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The $\gamma$-ray emission from active galactic nuclei (AGN), including both beamed blazars and misaligned-AGN, dominates the extragalactic $\gamma$-ray point-source population count and flux. While multi-wavelength studies have detected an…

High Energy Astrophysical Phenomena · Physics 2025-09-26 Milena Crnogorčević , Tim Linden , Annika H. G. Peter

We study the link between the X-ray emission in radio-quiet AGNs and the accretion rate on the central Supermassive Black-Hole (SMBH) using a well-defined and statistically complete sample of 70 type1 AGNs extracted from the XMM-Newton…

High Energy Astrophysical Phenomena · Physics 2012-12-27 R. Fanali , A. Caccianiga , P. Severgnini , R. Della Ceca , M. Dotti , E. Marchese , A. Corral

In the last decade, using single epoch (SE) virial based spectroscopic optical observations, it has been possible to measure the black hole (BH) mass on large type 1 Active Galactic Nuclei (AGN) samples. However this kind of measurements…

Over the last 12 years, AGN monitoring by RXTE, has revolutionised our understanding of the X-ray variability of AGN, of the relationship between AGN and Galactic black hole X-ray binaries (BHBs) and hence of the accretion process itself,…

High Energy Astrophysical Phenomena · Physics 2014-11-20 I. M. McHardy

We have selected a sample of 292 SDSS Narrow-Emission-Line galaxies known to have formed and evolved in relative isolation to study the nature and origin of the AGN phenomenon. The galaxies in our sample have line fluxes with S/N>3 and were…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-09 D. M. Neri-Larios , R. Coziol , J. P. Torres-Papaqui , H. Andernach , J. M. Islas-Islas , I. Plauchu-Frayn , R. A. Ortega-Minakata

We report the discovery of a candidate active galactic nucleus (AGN), 2XMM J123103.2+110648 at z = 0.13, with an X-ray spectrum represented purely by soft thermal emission reminiscent of Galactic black hole (BH) binaries in the…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Yuichi Terashima , Naoya Kamizasa , Hisamitsu Awaki , Aya Kubota , Yoshihiro Ueda

We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns including our ongoing campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs). This sample covers…

The standard alpha-disc model predicts an anti-correlation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in higher mass ($M_{\rm BH}>10^{6} M_{\odot}$) active galactic…

A strong X-ray emission is one of the defining signatures of nuclear activity in galaxies. According to the Unified Model for Active Galactic Nuclei (AGN), both the X-ray radiation and the prominent broad emission lines, characterizing the…

Astrophysics of Galaxies · Physics 2015-06-17 G. La Mura , M. Berton , S. Ciroi , V. Cracco , F. Di Mille , P. Rafanelli

The Gigahertz Peaked Spectrum (GPS) sources, Compact Steep Spectrum (CSS) radio sources, and High Frequency Peakers (HFP) radio sources are thought to be young radio AGNs, at the early stage of AGN evolution. We investigated the optical…

Astrophysics of Galaxies · Physics 2019-12-11 Mai Liao , Minfeng Gu

The soft X-ray excess - the excess of X-rays below 2 keV with respect to the extrapolation of the hard X-ray spectral continuum model - is a very common feature among type 1 active galactic nuclei (AGN); yet the nature of the soft X-ray…

High Energy Astrophysical Phenomena · Physics 2020-01-08 M. Gliozzi , J. K. Williams

Several studies of nearby active galactic nuclei (AGN) have shown that the soft X-ray emission presents a size and morphology that resembles that of the narrow-line region (NLR) traced by [O III]. Since the NLR is mainly constituted by gas…

We study the optical variability of a sample of candidate low-mass (dwarf ang Seyfert) active galactic nuclei (AGNs) using Zwicky Transient Facility g-band light curves. Our sample is compiled from broad-line AGNs in dwarf galaxies reported…

Astrophysics of Galaxies · Physics 2023-04-11 Z. Franklin Wang , Colin J. Burke , Xin Liu , Yue Shen

We study a large sample of dwarf galaxies using archival Chandra X-ray observations, with the aim of detecting accreting intermediate-mass black holes (IMBHs). IMBHs are expected to inhabit dwarf galaxies and to produce specific signatures…

High Energy Astrophysical Phenomena · Physics 2022-04-06 Marko Mićić , Jimmy A. Irwin , Dacheng Lin

(Abridged) Using an empirical relation between the broad line region size and optical continuum luminosity, we estimated the black hole mass and accretion rate for 135 AGNs with double-peaked broad emission lines in two samples. With black…

Astrophysics · Physics 2009-11-10 Xue-Bing Wu , F. K. Liu

We investigate the role of host galaxy classification and black hole mass in a heterogeneous sample of 276 mostly nearby (z<0.1) X-ray and IR selected AGN. Around 90% of Seyfert 1 AGN in bulge-dominated host galaxies (without disk…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Barry McKernan , K. E. Saavik Ford , Chris Reynolds

This paper presents a survey of X-ray selected active galactic nuclei (AGN) with optical spectroscopic follow-up in a $\sim 18\, \rm{deg^2}$ area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by…

The scaling relations between the black hole (BH) mass and soft lag properties for both active galactic nuclei (AGNs) and BH X-ray binaries (BHXRBs) suggest the same underlying physical mechanism at work in accreting BH systems spanning a…

We present an analysis of the X-ray emission of a large sample of z~3 Lyman break galaxies (LBGs), based on Chandra/ACIS observations of several LBG survey fields. 24 LBGs are directly detected in the X-ray. 13 of the LBGs have optical…

Astrophysics · Physics 2009-11-11 E. S. Laird , K. Nandra , A. Hobbs , C. C. Steidel

We present a systematic X-ray and multiwavelength study of a sample of 47 active galactic nuclei (AGNs) with reverberation-mapping measurements. This sample includes 21 super-Eddington accreting AGNs and 26 sub-Eddington accreting AGNs.…

Astrophysics of Galaxies · Physics 2021-04-07 Hezhen Liu , B. Luo , W. N. Brandt , Michael S. Brotherton , S. C. Gallagher , Q. Ni , Ohad Shemmer , J. D. Timlin
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