Results 41 to 50 of about 62,437 (252)

NGC 5252: a pair of radio-emitting active galactic nuclei? [PDF]

, 2016
The X-ray source CXO J133815.6+043255 has counterparts in the UV, optical, and radio bands. Based on the multiband investigations, it has been recently proposed by Kim et al. as a rarely seen off-nucleus ultraluminous X-ray (ULX) source with a black hole
Xiaolong Yang, Jun Yang, Z. Paragi, Xiang Liu, T. An, S. Bianchi, L. Ho, L. Cui, Wei Zhao, Xiaocong Wu   +9 more
semanticscholar   +1 more source

The Role of Active Galactic Nuclei in the Quenching of Massive Galaxies in the SQuIGG E Survey [PDF]

Astrophysical Journal, 2020
We study the incidence of nuclear activity in a large sample of massive post-starburst (PSB) galaxies at selected from the Sloan Digital Sky Survey, and identify active galactic nuclei based on radio continuum and optical emission lines.
J. Greene, D. Setton, R. Bezanson, K. Suess, M. Kriek, J. Spilker, A. Goulding, R. Feldmann   +7 more
semanticscholar   +1 more source

Testing the Linear Relationship between Black Hole Mass and Variability Timescale in Low-luminosity AGNs at Submillimeter Wavelengths

The Astrophysical Journal, 2023
The variability of submillimeter emission provides a useful tool to probe the accretion physics in low-luminosity active galactic nuclei. We accumulate four years of observations using the Submillimeter Array for Centaurus A, NGC 4374, NGC 4278, and NGC ...
Bo-Yan Chen, Geoffrey C. Bower, Jason Dexter, Sera Markoff, Anthony Ridenour, Mark A. Gurwell, Ramprasad Rao, Sofia H. J. Wallström   +7 more
doaj   +1 more source

Detecting the 21 cm Forest in the 21 cm Power Spectrum

, 2014
We describe a new technique for constraining the radio loud population of active galactic nuclei at high redshift by measuring the imprint of 21 cm spectral absorption features (the 21 cm forest) on the 21 cm power spectrum.
Dillon, Joshua S., Ewall-Wice, Aaron, Hewitt, Jacqueline, Mesinger, Andrei   +3 more
core   +1 more source

Searching for Quasiperiodic Modulations in γ-Ray Active Galactic Nuclei [PDF]

Astrophysical Journal, 2020
We perform a systematic search of quasiperiodic variabilities in γ-ray active galactic nuclei in the third Fermi Large Area Telescope source catalog (3FGL).
Peng-fei Zhang, D. Yan, Jia-Neng Zhou, Jian-cheng Wang, Li Zhang   +4 more
semanticscholar   +1 more source

Overview and Status of the International Celestial Reference Frame as Realized by VLBI

Universe, 2022
Accurate measurement of angular positions on the sky requires a well-defined system of reference that is realized with accessible objects. The purpose of this study is to review the international standard realization of such a system, the International ...
Aletha de Witt, Patrick Charlot, David Gordon, Christopher S. Jacobs   +3 more
doaj   +1 more source

The Correlation between X-ray spectral slope and FeKalpha line energy in radio-quiet active galactic nuclei

, 2002
A significant correlation between FeKalpha line energy and X-ray spectral slope has been discovered among radio-quiet active galactic nuclei. The ionization stage of the bulk of the FeKalpha emitting material is not the same in all active galactic nuclei
Arnaud K. A., Boller T., Brandt W. N., Fabian A. C., George I. M., Grupe D., Guainazzi M., Guilbert P. W., Gulab Chand Dewangan, Koenig M., Mineo T., Pounds K. A., Reynolds C. S., Winkler H., Wisotzki L.   +14 more
core   +1 more source

Origin of Radio Emission from Nearby Low-Luminosity Active Galactic Nuclei

, 2004
We use the observational data in radio, optical and X-ray wavebands, for a sample of active galactic nuclei (AGNs) with measured black hole masses, to explore the origin of radio emission from nearby low-luminosity active galactic nuclei (LLAGNs).
Falcke H., Ishisaki Y., Qingwen Wu, Schulz H., Stanger V. J., Trinchieri G., Turner T. J., Witt H. J., Xinwu Cao   +8 more
core   +1 more source

The many lives of active galactic nuclei: cooling flows, black holes and the luminosities and colour [PDF]

, 2005
We simulate the growth of galaxies and their central supermassive black holes by implementing a suite of semi-analytic models on the output of the Millennium Run, a very large simulation of the concordance A cold dark matter cosmogony.
D. Croton, V. Springel, S. White, G. Lucia, C. Frenk, Liang Gao, A. Jenkins, G. Kauffmann, J. Navarro, N. Yoshida   +9 more
semanticscholar   +1 more source

The TANAMI Program [PDF]

, 2009
TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) is a monitoring program to study the parsec-scale structures and dynamics of relativistic jets in active galactic nuclei (AGN) of the Southern Hemisphere with the Long ...
Boeck, M., Booth, R., Dutka, M. S., Edwardsk, P., Fey, A. L., Fuhrmann, L., Hase, H., Horiuchi, S., Jauncey, D. L., Johnston, K. J., Kadler, Matthias, Katz, U., Lister, M., Lovell, J. E. J., Mueller, Cornelia, Ojha, Roopesh, Ploetz, C., Quick, J. F. H., Ros, E., Taylor, G. B., Thompson, D. J., Tingay, S. J., Tosti, G., Tzioumisk, A. K., Wilms, J., Zensus, J. A.   +25 more
core   +2 more sources