4 research outputs found
J1406+0102: Dust Obscured Galaxy Hiding Super Eddington Accretion System with Bright Radio Emission
Recent high- quasar observations strongly indicate that super-Eddington
accretion is a crucial phase to describe the existence of supermassive black
holes (SMBHs) with at .
Motivated by the theoretical suggestion that the super-Eddington phase
efficiently produces outflows and jets bright in radio bands, we search and
find a super-Eddington radio-loud dust-obscured galaxy (DOG) J1406+0102 at
, through cross-matching of the infrared-bright DOGs of Noboriguchi et
al. (2019) with the VLA/FIRST 1.4 GHz radio and the SDSS optical spectral
catalog. DOG J1406+0102 shows broad components in the Balmer lines. Assuming
those lines are from the broad line region, it gives BH mass estimation of
, and AGN luminosity of estimated from the intrinsic [OIII] luminosity, resulting in
super-Eddington accretion of . We show that 1)
DOG J1406+0102 is operating strong AGN feedback: the [OIII] outflow velocity
exceeds the escape velocity of the host galaxy halo and the kinetic efficiency
is obtained as 8% that can be sufficient to quench the host galaxy,
2) the expected future growth pathway of DOG J1406+0102 would join an
over-massive BH trajectory and 3) radio-loud DOGs can provide a significant
contribution to the high-energy ( 100 TeV) cosmic neutrino background
if we assume DOG J1406+0102 as a representative of radio-loud DOGs.Comment: 10 pages, 5 figures, submitted to ApJ
Tracing the rise of supermassive black holes A panchromatic search for faint, unobscured quasars at z & 6 with COSMOS-Web and other surveys
We report the identification of 64 new candidates of compact galaxies, potentially hosting faint quasars with bolometric luminosities of Lbol = 1043–1046 erg s−1, 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 ≈105–107 M supermassive black holes (SMBHs) living in galaxies with stellar masses of ≈108–1010 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 ≈ 7. Notably, most of the selected candidates might have emerged from seeds with masses of ∼105 M , assuming a thin disk accretion with an average Eddington ratio of fEdd = 0.6±0.3 and a radiative efficiency of ε = 0.2±0.1. 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.</p
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Tracing the rise of supermassive black holes: a panchromatic search for faint, unobscured quasars at z & 6 with COSMOS-Web and other surveys
We report the identification of 64 new candidates of compact galaxies, potentially hosting faint quasars with bolometric luminosities of Lbol = 1043–1046 erg s−1, 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 ≈105–107 M supermassive black holes (SMBHs) living in galaxies with stellar masses of ≈108–1010 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 ≈ 7. Notably, most of the selected candidates might have emerged from seeds with masses of ∼105 M , assuming a thin disk accretion with an average Eddington ratio of fEdd = 0.6±0.3 and a radiative efficiency of ε = 0.2±0.1. 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.</p