TY - JOUR
T1 - High-redshift Galaxies and Black Holes Detectable with the JWST
T2 - A Population Synthesis Model from Infrared to X-Rays
AU - Volonteri, Marta
AU - Reines, Amy E.
AU - Atek, Hakim
AU - Stark, Daniel P.
AU - Trebitsch, Maxime
N1 - Funding Information:
We are grateful to the reviewer for the suggestions and careful reading of the manuscript. M.V. warmly thanks Matt Lehnert for helping her unravel the mystery of magnitudes, “a quaint unit of historical interest,” cit.Cloudy & Associates (http://www.nublado.org), Alice Shapley for thoughtful conversations and her kind help with galaxy spectra, Roberto Gilli, Claudia Maraston, and Roberto Decarli for constructive discussions and comments on the manuscript, and F. Vito and B. Lehmer for help with HMXBs. M.V. and M.T. acknowledge funding from the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013 Grant Agreement no. 614199, project “BLACK”). A.E.R. is grateful for the support of NASA through Hubble Fellowship grant HST-HF2-51347.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555.
PY - 2017/11/10
Y1 - 2017/11/10
N2 - The first billion years of the Universe has been a pivotal time: stars, black holes (BHs), and galaxies formed and assembled, sowing the seeds of galaxies as we know them today. Detecting, identifying, and understanding the first galaxies and BHs is one of the current observational and theoretical challenges in galaxy formation. In this paper we present a population synthesis model aimed at galaxies, BHs, and active galactic nuclei (AGNs) at high redshift. The model builds a population based on empirical relations. The spectral energy distribution of galaxies is determined by age and metallicity, and that of AGNs by BH mass and accretion rate. We validate the model against observations, and predict properties of galaxies and AGN in other wavelength and/or luminosity ranges, estimating the contamination of stellar populations (normal stars and high-mass X-ray binaries) for AGN searches from the infrared to X-rays, and vice versa for galaxy searches. For high-redshift galaxies with stellar ages < Gyr, we find that disentangling stellar and AGN emission is challenging at restframe UV/optical wavelengths, while high-mass X-ray binaries become more important sources of confusion in X-rays. We propose a color-color selection in the James Webb Space Telescope bands to separate AGN versus star-dominated galaxies in photometric observations. We also estimate the AGN contribution, with respect to massive, hot, and metal-poor stars, at driving high-ionization lines, such as C iv and He ii. Finally, we test the influence of the minimum BH mass and occupation fraction of BHs in low-mass galaxies on the restframe UV/near-IR and X-ray AGN luminosity function.
AB - The first billion years of the Universe has been a pivotal time: stars, black holes (BHs), and galaxies formed and assembled, sowing the seeds of galaxies as we know them today. Detecting, identifying, and understanding the first galaxies and BHs is one of the current observational and theoretical challenges in galaxy formation. In this paper we present a population synthesis model aimed at galaxies, BHs, and active galactic nuclei (AGNs) at high redshift. The model builds a population based on empirical relations. The spectral energy distribution of galaxies is determined by age and metallicity, and that of AGNs by BH mass and accretion rate. We validate the model against observations, and predict properties of galaxies and AGN in other wavelength and/or luminosity ranges, estimating the contamination of stellar populations (normal stars and high-mass X-ray binaries) for AGN searches from the infrared to X-rays, and vice versa for galaxy searches. For high-redshift galaxies with stellar ages < Gyr, we find that disentangling stellar and AGN emission is challenging at restframe UV/optical wavelengths, while high-mass X-ray binaries become more important sources of confusion in X-rays. We propose a color-color selection in the James Webb Space Telescope bands to separate AGN versus star-dominated galaxies in photometric observations. We also estimate the AGN contribution, with respect to massive, hot, and metal-poor stars, at driving high-ionization lines, such as C iv and He ii. Finally, we test the influence of the minimum BH mass and occupation fraction of BHs in low-mass galaxies on the restframe UV/near-IR and X-ray AGN luminosity function.
KW - galaxies: active
KW - galaxies: evolution
KW - galaxies: high-redshift
UR - http://www.scopus.com/inward/record.url?scp=85034434691&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85034434691&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aa93f1
DO - 10.3847/1538-4357/aa93f1
M3 - Article
AN - SCOPUS:85034434691
VL - 849
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 155
ER -