Results 51 to 60 of about 238,671 (290)

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

Astrophys.J. 581 (2002) L71-L76, 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 and is related to the shape of the X-ray continua.
arxiv   +1 more source

Little Red Dots: An Abundant Population of Faint Active Galactic Nuclei at z ∼ 5 Revealed by the EIGER and FRESCO JWST Surveys

Astrophysical Journal
Characterizing the prevalence and properties of faint active galactic nuclei (AGNs) in the early Universe is key for understanding the formation of supermassive black holes (SMBHs) and determining their role in cosmic reionization.
J. Matthee, R. Naidu, G. Brammer, J. Chisholm, A. Eilers, A. Goulding, J. Greene, D. Kashino, I. Labbé, S. Lilly, R. Mackenzie, P. Oesch, A. Weibel, S. Wuyts, M. Xiao, R. Bordoloi, R. Bouwens, P. V. van Dokkum, G. Illingworth, I. Kramarenko, M. Maseda, C. Mason, R. Meyer, E. Nelson, N. Reddy, I. Shivaei, R. Simcoe, M. Yue   +27 more
semanticscholar   +1 more source

Quiescent and active galactic nuclei as factories of merging compact objects in the era of gravitational-wave astronomy [PDF]

, 2023
Galactic nuclei harbouring a central supermassive black hole (SMBH), possibly surrounded by a dense nuclear cluster (NC), represent extreme environments which house a complex interplay of many physical processes that uniquely affect stellar formation, evolution, and dynamics. The discovery of gravitational waves (GW) emitted by merging black holes (BHs)
arxiv   +1 more source

UNCOVER Spectroscopy Confirms the Surprising Ubiquity of Active Galactic Nuclei in Red Sources at z > 5

Astrophysical Journal
The James Webb Space Telescope is revealing a new population of dust-reddened broad-line active galactic nuclei (AGN) at redshifts z ≳ 5. Here we present deep NIRSpec/Prism spectroscopy from the Cycle 1 Treasury program Ultradeep NIRSpec and NIRCam ...
J. Greene, I. Labbé, A. Goulding, L. Furtak, Iryna Chemerynska, V. Kokorev, P. Dayal, M. Volonteri, C. Williams, B. Wang 王, David J. Setton, A. Burgasser, R. Bezanson, H. Atek, G. Brammer, Sam E. Cutler, Robert Feldmann, S. Fujimoto, K. Glazebrook, Anna de Graaff, G. Khullar, J. Leja, D. Marchesini, M. Maseda, J. Matthee, T. Miller, R. Naidu, T. Nanayakkara, P. Oesch, R. Pan, C. Papovich, S. Price, P. V. van Dokkum, J. Weaver, K. Whitaker, A. Zitrin   +35 more
semanticscholar   +1 more source

Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database [PDF]

, 2004
We present improved black hole masses for 35 active galactic nuclei (AGNs) based on a complete and consistent reanalysis of broad emission-line reverberation-mapping data.
B. Peterson, L. Ferrarese, K. Gilbert, K. Gilbert, S. Kaspi, S. Kaspi, M. Malkan, D. Maoz, D. Merritt, H. Netzer, C. Onken, R. Pogge, M. Vestergaard, A. Wandel   +13 more
semanticscholar   +1 more source

MOJAVE: MONITORING OF JETS IN ACTIVE GALACTIC NUCLEI WITH VLBA EXPERIMENTS. XI. SPECTRAL DISTRIBUTIONS [PDF]

, 2014
We have obtained milliarcsecond-scale spectral index distributions for a sample of 190 extragalactic radio jets through the Monitoring of Jets in Active Galactic Nuclei with the VLBA Experiments (MOJAVE) project. The sources were observed in 2006 at 8.1,
T. Hovatta, M. Aller, H. Aller, E. Clausen-Brown, D. Homan, Y. Kovalev, M. Lister, A. Pushkarev, T. Savolainen   +8 more
semanticscholar   +1 more source

Tidal Disruption Events in Active Galactic Nuclei [PDF]

Astrophysical Journal, 2019
A fraction of tidal disruption events (TDEs) occur in active galactic nuclei (AGNs) whose black holes possess accretion disks; these TDEs can be confused with common AGN flares.
C. Chan, T. Piran, J. Krolik, Dekel Saban   +3 more
semanticscholar   +1 more source

On the Jet Properties of γ-Ray-loud Active Galactic Nuclei [PDF]

, 2018
Based on broadband spectral energy distributions (SEDs), we estimate the jet physical parameters of 1392 γ-ray-loud active galactic nuclei (AGNs), the largest sample so far. The (SED) jet power and magnetization parameter are derived for these AGNs.
L. Chen
semanticscholar   +1 more source

Mid-infrared Properties of Narrow-line Seyfert 1 Galaxies Detected by LoTSS DR2

The Astrophysical Journal
Narrow-line Seyfert 1 galaxies (NLS1s), a subclass of active galactic nuclei (AGNs) in an early stage of the accretion process, are also found to host relativistic jets. However, currently known jetted NLS1s are rare. The majority of NLS1s are undetected
Xu-Liang Fan
doaj   +1 more source

VARIABILITY OF ACTIVE GALACTIC NUCLEI [PDF]

, 2001
Continuum and emission-line variability of active galactic nuclei provides a powerful probe of microarcsecond scale structures in the central regions of these sources. In this contribution, we review basic concepts and methodologies used in analyzing AGN variability.
openaire   +4 more sources