2014MNRAS.442.2036D

The nature of the seeds of high-redshift supermassive black holes (SMBHs) is a key question in cosmology. Direct collapse black holes (DCBHs) that form in pristine, atomic-line cooling haloes, illuminated by a Lyman-Werner (LW) UV flux exceeding a critical threshold Jcrit represent an attractive possibility. We investigate when and where these conditions are met during cosmic evolution. For the LW intensity, JLW, we account for departures from the background value in close proximity to star-forming galaxies. For the pristine halo fraction, we account for both (i) supernova-driven outflows and (ii) the inherent pollution from progenitor haloes. We estimate the abundance of DCBH formation sites, nDCBH(z), and find that it increases with cosmic time from nDCBH(z = 20) ∼ 10^–12-10^–7 c/Mpc3 to nDCBH(z = 10) ∼ 10^–10-10^–5 c/Mpc3. Our analysis shows the possible importance of galactic winds, which can suppress the predicted nDCBH by several orders of magnitude, and cause DCBH formation to preferentially occur around the UV-brightest (MUV ∼ -21±1) star-forming galaxies. Our analysis further highlights the dependence of these predictions on (i) the escape fraction of LW photons, (ii) Jcrit, and (iii) the galactic outflow prescription.