Intergalactic H_2 Photodissociation and the Soft UV Background Produced by Population III Objects

dc.creatorCiardi, Benedetta
dc.creatorFerrara, Andrea
dc.creatorAbel, Tom
dc.date1998-11-09
dc.date1999-04-09
dc.date.accessioned2026-07-07T02:29:00Z
dc.date.available2026-07-07T02:29:00Z
dc.descriptionWe study the effects of the ionizing and dissociating photons produced by PopIII objects on the surrounding intergalactic medium. We find that the typical size of a H_2 photodissociated region, R_d ~ 1-5 kpc, is smaller than the mean distance between sources at z ~ 20-30, but larger than the ionized region by a factor depending on the detailed properties of the emission spectrum. This implies that clearing of intergalactic H_2 occurs before reionization of the universe is complete. In the same redshift range, the soft-UV background in the Lyman-Werner bands, when the intergalactic H and H_2 opacity is included, is found to be J_LW ~ 1d-30 - 1d-27 erg cm^{-2} s^{-1} Hz^{-1}. This value is well below the threshold required for the negative feedback of PopIII objects on the subsequent galaxy formation to be effective in that redshift range.
dc.description13 pages, 7 figures; accepted for publication in ApJ. Final version with minor modifications of Fig. 5 & 6
dc.identifierhttps://arxiv.org/abs/astro-ph/9811137
dc.identifierhttp://arxiv.org/abs/astro-ph/9811137
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/13299
dc.subjectAstrophysics
dc.titleIntergalactic H_2 Photodissociation and the Soft UV Background Produced by Population III Objects
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