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Title: Cosmos Redshift 7 is an Active Black Hole

Abstract

We present the first ab initio cosmological simulations of a CR7-like object which approximately reproduce the observed line widths and strengths. In our model, CR7 is powered by a massive (3:23 107 M ) black hole (BH) the accretion rate of which varies between ' 0.25 and ' 0.9 times the Eddington rate on timescales as short as 103 yr. Our model takes into account multi-dimensional effects, X-ray feedback, secondary ionizations and primordial chemistry. We estimate Ly- line widths by post-processing simulation output with Monte Carlo radiative transfer and calculate emissivity contributions from radiative recombination and collisional excitation. We find the luminosities in the Lyman- and He II 1640 angstrom lines to be 5:0 10 44 and 2:4 10 43 erg s -1, respectively, in agreement with the observed values of > 8:3 10 43 and 2:0 10 43 erg s -1. We also find that the black hole heats the halo and renders it unable to produce stars as required to keep the halo metal free. These results demonstrate the viability of the BH hypothesis for CR7 in a cosmological context. Assuming the BH mass and accretion rate that we find, we estimate the synchrotron luminosity of CR7 tomore » be P ' 10 40 - 10 41 erg s -1, which is sufficiently luminous to be observed in Jy observations and would discriminate this scenario from one where the luminosity is driven by Population III stars.« less

Authors:
 [1];  [2];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brigham Young Univ., Provo, UT (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1338773
Report Number(s):
LA-UR-16-21373
Journal ID: ISSN 2041-8213; TRN: US1701639
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 829; Journal Issue: 1; Journal ID: ISSN 2041-8213
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Galaxies

Citation Formats

Smidt, Joseph Michael, Wiggins, Brandon Kerry, and Johnson, Jarrett L. Cosmos Redshift 7 is an Active Black Hole. United States: N. p., 2016. Web. doi:10.3847/2041-8205/829/1/L6.
Smidt, Joseph Michael, Wiggins, Brandon Kerry, & Johnson, Jarrett L. Cosmos Redshift 7 is an Active Black Hole. United States. doi:10.3847/2041-8205/829/1/L6.
Smidt, Joseph Michael, Wiggins, Brandon Kerry, and Johnson, Jarrett L. 2016. "Cosmos Redshift 7 is an Active Black Hole". United States. doi:10.3847/2041-8205/829/1/L6. https://www.osti.gov/servlets/purl/1338773.
@article{osti_1338773,
title = {Cosmos Redshift 7 is an Active Black Hole},
author = {Smidt, Joseph Michael and Wiggins, Brandon Kerry and Johnson, Jarrett L.},
abstractNote = {We present the first ab initio cosmological simulations of a CR7-like object which approximately reproduce the observed line widths and strengths. In our model, CR7 is powered by a massive (3:23 107 M ) black hole (BH) the accretion rate of which varies between ' 0.25 and ' 0.9 times the Eddington rate on timescales as short as 103 yr. Our model takes into account multi-dimensional effects, X-ray feedback, secondary ionizations and primordial chemistry. We estimate Ly- line widths by post-processing simulation output with Monte Carlo radiative transfer and calculate emissivity contributions from radiative recombination and collisional excitation. We find the luminosities in the Lyman- and He II 1640 angstrom lines to be 5:0 1044 and 2:4 1043 erg s-1, respectively, in agreement with the observed values of > 8:3 1043 and 2:0 1043 erg s-1. We also find that the black hole heats the halo and renders it unable to produce stars as required to keep the halo metal free. These results demonstrate the viability of the BH hypothesis for CR7 in a cosmological context. Assuming the BH mass and accretion rate that we find, we estimate the synchrotron luminosity of CR7 to be P ' 1040 - 1041 erg s-1, which is sufficiently luminous to be observed in Jy observations and would discriminate this scenario from one where the luminosity is driven by Population III stars.},
doi = {10.3847/2041-8205/829/1/L6},
journal = {The Astrophysical Journal. Letters},
number = 1,
volume = 829,
place = {United States},
year = 2016,
month = 9
}

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Cited by: 7works
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  • Disk galaxies at high redshift have been predicted to maintain high gas surface densities due to continuous feeding by intense cold streams leading to violent gravitational instability, transient features, and giant clumps. Gravitational torques between the perturbations drive angular momentum out and mass in, and the inflow provides the energy for keeping strong turbulence. We use analytic estimates of the inflow for a self-regulated unstable disk at a Toomre stability parameter Q {approx} 1, and isolated galaxy simulations capable of resolving the nuclear inflow down to the central parsec. We predict an average inflow rate {approx}10 M{sub Sun} yr{sup -1}more » through the disk of a 10{sup 11} M{sub Sun} galaxy, with conditions representative of z {approx} 2 stream-fed disks. The inflow rate scales with disk mass and (1 + z){sup 3/2}. It includes clump migration and inflow of the smoother component, valid even if clumps disrupt. This inflow grows the bulge, while only a fraction of {approx}> 10{sup -3} of it needs to accrete onto a central black hole (BH), in order to obey the observed BH-bulge relation. A galaxy of 10{sup 11} M{sub Sun} at z {approx} 2 is expected to host a BH of {approx}10{sup 8} M{sub Sun }, accreting on average with moderate sub-Eddington luminosity L{sub X} {approx} 10{sup 42}-10{sup 43} erg s{sup -1}, accompanied by brighter episodes when dense clumps coalesce. We note that in rare massive galaxies at z {approx} 6, the same process may feed {approx}10{sup 9} M{sub Sun} BH at the Eddington rate. High central gas column densities can severely obscure active galactic nuclei in high-redshift disks, possibly hindering their detection in deep X-ray surveys.« less
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