2\}\$/(km/s{\textbackslash},K), in the very low metallicity gas. Low CO and high H\$\_2\$ contents indicate that this system represents "CO-dark/faint" gas. We investigate the physical conditions in the H\$\_2\$-bearing gas using the fine-structure levels of C\${\textbackslash},\$I, C\${\textbackslash},\$II, Si\${\textbackslash},\$II and the rotational levels of HD and H\$\_2\$. We find the number density to be about \$n {\textbackslash}sim 260-380{\textbackslash},\$cm\${\textasciicircum}\{-3\}\$, implying a high thermal pressure of \$(3-5) {\textbackslash}times 10{\textasciicircum}4{\textbackslash},\$cm\${\textasciicircum}\{-3\}{\textbackslash},\$K. We further identify a trend of increasing pressure with increasing total hydrogen column density. This independently supports the suggestion that extremely strong DLAs (with \${\textbackslash}log{\textbackslash},\$N(H) \${\textbackslash}sim 22\$) probe high-z galaxies at low impact parameters.},
	journal = {arXiv:1705.10283 [astro-ph]},
	author = {Balashev, S. A. and Noterdaeme, P. and Rahmani, H. and Klimenko, V. V. and Ledoux, C. and Petitjean, P. and Srianand, R. and Ivanchik, A. V. and Varshalovich, D. A.},
	month = may,
	year = {2017},
	note = {arXiv: 1705.10283},
	keywords = {Astrophysics - Astrophysics of Galaxies},
}

{"_id":"EjwrueYNZrLiFGkR4","bibbaseid":"balashev-noterdaeme-rahmani-klimenko-ledoux-petitjean-srianand-ivanchik-etal-codarkmoleculargasathighredshiftverylargeh2contentandhighpressureinalowmetallicitydampedlymanalphasystem-2017","author_short":["Balashev, S. A.","Noterdaeme, P.","Rahmani, H.","Klimenko, V. V.","Ledoux, C.","Petitjean, P.","Srianand, R.","Ivanchik, A. V.","Varshalovich, D. A."],"bibdata":{"bibtype":"article","type":"article","title":"CO-dark molecular gas at high redshift: very large H\\$_2\\$ content and high pressure in a low metallicity damped Lyman-alpha system","shorttitle":"CO-dark molecular gas at high redshift","url":"http://arxiv.org/abs/1705.10283","abstract":"We present a detailed analysis of a H\\$_2\\$-rich, extremely strong intervening Damped Ly-\\${\\textbackslash}alpha\\$ Absorption system (DLA) at \\$z_\\{{\\textbackslash}rm abs\\}=2.786\\$ towards the quasar J\\${\\textbackslash},\\$0843+0221, observed with the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. The total column density of molecular (resp. atomic) hydrogen is \\${\\textbackslash}log N\\$(H\\$_2\\$)=\\$21.21{\\textbackslash}pm0.02\\$ (resp. \\${\\textbackslash}log N\\$(H\\${\\textbackslash},\\$I)=\\$21.82{\\textbackslash}pm0.11\\$), making it to be the first case in quasar absorption lines studies with H\\$_2\\$ column density as high as what is seen in \\${\\textasciicircum}\\{13\\}\\$CO-selected clouds in the Milky-Way. We find that this system has one of the lowest metallicity detected among H\\$_2\\$-bearing DLAs, with \\${\\textbackslash}rm [Zn/H]=-1.52{\\textasciicircum}\\{+0.08\\}_\\{-0.10\\}\\$. This can be the reason for the marked differences compared to systems with similar H\\$_2\\$ column densities in the local Universe: \\$(i)\\$ the kinetic temperature, \\$T{\\textbackslash}sim\\$120\\textasciitildeK, derived from the \\$J=0,1\\$ H\\$_2\\$ rotational levels is at least twice higher than expected; \\$(ii)\\$ there is little dust extinction with A\\$_V {\\textless} 0.1\\$; \\$(iii)\\$ no CO molecules are detected, putting a constraint on the \\$X_\\{{\\textbackslash}rm CO\\}\\$ factor \\$X_\\{{\\textbackslash}rm CO\\}{\\textgreater} 2{\\textbackslash}times 10{\\textasciicircum}\\{23\\} \\$ cm\\${\\textasciicircum}\\{-2\\}\\$/(km/s\\textbackslash,K), in the very low metallicity gas. Low CO and high H\\$_2\\$ contents indicate that this system represents \"CO-dark/faint\" gas. We investigate the physical conditions in the H\\$_2\\$-bearing gas using the fine-structure levels of C\\${\\textbackslash},\\$I, C\\${\\textbackslash},\\$II, Si\\${\\textbackslash},\\$II and the rotational levels of HD and H\\$_2\\$. We find the number density to be about \\$n {\\textbackslash}sim 260-380{\\textbackslash},\\$cm\\${\\textasciicircum}\\{-3\\}\\$, implying a high thermal pressure of \\$(3-5) {\\textbackslash}times 10{\\textasciicircum}4{\\textbackslash},\\$cm\\${\\textasciicircum}\\{-3\\}{\\textbackslash},\\$K. We further identify a trend of increasing pressure with increasing total hydrogen column density. This independently supports the suggestion that extremely strong DLAs (with \\${\\textbackslash}log{\\textbackslash},\\$N(H) \\${\\textbackslash}sim 22\\$) probe high-z galaxies at low impact parameters.","journal":"arXiv:1705.10283 [astro-ph]","author":[{"propositions":[],"lastnames":["Balashev"],"firstnames":["S.","A."],"suffixes":[]},{"propositions":[],"lastnames":["Noterdaeme"],"firstnames":["P."],"suffixes":[]},{"propositions":[],"lastnames":["Rahmani"],"firstnames":["H."],"suffixes":[]},{"propositions":[],"lastnames":["Klimenko"],"firstnames":["V.","V."],"suffixes":[]},{"propositions":[],"lastnames":["Ledoux"],"firstnames":["C."],"suffixes":[]},{"propositions":[],"lastnames":["Petitjean"],"firstnames":["P."],"suffixes":[]},{"propositions":[],"lastnames":["Srianand"],"firstnames":["R."],"suffixes":[]},{"propositions":[],"lastnames":["Ivanchik"],"firstnames":["A.","V."],"suffixes":[]},{"propositions":[],"lastnames":["Varshalovich"],"firstnames":["D.","A."],"suffixes":[]}],"month":"May","year":"2017","note":"arXiv: 1705.10283","keywords":"Astrophysics - Astrophysics of Galaxies","bibtex":"@article{balashev_co-dark_2017,\n\ttitle = {{CO}-dark molecular gas at high redshift: very large {H}\\$\\_2\\$ content and high pressure in a low metallicity damped {Lyman}-alpha system},\n\tshorttitle = {{CO}-dark molecular gas at high redshift},\n\turl = {http://arxiv.org/abs/1705.10283},\n\tabstract = {We present a detailed analysis of a H\\$\\_2\\$-rich, extremely strong intervening Damped Ly-\\${\\textbackslash}alpha\\$ Absorption system (DLA) at \\$z\\_\\{{\\textbackslash}rm abs\\}=2.786\\$ towards the quasar J\\${\\textbackslash},\\$0843+0221, observed with the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. The total column density of molecular (resp. atomic) hydrogen is \\${\\textbackslash}log N\\$(H\\$\\_2\\$)=\\$21.21{\\textbackslash}pm0.02\\$ (resp. \\${\\textbackslash}log N\\$(H\\${\\textbackslash},\\$I)=\\$21.82{\\textbackslash}pm0.11\\$), making it to be the first case in quasar absorption lines studies with H\\$\\_2\\$ column density as high as what is seen in \\${\\textasciicircum}\\{13\\}\\$CO-selected clouds in the Milky-Way. We find that this system has one of the lowest metallicity detected among H\\$\\_2\\$-bearing DLAs, with \\${\\textbackslash}rm [Zn/H]=-1.52{\\textasciicircum}\\{+0.08\\}\\_\\{-0.10\\}\\$. This can be the reason for the marked differences compared to systems with similar H\\$\\_2\\$ column densities in the local Universe: \\$(i)\\$ the kinetic temperature, \\$T{\\textbackslash}sim\\$120{\\textasciitilde}K, derived from the \\$J=0,1\\$ H\\$\\_2\\$ rotational levels is at least twice higher than expected; \\$(ii)\\$ there is little dust extinction with A\\$\\_V {\\textless} 0.1\\$; \\$(iii)\\$ no CO molecules are detected, putting a constraint on the \\$X\\_\\{{\\textbackslash}rm CO\\}\\$ factor \\$X\\_\\{{\\textbackslash}rm CO\\}{\\textgreater} 2{\\textbackslash}times 10{\\textasciicircum}\\{23\\} \\$ cm\\${\\textasciicircum}\\{-2\\}\\$/(km/s{\\textbackslash},K), in the very low metallicity gas. Low CO and high H\\$\\_2\\$ contents indicate that this system represents \"CO-dark/faint\" gas. We investigate the physical conditions in the H\\$\\_2\\$-bearing gas using the fine-structure levels of C\\${\\textbackslash},\\$I, C\\${\\textbackslash},\\$II, Si\\${\\textbackslash},\\$II and the rotational levels of HD and H\\$\\_2\\$. We find the number density to be about \\$n {\\textbackslash}sim 260-380{\\textbackslash},\\$cm\\${\\textasciicircum}\\{-3\\}\\$, implying a high thermal pressure of \\$(3-5) {\\textbackslash}times 10{\\textasciicircum}4{\\textbackslash},\\$cm\\${\\textasciicircum}\\{-3\\}{\\textbackslash},\\$K. We further identify a trend of increasing pressure with increasing total hydrogen column density. This independently supports the suggestion that extremely strong DLAs (with \\${\\textbackslash}log{\\textbackslash},\\$N(H) \\${\\textbackslash}sim 22\\$) probe high-z galaxies at low impact parameters.},\n\tjournal = {arXiv:1705.10283 [astro-ph]},\n\tauthor = {Balashev, S. A. and Noterdaeme, P. and Rahmani, H. and Klimenko, V. V. and Ledoux, C. and Petitjean, P. and Srianand, R. and Ivanchik, A. V. and Varshalovich, D. A.},\n\tmonth = may,\n\tyear = {2017},\n\tnote = {arXiv: 1705.10283},\n\tkeywords = {Astrophysics - Astrophysics of Galaxies},\n}\n\n","author_short":["Balashev, S. A.","Noterdaeme, P.","Rahmani, H.","Klimenko, V. V.","Ledoux, C.","Petitjean, P.","Srianand, R.","Ivanchik, A. V.","Varshalovich, D. A."],"key":"balashev_co-dark_2017","id":"balashev_co-dark_2017","bibbaseid":"balashev-noterdaeme-rahmani-klimenko-ledoux-petitjean-srianand-ivanchik-etal-codarkmoleculargasathighredshiftverylargeh2contentandhighpressureinalowmetallicitydampedlymanalphasystem-2017","role":"author","urls":{"Paper":"http://arxiv.org/abs/1705.10283"},"keyword":["Astrophysics - Astrophysics of Galaxies"],"metadata":{"authorlinks":{}}},"bibtype":"article","biburl":"https://bibbase.org/zotero/polyphant","dataSources":["7gvjSdWrEu7z5vjjj"],"keywords":["astrophysics - astrophysics of galaxies"],"search_terms":["dark","molecular","gas","high","redshift","very","large","content","high","pressure","low","metallicity","damped","lyman","alpha","system","balashev","noterdaeme","rahmani","klimenko","ledoux","petitjean","srianand","ivanchik","varshalovich"],"title":"CO-dark molecular gas at high redshift: very large H\\$_2\\$ content and high pressure in a low metallicity damped Lyman-alpha system","year":2017}