| 1. |
- Nabizadeh, Armin, et al.
(författare)
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A search for high-redshift direct-collapse black hole candidates in the PEARLS north ecliptic pole field
- 2024
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 683
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Tidskriftsartikel (refereegranskat)abstract
- Direct-collapse black holes (DCBHs) of mass ∼ 104-105 M⊙ that form in HI-cooling halos in the early Universe are promising progenitors of the greater than or similar to 109 M⊙ supermassive black holes that fuel observed z greater than or similar to 7 quasars. Efficient accretion of the surrounding gas onto such DCBH seeds may render them sufficiently bright for detection with the JWST up to z ≈ 20. Additionally, the very steep and red spectral slope predicted across the ≈ 1-5 μm wavelength range of the JWST/NIRSpec instrument during their initial growth phase should make them photometrically identifiable up to very high redshifts. In this work, we present a search for such DCBH candidates across the 34 arcmin2 in the first two spokes of the JWST cycle-1 PEARLS survey of the north ecliptic pole time-domain field covering eight NIRCam filters down to a maximum depth of ∼ 29 AB mag. We identify two objects with spectral energy distributions consistent with the Pacucci et al. (2016) DCBH models. However, we also note that even with data in eight NIRCam filters, objects of this type remain degenerate with dusty galaxies and obscured active galactic nuclei over a wide range of redshifts. Follow-up spectroscopy would be required to pin down the nature of these objects. Based on our sample of DCBH candidates and assumptions on the typical duration of the DCBH steep-slope state, we set a conservative upper limit of less than or similar to 5x10-4 comoving Mpc-3 (cMpc-3) on the comoving density of host halos capable of hosting DCBHs with spectral energy distributions similar to the Pacucci et al. (2016) models at z ≈ 6-14.
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| 2. |
- Natarajan, Priyamvada, et al.
(författare)
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Unveiling the First Black Holes With JWST : Multi-wavelength Spectral Predictions
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 838:2
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Tidskriftsartikel (refereegranskat)abstract
- Growing supermassive black holes (similar to 10(9) M-circle dot) 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 similar to 10(4)-10(5) M-circle dot 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.
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| 3. |
- Whalen, Daniel J., et al.
(författare)
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Finding Direct-collapse Black Holes at Birth
- 2020
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 897:1
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Tidskriftsartikel (refereegranskat)abstract
- Direct-collapse black holes (DCBHs) are currently one of the leading contenders for the origins of the first quasars in the universe, over 300 of which have now been found at z > 6. But the birth of a DCBH in an atomically cooling halo does not by itself guarantee it will become a quasar by z similar to 7, the halo must also be located in cold accretion flows or later merge with a series of other gas-rich halos capable of fueling the BH's rapid growth. Here, we present near-infrared luminosities for DCBHs born in cold accretion flows in which they are destined to grow to 10(9) M-circle dot by z similar to 7. Our observables, which are derived from cosmological simulations with radiation hydrodynamics with Enzo, reveal that DCBHs could be found by the James Webb Space Telescope at z less than or similar to 20 and strongly lensed DCBHs might be found in future wide-field surveys by Euclid and the Wide-Field Infrared Space Telescope at z less than or similar to 15.
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