Results 41 to 50 of about 9,238,867 (222)

BASS. XXII. The BASS DR2 AGN Catalog and Data

The Astrophysical Journal Supplement Series, 2022
We present the active galactic nucleus (AGN) catalog and optical spectroscopy for the second data release of the Swift BAT AGN Spectroscopic Survey (BASS DR2).
Michael J. Koss, Claudio Ricci, Benny Trakhtenbrot, Kyuseok Oh, Jakob S. den Brok, Julian E. Mejía-Restrepo, Daniel Stern, George C. Privon, Ezequiel Treister, Meredith C. Powell, Richard Mushotzky, Franz E. Bauer, Tonima T. Ananna, Mislav Baloković, Rudolf E. Bär, George Becker, Patricia Bessiere, Leonard Burtscher, Turgay Caglar, Enrico Congiu, Phil Evans, Fiona Harrison, Marianne Heida, Kohei Ichikawa, Nikita Kamraj, Isabella Lamperti, Fabio Pacucci, Federica Ricci, Rogério Riffel, Alejandra F. Rojas, Kevin Schawinski, Matthew J. Temple, C. Megan Urry, Sylvain Veilleux, Jonathan Williams   +34 more
doaj   +1 more source

Review on Active-Galactic Nuclei at hard X-ray energies [PDF]

Proceedings of An INTEGRAL view of the high-energy sky (the first 10 years) - 9th INTEGRAL Workshop and celebration of the 10th anniversary of the launch — PoS(INTEGRAL 2012), 2013
Hard X-ray surveys are an important tool for the study of active galactic nuclei (AGN): they provide almost an unbiased view of absorption in the extragalactic population, allow the study of spectral features such as reflection and high energy cut-off which would otherwise be unexplored and favour the discovery of some blazars at high redshift.
Bassani, Loredana, Molina, M., Malizia, A., Panessa, F., Landi, R., Bazzano, A., Ubertini, P., Bird, A. J., Stephen, J. B.   +8 more
openaire   +2 more sources

The location and kinematics of the emission line regions in Active Galactic Nuclei [PDF]

, 2008
This thesis contains the results from a study of the optical emission lines of various samples of active galactic nuclei (AGN). We have used three separate techniques to determine the precise kinematics and the relative location of the emission line ...
Mullaney, J R, Mullaney, J.R.
core  

Direct SMBH Formation Driven by Runaway Stellar Collisions in Globally Unstable Stellar Systems

Astronomische Nachrichten, EarlyView.
ABSTRACT The fueling problem addresses the ultimate fate of the reservoirs of gas and stars driven into the deepest gravitational potential wells of galaxies, thus it may contain the Universe's densest concentrations of gas and stars. This raises a key question: does the infalling material collapse directly into a supermassive black hole, or can it ...
Marcelo C. Vergara, Andrés Escala
wiley   +1 more source

Fast X-Ray Variability from the Coronae of Supermassive Black Holes

The Astrophysical Journal Letters
We present the first systematic study of short-timescale X-ray variability in radio-quiet active galactic nuclei (AGN), utilizing archival Chandra observations of approximately 3000 broad-line AGN selected from the Sloan Digital Sky Survey and Dark ...
Xiurui Zhao, Luca Comisso, Stefano Marchesi, Marco Ajello, Elias Kammoun, Yue Shen, Qiaoya Wu   +6 more
doaj   +1 more source

Radiation pressure acceleration by X-rays in active galactic nuclei [PDF]

Monthly Notices of the Royal Astronomical Society, 2001
We present calculations of the dynamics of highly ionized gas clouds that are confined by external pressure, and are ionized by AGN continuum. We focus on the gas that is seen in absorption in the X-ray spectrum of many AGN and show that such gas can reach hydrostatic equilibrium under various conditions. The principal conclusion is that the clouds can
Chelouche, Doron, Netzer, Hagai
openaire   +2 more sources

The properties of discrete X-ray sources in star-forming galaxies [PDF]

, 2012
Observations of starburst galaxies have revealed a large number of point-like X-ray sources located within these systems, including active galactic nuclei (AGN), X-ray binaries (XRBs), and utraluminous X-ray sources (ULXs).
JACKSON, FLOYD,EMMANUEL
core  

Simulations of X-ray bursts and superbursts [PDF]

, 2015
Observations of neutron star in binary systems provide powerful constrains on the physics at the surface of neutron stars. During the accretion of matter from the companion star, periodic nuclear explosion are triggered in the outer layers of the neutron
Fehlmann, Sofie
core   +1 more source

Ultrafast Transitions in X‐Ray Irradiated Solids

Contributions to Plasma Physics, EarlyView.
ABSTRACT In this review, we present current developments on modeling ultrafast transitions in solids triggered by intense, atto‐ to femtosecond pulses from X‐ray free electron lasers. This specific irradiation regime requires dedicated simulation tools based on theoretical and computational methods, involving the elements of classical and quantum ...
Sebastião Antunes, Konrad J. Kapcia, Vladimir Lipp, Beata Ziaja   +3 more
wiley   +1 more source

The Hidden Variability of the Torus in Local Active Galactic Nuclei: 20 yr of Chandra, XMM-Newton, and NuSTAR Observations

The Astrophysical Journal
X-ray absorption variability in active galactic nuclei (AGN) provides key constraints on the structure and dynamics of the circumnuclear obscuring medium, the so-called torus. A fraction of nearby AGN, however, have been classified as nonvariable in line-
Vittoria Elvezia Gianolli, Núria Torres-Albà, Stefano Marchesi, Marco Ajello, Claudio Ricci, Isaiah Cox, Massimo Gaspari, Dhrubojyoti Sengupta, Ross Silver, Indrani Pal, Andrealuna Pizzetti, Xiurui Zhao   +11 more
doaj   +1 more source