scholarly journals A rapidly evolving quasar population at the epoch of reionzation

2019 ◽  
Vol 15 (S352) ◽  
pp. 126-126
Author(s):  
Xiaohui Fan
Keyword(s):  
Black Hole ◽  
High Redshift ◽  
Rapid Evolution ◽  
Large Area ◽  
Supermassive Black Hole ◽  
Diverse Environment ◽  
Area Survey ◽  
Statistical Sample ◽  
Massive Galaxy ◽  
Observation Results

AbstractI will present results from our on-going large area survey of high-redshift quasars, which has discovered more than 20 new quasars at z > 6.5, at the epoch of reionization, forming the first large statistical sample of EoR quasars. I will discuss the rapid evolution of quasar density at that epoch, which suggests that we are witnessing the emergence of the first supermassive black hole population. I will also present multiwavelength followup observation results, especially from ALMA and Chandra, which reveals a diverse environment of quasar activities and yields new insights into the supermassive black hole/massive galaxy co-evolution.

scholarly journals A Catastrophic Failure to Build a Massive Galaxy around a Supermassive Black Hole at z = 3.84

2019 ◽  
Vol 881 (2) ◽  
pp. 145
Author(s):  
M. Schramm ◽  
W. Rujopakarn ◽  
J. D. Silverman ◽  
T. Nagao ◽  
A. Schulze ◽  
...  
Keyword(s):  
Black Hole ◽  
Catastrophic Failure ◽  
Supermassive Black Hole ◽  
Massive Galaxy

scholarly journals Global torques and stochasticity as the drivers of massive black hole pairing in the young Universe

2020 ◽  
Vol 498 (3) ◽  
pp. 3601-3615 ◽  
Author(s):  
Elisa Bortolas ◽  
Pedro R Capelo ◽  
Tommaso Zana ◽  
Lucio Mayer ◽  
Matteo Bonetti ◽  
...  
Keyword(s):  
Black Hole ◽  
Large Scale ◽  
High Redshift ◽  
Dynamical Evolution ◽  
Dynamical Friction ◽  
Massive Black Hole ◽  
Orbital Decay ◽  
Orbital Phase ◽  
Order Of Magnitude ◽  
Statistical Sample

ABSTRACT The forthcoming Laser Interferometer Space Antenna (LISA) will probe the population of coalescing massive black hole (MBH) binaries up to the onset of structure formation. Here, we simulate the galactic-scale pairing of ∼106 M⊙ MBHs in a typical, non-clumpy main-sequence galaxy embedded in a cosmological environment at z = 7–6. In order to increase our statistical sample, we adopt a strategy that allows us to follow the evolution of six secondary MBHs concomitantly. We find that the magnitude of the dynamical-friction-induced torques is significantly smaller than that of the large-scale, stochastic gravitational torques arising from the perturbed and morphologically evolving galactic disc, suggesting that the standard dynamical friction treatment is inadequate for realistic galaxies at high redshift. The dynamical evolution of MBHs is very stochastic, and a variation in the initial orbital phase can lead to a drastically different time-scale for the inspiral. Most remarkably, the development of a galactic bar in the host system either significantly accelerates the inspiral by dragging a secondary MBH into the centre, or ultimately hinders the orbital decay by scattering the MBH in the galaxy outskirts. The latter occurs more rarely, suggesting that galactic bars overall promote MBH inspiral and binary coalescence. The orbital decay time can be an order of magnitude shorter than what would be predicted relying on dynamical friction alone. The stochasticity and the important role of global torques have crucial implications for the rates of MBH coalescences in the early Universe: both have to be accounted for when making predictions for the upcoming LISA observatory.

A Photoionization Method for Estimating Black Hole Masses in Quasars

2018 ◽  
Vol 14 (S342) ◽  
pp. 270-271
Author(s):  
C. Alenka Negrete ◽  
Deborah Dultzin ◽  
Paola Marziani ◽  
Jack W. Sulentic ◽  
M. L. Martínez-Aldama
Keyword(s):  
Black Hole ◽  
High Redshift ◽  
Broad Line ◽  
Reverberation Mapping ◽  
Physical Conditions ◽  
Broad Line Region ◽  
Supermassive Black Hole ◽  
Line Region ◽  
Black Hole Masses

AbstractWe present a method that uses photoionization codes (CLOUDY) to estimate the supermassive black hole masses (MBH) for quasars at low and high redshift. This method is based on the determination of the physical conditions of the broad line region (BLR) using observational diagnostic diagrams from line ratios in the UV. We also considered that the density and metallicity of the BLR in quasars at high z could be different from those at the nearby Universe. The computed black hole masses obtained using this method are in agreement with those derived from the method of reverberation mapping.

scholarly journals On the Absence of High-redshift AGNs: Little Growth in the Supermassive Black Hole Population at High Redshifts

2020 ◽  
Vol 891 (1) ◽  
pp. 69 ◽  
Author(s):  
L. L. Cowie ◽  
A. J. Barger ◽  
F. E. Bauer ◽  
J. González-López
Keyword(s):  
Black Hole ◽  
High Redshift ◽  
Supermassive Black Hole

scholarly journals ACCRETION ONTO THE SUPERMASSIVE BLACK HOLE IN THE HIGH-REDSHIFT RADIO-LOUD AGN 0957+561

2011 ◽  
Vol 744 (1) ◽  
pp. 47 ◽  
Author(s):  
Rodrigo Gil-Merino ◽  
Luis J. Goicoechea ◽  
Vyacheslav N. Shalyapin ◽  
Vittorio F. Braga
Keyword(s):  
Black Hole ◽  
High Redshift ◽  
Supermassive Black Hole

scholarly journals Multifrequency filter search for high redshift sources and lensing systems in Herschel-ATLAS

2019 ◽  
Vol 622 ◽  
pp. A106
Author(s):  
A. Manjón-García ◽  
D. Herranz ◽  
J. M. Diego ◽  
L. Bonavera ◽  
J. González-Nuevo
Keyword(s):  
Signal To Noise Ratio ◽  
High Redshift ◽  
Simulated Data ◽  
Galaxy Cluster ◽  
Point Sources ◽  
Sloan Digital Sky Survey ◽  
Large Area ◽  
Redshift Range ◽  
Photometric Redshift ◽  
Area Survey

We present a new catalog of high-redshift candidate Herschel sources. Our sample is obtained after applying a multifrequency filtering method (“matched multifilter”), which is designed to improve the signal-to-noise ratio of faint extragalactic point sources. The method is tested against already-detected sources from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and used to search for new high-redshift candidates. The multifilter technique also produces an estimation of the photometric redshift of the sources. When compared with a sample of sources with known spectroscopic redshift, the photometric redshift returned from the multifilter is unbiased in the redshift range 0.8 <  z <  4.3. Using simulated data we reproduced the same unbiased result in roughly the same redshift range and determined the error (and bias above z ≈ 4) in the photometric redshifts. Based on the multifilter technique, and a selection based on color, flux, and agreement of fit between the observed photometry and assumed SED, we find 370 robust candidates to be relatively bright high-redshift sources. A second sample with 237 objects focuses on the faint end at high-redshift. These 237 sources were previously near the H-ATLAS detection limit but are now confirmed with our technique as high significance detections. Finally, we look for possible lensed Herschel sources by cross-correlating the first sample of 370 objects with two different catalogs of known low-redshift objects, the redMaPPer Galaxy Cluster Catalog and a catalog of galaxies with spectroscopic redshift from the Sloan Digital Sky Survey Data Release 14. Our search renders a number of candidates to be lensed systems from the SDSS cross-correlation but none from the redMaPPeR confirming the more likely galactic nature of the lenses.

scholarly journals Chandra reveals a luminous Compton-thick QSO powering a Lyα blob in a z = 4 starbursting protocluster

2020 ◽  
Vol 642 ◽  
pp. A149
Author(s):  
F. Vito ◽  
W. N. Brandt ◽  
B. D. Lehmer ◽  
C. Vignali ◽  
F. Zou ◽  
...  
Keyword(s):  
Black Hole ◽  
High Redshift ◽  
High Rate ◽  
Host Galaxies ◽  
Gas Reservoirs ◽  
Nuclear Activity ◽  
X Ray ◽  
Supermassive Black Hole ◽  
Nuclear Regions ◽  
Massive Outflow

Context. Galaxy clusters in the local universe descend from high-redshift overdense regions known as protoclusters. The large gas reservoirs and high rate of galaxy interaction in protoclusters are expected to enhance star-formation activity and trigger luminous supermassive black-hole accretion in the nuclear regions of the host galaxies. Aims. We investigated the active galactic nucleus (AGN) content of a gas-rich and starbursting protocluster at z = 4.002, known as the Distant Red Core (DRC). In particular, we search for luminous and possibly obscured AGN in 13 identified members of the structure, and compare the results with protoclusters at lower redshifts. We also test whether a hidden AGN can power the Lyα blob (LAB) detected with VLT/MUSE in the DRC. Methods. We observed all of the identified members of the structure with 139 ks of Chandra ACIS-S imaging. Being less affected by absorption than optical and IR bands, even in the presence of large column densities of obscuring material, X-ray observations are the best tools to detect ongoing nuclear activity in the DRC galaxies. Results. We detect obscured X-ray emission from the two most gas-rich members of the DRC, named DRC-1 and DRC-2. Both of them are resolved into multiple interacting clumps in high-resolution Atacama Large Millimeter Array and Hubble Space Telescope observations. In particular, DRC-2 is found to host a luminous (L2−10 keV ≈ 3 × 1045 erg s−1 ) Compton-thick (NH ≳ 1024 cm−2) quasar (QSO) candidate, comparable to the most luminous QSOs known at all cosmic times. The AGN fraction among DRC members is consistent with results found for lower redshift protoclusters. However, X-ray stacking analysis reveals that supermassive black hole (SMBH) accretion is likely also taking place in other DRC galaxies that are not detected individually by Chandra. Conclusions. The luminous AGN detected in the most gas-rich galaxies in the DRC and the widespread SMBH accretion in the other members, which is suggested by stacking analysis, point toward the presence of a strong link between large gas reservoirs, galaxy interactions, and luminous and obscured nuclear activity in protocluster members. The powerful and obscured QSO detected in DRC-2 is likely powering the nearby LAB detected with VLT/MUSE, possibly through photoionization; however, we propose that the diffuse Lyα emission may be due to gas shocked by a massive outflow launched by DRC-2 over a ≈10 kpc scale.

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