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We combine the Herschel Space Observatory PACS and SPIRE photometry with archival WISE photometry to construct the spectral energy distributions (SED) for over 300 local ($z < 0.05$), ultra-hard X-ray (14 - 195 keV) selected active galactic…

Astrophysics of Galaxies · Physics 2017-02-01 T. Taro Shimizu , Richard F. Mushotzky , Marcio Meléndez , Michael J. Koss , Amy J. Barger , Lennox L. Cowie

In this paper we study the properties of the optical spectra of Type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. We develop the `Correlation Spectrum Technique' (CST) and use this to show the…

High Energy Astrophysical Phenomena · Physics 2015-06-04 C. Jin , M. Ward , C. Done

Accretion plays an important role in protoplanetary disk evolution, and it is thought that the accretion mechanism changes between low- and high-mass stars. Here, we characterize accretion in intermediate-mass, pre-main-sequence Herbig…

Solar and Stellar Astrophysics · Physics 2022-03-09 Sierra L. Grant , Catherine C. Espaillat , Sean Brittain , Caleb Scott-Joseph , Nuria Calvet

Active galactic nuclei (AGN) emit radiation over a wide range of wavelengths, with a peak of emission in the far-UV region of the electromagnetic spectrum, a spectral region that is historically difficult to observe. Using optical, GALEX UV…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 E. Marchese , R. Della Ceca , A. Caccianiga , P. Severgnini , A. Corral , R. Fanali

Active galactic nuclei (AGNs) show a correlation between the size of the broad line region (BLR) and the monochromatic continuum luminosity at 5100 \AA, allowing black hole mass estimation based on single-epoch spectra. However, the…

The structure of the accretion disk in AGN is still an unsolved question, especially how it may change with Eddington ratio. Here we examine the accretion disk in the super-Eddington AGN I Zw 1 using reverberation mapping of the optical…

Two effects have substantially increased the scatter in the AGN black hole mass - host galaxy bulge luminosity relationship derived from SDSS spectra. The first is that at a fixed black hole mass, the SDSS spectrum depends strongly on…

Astrophysics of Galaxies · Physics 2009-07-13 C. Martin Gaskell , John Kormendy

We present line and continuum measurements for 9818 SDSS type-I active galactic nuclei (AGNs) with z le 0.75. The data are used to study the four dimensional space of black hole mass, normalized accretion rate (Ledd), metalicity and…

Astrophysics · Physics 2008-11-26 Hagai Netzer , Benny Trakhtenbrot

In the past few years more and more pieces of evidence have been presented for a revision of the widely accepted Unified Model of Active Galactic Nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Andrea Marinucci , Stefano Bianchi , Fabrizio Nicastro , Giorgio Matt , Andy D. Goulding

We investigate the relationship between black hole accretion and star formation in a sample of 453 $z\approx0.3$ type 1 active galactic nuclei (AGNs). We use available CO observations to demonstrate that the combination of nebular dust…

Astrophysics of Galaxies · Physics 2021-01-13 Ming-Yang Zhuang , Luis C. Ho , Jinyi Shangguan

We measure the bolometric luminosity of a complete and unbiased 12 micron-selected sample of active galactic nuclei (AGN) in the local Universe. For each galaxy we used a 10-band radio-to-X-ray Spectral Energy Distribution (SED) to isolate…

Astrophysics of Galaxies · Physics 2023-12-22 Luigi Spinoglio , Juan Antonio Fernandez-Ontiveros , Matthew A. Malkan

In this research, we provide a new, efficient method to select infrared (IR) active galatic nucleus (AGN). In the past, AGN selection in IR had been established by many studies using color-color diagrams. However, those methods have a…

Astrophysics of Galaxies · Physics 2017-12-07 Ting-Chi Huang , Tomotsugu Goto , Tetsuya Hashimoto , Nagisa Oi , Hideo Matsuhara

AGN, powered by accretion onto SMBHs, are thought to be scaled up versions of Galactic black hole X-ray binaries (BH-XRBs). In the past few years evidence of such correspondence include similarities in the broadband shape of the X-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-05 O. Gonzalez-Martin , S. Vaughan

We present evidence that the incidence of active galactic nuclei (AGNs) and the distribution of their accretion rates do not depend on the stellar masses of their host galaxies, contrary to previous studies. We use hard (2-10 keV) X-ray…

We have constructed a grid of non-LTE disk models for a wide range of black hole mass and mass accretion rate, for several values of viscosity parameter alpha, and for two extreme values of the black hole spin: the maximum-rotation Kerr…

Astrophysics · Physics 2009-10-31 Ivan Hubeny , Eric Agol , Omer Blaes , Julian Krolik

Low-luminosity AGNs are perceived to be radio loud and devoid of a ``big blue bump'', indicating a transition from a radiatively efficient, geometrically thin, accretion disc in high-luminosity AGNs, to a geometrically thick, radiatively…

Astrophysics · Physics 2008-11-26 Dan Maoz

We present one of the largest multiwavelength studies of simultaneous optical-to-X-ray spectral energy distributions (SEDs) of unobscured active galactic nuclei (AGN) in the local Universe. Using a representative sample of…

It is well known that supermassive black holes (SMBHs) and their host galaxies co-evolve. AGN feedback plays an important role on this symbiosis. To study the effect of the AGN feedback on the host galaxy, a popular method is to study the…

Astrophysics of Galaxies · Physics 2023-12-06 George Mountrichas , Veronique Buat

The structure of accretion flows in low-luminosity active galactic nuclei (AGN) at low Eddington ratios (~10^-2 to 10^-3) are poorly-understood, and can be probed using the spectral energy distributions (SEDs) of faded changing-look (CL)…

The bolometric luminosity of active galactic nuclei (AGN) is difficult to determine and various approximations have been used to calibrate it against different observed properties. Here I combine theoretical calculations of optically thick,…

Astrophysics of Galaxies · Physics 2019-07-31 Hagai Netzer