2017/02/14 by Fabio Pacucci, Andrea Pallottini, A. Pallottini +3 · 2 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Metallicity #Photometry (optics) #Physics #Redshift #Star formation #Stars #astro-ph.CO #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.1093/mnrasl/slx029
published as MNRAS Letters, Volume 468, Issue 1, p. L77-L81 (2017) · Accepted for publication in MNRAS Letters
arxiv created 2017/02/14 · openalex publication_date 2017/02/16 · openalex created_date 2017/03/03 · arxiv updated 2017/08/25 · openalex updated_date 2026/08/05
Abstract The peculiar emission properties of the z ∼ 6.6 Lyα emitter COSMOS redshift 7 (CR7) have been initially interpreted with the presence of either a direct collapse black hole (DCBH) or a substantial mass of Pop III stars. Instead, updated photometric observations by Bowler et al. seem to suggest that CR7 is a more standard system. Here, we confirm that the original DCBH hypothesis is consistent also with the new data. Using radiation-hydrodynamic simulations, we reproduce the new infrared photometry with two models involving a Compton-thick DCBH of mass ≈7 × 106 M⊙ accreting (a) metal-free (Z = 0) gas with column density NH = 8 × 1025 cm−2 or (b) low-metallicity gas (Z = 5 × 10−3 Z⊙) with NH = 3 × 1024 cm−2. The best-fitting model reproduces the photometric data to within 1σ. Such metals can be produced by weak star-forming activity occurring after the formation of the DCBH. The main contribution to the Spitzer/IRAC 3.6 μm photometric band in both models is due to He i/He ii λλ4714, 4687 emission lines, while the contribution of [O iii] λλ4959, 5007 emission lines, if present, is sub-dominant. Spectroscopic observations with JWST will be required to ultimately clarify the nature of CR7.