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Title: Suppression of H2-cooling in protogalaxies aided by trapped Ly-alpha cooling radiation
We study the thermal evolution of UV-irradiated atomic cooling haloes using high-resolution three-dimensional hydrodynamic simulations. We consider the effect of H^- photodetachment by Ly{\alpha} cooling radiation trapped in the optically-thick cores of three such haloes, a process which has not been included in previous simulations. H^- is a precursor of molecular hydrogen, and therefore, its destruction can diminish the H2 abundance and cooling. Using a simple high-end estimate for the trapped Ly{\alpha} energy density, we find that H^- photodetachment by Ly{\alpha} decreases the critical UV flux for suppressing H2-cooling by up to a factor of \approx 5. With a more conservative estimate of the Ly{\alpha} energy density, we find the critical flux is decreased only by ~15-50 percent. Our results suggest that Ly{\alpha} radiation may have an important effect on the thermal evolution of UV-irradiated haloes, and therefore on the potential for massive black hole formation.  more » « less
Award ID(s):
1903935
PAR ID:
10158992
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
ArXivorg
ISSN:
2331-8422
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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