The Age of Discovery with the James Webb: Excavating the Spectral Signatures of the First Massive Black Holes

Abstract

The James Webb Space Telescope (JWST) will open a new window of the most distant universe and unveil the early growth of supermassive black holes (BHs) in the first galaxies. In preparation for deep JWST imaging surveys, it is crucial to understand the color selection of high-redshift accreting seed BHs. We model the spectral energy distribution of super-Eddington accreting BHs with millions of solar masses in metal-poor galaxies at $z\gtrsim 8$, applying post-process line transfer calculations to radiation hydrodynamical simulation results. Ten kilosecond exposures with the NIRCam and MIRI broad-band filters are sufficient to detect the radiation flux from the seed BHs with bolometric luminosities of $L_{\mathrm{bol}}\simeq 10^{45}{\mathrm{erg}\mathrm{s}}^{-1}$. While the continuum colors are similar to those of typical low-$z$ quasars, strong H$\alpha$ line emission with a rest-frame equivalent width ${\mathrm{EW}}_{\mathrm{rest}}\simeq 1300\mathring{A}$ is so prominent that the line flux affects the broad-band colors significantly. The unique colors, for instance F356W$-$F560W $\gtrsim 1$ at $7<z<8$ and F444W$-$F770W $\gtrsim 1$ at $9<z<12$, provide robust criteria for photometric selection of the rapidly growing seed BHs. Moreover, NIRSpec observations of low-ionization emission lines can test whether the BH is fed via a dense accretion disk at super-Eddington rates.

arXiv comment10 pages, 5 figures, 1 table, accepted for publication in ApJL

References in corpus (32)

• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• Composite Quasar Spectra From the Sloan Digital Sky Survey
• An 800-million-solar-mass black hole in a significantly neutral Universe at redshift 7.5
• Models of Stars, Brown Dwarfs and Exoplanets
• Estimating Black Hole Masses in Active Galaxies Using the Halpha Emission Line
• An ultra-luminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30
• The Assembly of the First Massive Black Holes
• A Luminous Quasar at Redshift 7.642
• Rest-frame ultraviolet-to-optical spectral characteristics of extremely metal-poor and metal-free galaxies
• The origins of massive black holes
• The first ultraviolet quasar stacked spectrum at z=2.4 from WFC3
• Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). V. Quasar Luminosity Function and Contribution to Cosmic Reionization at z = 6
• Subaru high-z exploration of low-luminosity quasars (SHELLQs). I. Discovery of 15 quasars and bright galaxies at 5.7 < z < 6.9
• An X-shooter composite of bright 1 < z < 2 quasars from UV to infrared
• Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). VI. Black Hole Mass Measurements of Six Quasars at 6.1<z<6.7
• Unveiling the first black holes with JWST: multi-wavelength spectral predictions
• Shining in the Dark: the Spectral Evolution of the First Black Holes
• Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). XIII. Large-scale Feedback and Star Formation in a Low-Luminosity Quasar at z = 7.07 on the Local Black Hole to Host Mass Relation
• Numerical resolution effects on simulations of massive black hole seeds
• A Revised Calibration of the Virial Mass Estimator for Black Holes in Active Galaxies Based on Single-epoch H$\beta$ Spectra
• Co-evolution of massive black holes and their host galaxies at high redshift: discrepancies from six cosmological simulations and the key role of JWST
• Light, medium-weight or heavy? The nature of the first supermassive black hole seeds
• ALMA Lensing Cluster Survey: Bright [CII] 158 $\mu$m Lines from a Multiply Imaged Sub-$L^{\star }$ Galaxy at $z=6.0719$
• Rapid growth of seed black holes during early bulge formation
• Chasing the observational signatures of seed black holes at z > 7: candidate statistics
• Chasing the observational signatures of seed black holes at z > 7: candidate observability
• Intermediate-mass black holes from Population III remnants in the first galactic nuclei
• Observational signatures of massive black hole formation in the early universe
• Balmer Break Galaxy Candidates at $z\sim 6$: a Potential View on the Star-Formation Activity at $z\gtrsim 14$
• Super-Eddington growth of black holes in the early Universe: effects of disk radiation spectra
• Simulating JWST/NIRCam Color Selection of High-Redshift Galaxies
• The ALPINE-ALMA [CII] Survey: the population of [CII]-undetected galaxies and their role in the ${\mathrm{L}}_{[\mathrm{CII}]}$-SFR relation

Cited by in corpus (11)

• A Lower Bound of Star Formation Activity in Ultra-high Redshift Galaxies Detected with JWST: Implications for Stellar Populations and Radiation Sources
• A Candidate of a Least-Massive Black Hole at the First 1.1 Billion Years of the Universe
• RUBIES: JWST/NIRSpec Confirmation of an Infrared-luminous, Broad-line Little Red Dot with an Ionized Outflow
• Seeking the growth of the first black hole seeds with JWST
• Supercritical growth pathway to overmassive black holes at cosmic dawn: coevolution with massive quasar hosts
• Probing the $z\gtrsim 6$ quasars in a universe with IllustrisTNG physics: Impact of gas-based black hole seeding models
• "Little red dots" cannot reside in the same dark matter halos as comparably luminous unobscured quasars
• How long do high-redshift massive black hole seeds remain outliers in black hole vs. host galaxy relations?
• Little Red Dots as Direct-collapse Black Hole Nurseries
• Bulgeless disks, dark galaxies, inverted color gradients, and other expected phenomena at higher z. The chromatic surface brightness modulation (CMOD) effect
• An empirical approach to selecting the first growing black hole seeds with JWST/NIRCam