Tracing the rise of supermassive black holes

Abstract

We report the identification of 64 new candidates of compact galaxies, potentially hosting faint quasars with bolometric luminosities of $L_ bol $--1046 erg s$^ $, residing in the reionization epoch within the redshift range of $6 z 8$. These candidates were selected by harnessing the rich multiband datasets provided by the emerging JWST-driven extragalactic surveys, focusing on COSMOS-Web, as well as JADES, UNCOVER, CEERS, and PRIMER. Our search strategy includes two stages: applying stringent photometric cuts to catalog-level data and detailed spectral energy distribution fitting. These techniques effectively isolate the quasar candidates while mitigating contamination from low-redshift interlopers, such as brown dwarfs and nearby galaxies. The selected candidates indicate physical traits compatible with low-luminosity active galactic nuclei, likely hosting $ M_ supermassive black holes (SMBHs) living in galaxies with stellar masses of $ M_ The SMBHs selected in this study, on average, exhibit an elevated mass compared to their hosts, with the mass ratio distribution slightly higher than those of galaxies in the local Universe. As with other high-$z$ studies, this is at least in part due to the selection method for these quasars. An extensive Monte Carlo analysis provides compelling evidence that heavy black hole seeds from the direct collapse scenario appear to be the preferred pathway to mature this specific subset of SMBHs by $z Notably, most of the selected candidates might have emerged from seeds with masses of $ M_ assuming a thin disk accretion with an average Eddington ratio of $f_ Edd and a radiative efficiency of $ This work underscores the significance of further spectroscopic observations, as the quasar candidates presented here offer exceptional opportunities to delve into the nature of the earliest galaxies and SMBHs that formed during cosmic infancy.

From Seeds to Supermassive Black Holes: Capture, Growth, Migration, and Pairing in Dense Protobulge Environments

“…But observations will be challenging, since we predict that this occurs on short time and small spatial scales in high-redshift systems, with comparable stellar and BH accretion bolometric luminosity, and the medium is still dusty and obscured at these times owing to the high gas densities. Still, it is immediately striking that the bolometric luminosities (∼5-50 × 10 44 erg s −1 , depending on the BH radiative efficiency), sizes (∼10-100 pc), broadly comparable mix of stellar and active galactic nucleus luminosity, and colors (given the predicted dust column densities at large radii from Figure 4) this simulation would exhibit during its later evolution (0.7 Myr, after coalescence and disk formation) are all remarkably consistent with the observed properties of the unexpected population of "little red dots" seen by JWST at redshifts z ∼ 4-10 (compare, e.g., Andika et al 2024;Kocevski et al 2024;Kokorev et al 2024).…”

A Census of Photometrically Selected Little Red Dots at 4 < z < 9 in JWST Blank Fields

“…For example, in GOODS-S, Matthee et al (2024) report an average σ z = |Δz|/(1 + z spec ) = 0.01, and UNCOVER LRDs presented in Greene et al (2024) have shown σ z ∼ 0.04. A similar consistency was also found between the initial photometric source selection and final spectra in the JADES and CEERS fields (Kocevski et al 2023;Andika et al 2024;Maiolino et al 2024). As such, we consider that utilizing EAZY to derive redshifts is adequate for our sample.…”

“…Using observed NIR colors to pick out active BHs in extragalactic fields is by no means a novel endeavor and has already been successfully done with the IRAC instrument on board the Spitzer Space Telescope (Lacy et al 2004;Stern et al 2005;Donley et al 2012). This method, however, is still in its infancy when it comes to JWST (Labbé et al 2023a;Andika et al 2024). As already pointed out by Matthee et al (2024), very few JWST programs that detect dusty AGN were actually designed with AGN in mind, implying that there is still more that we can do to address a growing number of questions about this population.…”