2017ApJ...838..117N

Growing supermassive black holes (∼10⁹ M_☉) that power luminous z 6 quasars from light seeds-the remnants of the first stars-within a Gyr of the Big Bang poses a timing challenge. The formation of massive black hole seeds via direct collapse with initial masses ∼10⁴–10⁵ M_☉ alleviates this problem. Viable direct-collapse black hole formation sites, the satellite halos of star-forming galaxies, merge and acquire stars to produce a new, transient class of high-redshift objects, obese black hole galaxies (OBGs). The accretion luminosity outshines that of the stars in OBGs. We predict the multi-wavelength energy output of OBGs and growing Pop III remnants at z = 9 for standard and slim disk accretion, as well as high and low metallicities of the associated stellar population. We derive robust selection criteria for OBGs-a pre-selection to eliminate blue sources, followed by color-color cuts ([F_090W-F_220W] 0;-0.3 [F_200W-F_444W] 0.3) and the ratio of X-ray flux to rest-frame optical flux (F_X/F_444W≫1). Our cuts sift out OBGs from other bright, high- and low-redshift contaminants in the infrared. OBGs with predicted M_AB 25 are unambiguously detectable by the Mid-Infrared Instrument (MIRI), on the upcoming James Webb Space Telescope (JWST). For parameters explored here, growing Pop III remnants with predicted M_AB 30 will likely be undetectable by JWST. We demonstrate that JWST has the power to discriminate between initial seeding mechanisms.