H2+ and primordial chemistry (trac #356)

reported by: @CloudyLex

Title:  
Role of the H_2^+ channel in the primordial star formation under strong radiation field and the critical intensity for the supermassive star formation
Authors:    
Sugimura, K.; Coppola, C. M.; Omukai, K.; Galli, D.; Palla, F.
Affiliation:    
AA(Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan sugimura@astr.tohoku.ac.jp), AB(Dipartimento di Chimica, Università degli Studi di Bari, Via Orabona 4, I-70126 Bari, Italy; INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy), AC(Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan), AD(INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy), AE(INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy)
Publication:    
Monthly Notices of the Royal Astronomical Society, Volume 456, Issue 1, p.270-277 (MNRAS Homepage)
Publication Date:   
02/2016
Origin: 
OUP
Astronomy Keywords: 
molecular processes, quasars: supermassive black holes, cosmology: theory
Abstract Copyright: 
2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
DOI:    
10.1093/mnras/stv2655
Bibliographic Code: 
2016MNRAS.456..270S
Abstract

We investigate the role of the H_2^+ channel on H2 molecule formation 
during the collapse of primordial gas clouds immersed in strong radiation 
fields which are assumed to have the shape of a diluted blackbody spectra 
with temperature Trad. Since the photodissociation rate of H_2^+ depends 
on its level population, we take full account of the vibrationally resolved 
H_2^+ kinetics. We find that in clouds under soft but intense radiation fields 
with spectral temperature Trad ? 7000 K, the H_2^+ channel is the 
dominant H2 formation process. On the other hand, for harder spectra with 
Trad ? 7000 K, the H- channel takes over H_2^+ in the production of 
molecular hydrogen. We calculate the critical radiation intensity needed for 
supermassive star formation by direct collapse and examine its 
dependence on the H_2^+ level population. Under the assumption of local 
thermodynamic equilibrium (LTE) level population, the critical intensity is 
underestimated by a factor of a few for soft spectra with Trad ? 7000 K. 
For harder spectra, the value of the critical intensity is not affected by the 
level population of H_2^+. This result justifies previous estimates of the 
critical intensity assuming LTE populations since radiation sources like 
young and/or metal-poor galaxies are predicted to have rather hard 
spectra.

Migrated from https://www.nublado.org/ticket/356

{
    "status": "new",
    "changetime": "2019-02-04T13:02:49Z",
    "_ts": "1549285369825011",
    "description": "{{{\nTitle:\t\nRole of the H_2^+ channel in the primordial star formation under strong radiation field and the critical intensity for the supermassive star formation\nAuthors:\t\nSugimura, K.; Coppola, C. M.; Omukai, K.; Galli, D.; Palla, F.\nAffiliation:\t\nAA(Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan sugimura@astr.tohoku.ac.jp), AB(Dipartimento di Chimica, Universit\u00e0 degli Studi di Bari, Via Orabona 4, I-70126 Bari, Italy; INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy), AC(Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan), AD(INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy), AE(INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy)\nPublication:\t\nMonthly Notices of the Royal Astronomical Society, Volume 456, Issue 1, p.270-277 (MNRAS Homepage)\nPublication Date:\t\n02/2016\nOrigin:\t\nOUP\nAstronomy Keywords:\t\nmolecular processes, quasars: supermassive black holes, cosmology: theory\nAbstract Copyright:\t\n2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society\nDOI:\t\n10.1093/mnras/stv2655\nBibliographic Code:\t\n2016MNRAS.456..270S\nAbstract\n\nWe investigate the role of the H_2^+ channel on H2 molecule formation \nduring the collapse of primordial gas clouds immersed in strong radiation \nfields which are assumed to have the shape of a diluted blackbody spectra \nwith temperature Trad. Since the photodissociation rate of H_2^+ depends \non its level population, we take full account of the vibrationally resolved \nH_2^+ kinetics. We find that in clouds under soft but intense radiation fields \nwith spectral temperature Trad ? 7000 K, the H_2^+ channel is the \ndominant H2 formation process. On the other hand, for harder spectra with \nTrad ? 7000 K, the H- channel takes over H_2^+ in the production of \nmolecular hydrogen. We calculate the critical radiation intensity needed for \nsupermassive star formation by direct collapse and examine its \ndependence on the H_2^+ level population. Under the assumption of local \nthermodynamic equilibrium (LTE) level population, the critical intensity is \nunderestimated by a factor of a few for soft spectra with Trad ? 7000 K. \nFor harder spectra, the value of the critical intensity is not affected by the \nlevel population of H_2^+. This result justifies previous estimates of the \ncritical intensity assuming LTE populations since radiation sources like \nyoung and/or metal-poor galaxies are predicted to have rather hard \nspectra.\n}}}",
    "reporter": "gary",
    "cc": "",
    "resolution": "",
    "time": "2016-01-07T20:47:36Z",
    "component": "atomic/molecular data base",
    "summary": "H2+ and primordial chemistry",
    "priority": "good to do",
    "keywords": "",
    "version": "trunk",
    "milestone": "no milestone",
    "owner": "nobody",
    "type": "enhancement"
}

cloudy-astrophysics / bug-tracker-migration-test

H2+ and primordial chemistry (trac #356) #358