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Related papers: Exploring New Redshift Indicators for Radio-Powerf…

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Recent calculations indicate that radio emission from quasars at $z \sim$ 6 - 7 could be detected at much earlier stages of evolution, at $z \sim$ 14 - 15, by the Next-Generation Very Large Array (ngVLA) and the Square Kilometer Array…

Astrophysics of Galaxies · Physics 2024-04-10 Muhammad A. Latif , Ammara Aftab , Daniel J. Whalen

We study whether hierarchical galaxy formation in a concordance $\Lambda$CDM universe can produce enough massive and red galaxies compared to the observations. We implement a semi-analytical model in which the central black holes gain their…

Astrophysics · Physics 2008-11-26 X. Kang , Y. P. Jing , J. Silk

Active Galactic Nuclei (AGNs) are among the most luminous objects in the universe, making them valuable probes for studying galaxy evolution. However, understanding how AGN properties evolve over cosmic time remains a fundamental challenge.…

Astrophysics of Galaxies · Physics 2025-05-06 Shreya Sareen , Swayamtrupta Panda

The perfect case for time-domain investigations are active galactic nuclei (AGNs) since they are luminous objects that show strong variability. Key result from the studies of AGNs variability is the estimated mass of a supermassive black…

High Energy Astrophysical Phenomena · Physics 2021-05-05 D. Ilic , A. Kovacevic , L. C. Popovic

We show that mid-infrared data from the all-sky WISE survey can be used as a robust photometric redshift indicator for powerful radio AGN, in the absence of other spectroscopic or multi-band photometric information. Our work is motivated by…

Instrumentation and Methods for Astrophysics · Physics 2017-09-27 M. Glowacki , J. R. Allison , E. M. Sadler , V. A. Moss , T. H. Jarrett

We explore the evolution with redshift of the rest-frame colours and space densities of AGN hosts (relative to normal galaxies) to shed light on the dominant mechanism that triggers accretion onto supermassive black holes as a function of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 A. Georgakakis , A. L. Coil , C. N. A. Willmer , K. Nandra , D. D. Kocevski , M. C. Cooper , D. J. Rosario , D. C. Koo , J. R. Trump , S. Juneau

Context. Active galactic nuclei (AGNs) and star forming galaxies (SFGs) are the primary sources of extragalactic radio sky. But it is difficult to distinguish the radio emission produced by AGNs from that by SFGs, especially when the radio…

Astrophysics of Galaxies · Physics 2025-09-17 Xu-Liang Fan , Jie Li

Determinations of the UV luminosity function of AGN at high redshifts are important for constraining the AGN contribution to reionization and understanding the growth of supermassive black holes. Recent inferences of the luminosity function…

Astrophysics of Galaxies · Physics 2019-06-12 Girish Kulkarni , Gábor Worseck , Joseph F. Hennawi

Recent JWST observations have unveiled a numerous population of low-luminosity active galactic nuclei (AGN) at $4< z<10$, with space densities roughly an order of magnitude above pre-JWST estimates, and many of these AGN have masses orders…

From a parent catalog of 561 changing-look active galactic nuclei (CL-AGNs) identified by Guo et al. (2025), we investigate the evolutionary sequence of broad emission lines using a redshift-selected subset (0.35 < z < 0.45) of 54 CL-AGNs…

Abstract abridged. The eROSITA X-ray telescope aboard the SRG orbital observatory, in the course of its all-sky survey, is expected to detect about three million active galactic nuclei (AGN) and hundred thousand clusters and groups of…

High Energy Astrophysical Phenomena · Physics 2023-01-11 S. D. Bykov , M. R. Gilfanov , R. A. Sunyaev

Off-nucleus active galactic nuclei (AGN) can be signposts of inspiraling supermassive black holes (SMBHs) on galactic scales, or accreting SMBHs recoiling after the coalescence of a SMBH binary or slingshot from three-body interactions.…

Astrophysics of Galaxies · Physics 2021-08-17 Yue Shen , Hsiang-Chih Hwang , Nadia Zakamska , Xin Liu

In this study, a new semi-empirical calibration is proposed between ultraviolet emission lines (\ion{C}{iii}]$\lambda1909$, \ion{C}{iv}$\lambda1549$, \ion{He}{ii}]$\lambda1640$) of type~2 AGNs and their metallicity ($Z$). This calibration…

We estimated the magnetic field strength at the event horizon for a sample of supermassive black holes (SMBHs) in active galactic nuclei (AGNs). Our estimates were made using the values of the inclination angles of the accretion disk to the…

High Energy Astrophysical Phenomena · Physics 2020-05-20 M. Yu. Piotrovich , A. G. Mikhailov , S. D. Buliga , T. M. Natsvlishvili

Active Galactic Nuclei (AGN) play a decisive role in galaxy evolution, particularly so when operating in a radiatively inefficient mode, where they launch powerful jets that reshape their surroundings. However, identifying them is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Enno Middelberg , Adam Deller , Ray Norris , Sotiria Fotopoulou , Mara Salvato , John Morgan , Walter Brisken , Dieter Lutz , Emmanouil Rovilos

It is not yet clear what triggers the activity of active galactic nuclei (AGNs), but galaxy merging has been suspected to be one of the main mechanisms fuelling the activity. Using deep optical images taken at various ground-based…

Astrophysics of Galaxies · Physics 2015-05-04 Jueun Hong , Myungshin Im , Minjin Kim , Luis C. Ho

Active galactic nuclei (AGN) forming in the early universe are thought to be the primary source of hard ionizing photons contributing to the reionization of intergalactic helium. However, the number density and spectral properties of…

The James Webb Space Telescope (JWST) has unveiled numerous massive black holes (BHs) in faint, broad-line active galactic nuclei (AGNs). The discovery highlights the presence of dust-reddened AGN populations, referred to as "little red…

Astrophysics of Galaxies · Physics 2024-09-13 Kohei Inayoshi , Kohei Ichikawa

We present the broad-band Spectral Energy Distributions (SEDs) of the largest available highly (72%) complete spectroscopic sample of mid-infrared (MIR) selected galaxies and AGN at intermediate redshift. The sample contains 203…