Detecting direct collapse black holes: making the case for CR7
van den Bosch, Frank C.; Natarajan, Priyamvada; Zackrisson, Erik; Labbe, Ivo; Khochfar, Sadegh; Agarwal, Bhaskar; Johnson, Jarrett L.
United States, Sweden, Netherlands, United Kingdom
Abstract
We propose that one of the sources in the recently detected system CR7 by Sobral et al. through spectrophotometric measurements at z = 6.6 harbours a direct collapse black hole (DCBH). We argue that the LW radiation field required for direct collapse in source A is provided by sources B and C. By tracing the LW production history and star formation rate over cosmic time for the halo hosting CR7 in a ΛCDM universe, we demonstrate that a DCBH could have formed at z ∼ 20. The spectrum of source A is well fit by nebular emission from primordial gas around a BH with MBH ∼4.4 × 106 M⊙ accreting at a 40 per cent of the Eddington rate, which strongly supports our interpretation of the data. Combining these lines of evidence, we argue that CR7 might well be the first DCBH candidate.