Results 81 to 90 of about 166 (155)

Radio Scrutiny of the X-Ray-weak Tail of Low-mass Active Galactic Nuclei: A Novel Signature of High-Eddington Accretion?

The Astrophysical Journal
The supermassive black holes ( M _BH ∼ 10 ^6 –10 ^10 M _⊙ ) that power luminous active galactic nuclei (AGNs), i.e., quasars, generally show a correlation between thermal disk emission in the ultraviolet (UV) and coronal emission in hard X-rays.
Jeremiah D. Paul, Richard M. Plotkin, W. N. Brandt, Christopher H. Ellis, Elena Gallo, Jenny E. Greene, Luis C. Ho, Amy E. Kimball, Daryl Haggard   +8 more
doaj   +1 more source

Radio imaging of gravitationally lensed radio-quiet quasars

Monthly Notices of the Royal Astronomical Society
ABSTRACT We present 6 GHz Very Large Array radio images of 70 gravitational lens systems at 300 mas resolution, in which the source is an optically selected quasar, and nearly all of which have two lensed images. We find that about in half of the systems (40/70, with 33/70 secure), one or more lensed images are detected down to our ...
Neal Jackson, Shruti Badole, Thomas Dugdale, Hannah R Stacey, Philippa Hartley, J P McKean   +5 more
openaire   +5 more sources

Radio Follow-up Observations of a Weak-line Quasar Exhibiting Remarkable X-Ray Variability

The Astrophysical Journal
SDSS J1539+3954 ( z  ≈ 1.935), a radio-quiet weak-line quasar (WLQ), exhibited exceptional X-ray variability in 2019–2020, with its X-ray flux increasing by over 20 times from 2013 to 2019 and subsequently dropping by at least a factor of 9 in 2020 ...
Ayushi Chhipa, M. Vivek, Nayana A. J., P. Kharb, W. N. Brandt, Preshanth Jagannathan, Janhavi Baghel, Savithri H. Ezhikode, C. H. Ishwara-Chandra   +8 more
doaj   +1 more source

Do All the Quasars and High-excitation Radio Galaxies (HERGs) in the 3CRR Catalog Contain a Magnetically Arrested Disk (MAD)?

The Astrophysical Journal
Based on the magnetization, an accretion disk with a large-scale magnetic field can be separated into either standard and normal evolution or magnetically arrested disk (MAD), which are difficult to identify from observations. It is still unclear whether
Shuang-Liang Li, Wenwen Zuo, Xinwu Cao
doaj   +1 more source

UEG Week 2025 Oral Presentations

United European Gastroenterology Journal, Volume 13, Issue S8, Page S7-S188, October 2025.
wiley   +1 more source

A Dichotomy in the 1–24 GHz Parsec-scale Radio Spectra of Radio-quiet Quasars

The Astrophysical Journal
We present the parsec-scale radio spectra of a representative sample of 13 Palomar–Green radio-quiet quasars, based on our new Very Long Baseline Array (VLBA) observations at 8.4 and 23.6 GHz and our earlier VLBA studies at 1.5 and 5.0 GHz.
Sina Chen, Ari Laor, Ehud Behar, Ranieri D. Baldi, Joseph D. Gelfand, Amy E. Kimball   +5 more
doaj   +1 more source

The X-ray properties of the most luminous quasars with strong emission-line outflows

Astronomy & Astrophysics
Context. Strong outflows from active galactic nuclei are frequently observed in objects with lower coronal X-ray luminosity. This intrinsic X-ray weakness is considered a requirement for the formation of radiatively driven winds. Aims.
Shlentsova Anastasia, Trefoloni Bartolomeo, Signorini Matilde, Risaliti Guido, Lusso Elisabeta, Nardini Emanuele, Bauer Franz E., Temple Matthew J., Rankine Amy L., Richards Gordon T.   +9 more
doaj   +1 more source

Soft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos. [PDF]

Nat Commun, 2021
Kimura SS, Murase K, Mészáros P.
europepmc   +1 more source

UEG Week 2025 Moderated Posters

United European Gastroenterology Journal, Volume 13, Issue S8, Page S189-S802, October 2025.
wiley   +1 more source

JWST Q3D Program: Active Galactic Nucleus Photoionization and Shock Ionization in a Red Quasar at z = 0.4

The Astrophysical Journal
Red quasars, often associated with potent [O iii ] outflows on both galactic and circumgalactic scales, may play a pivotal role in galactic evolution and black hole feedback. In this work, we explore the [Fe ii ] emission in one such quasar at z = 0.4352–
Swetha Sankar, Nadia L. Zakamska, David S. N. Rupke, Weizhe Liu, Dominika Wylezalek, Sylvain Veilleux, Caroline Bertemes, Nadiia Diachenko, Yu-Ching Chen, Yuzo Ishikawa, Andrey Vayner, Nicole P. H. Nesvadba, Guilin Liu, Andy D. Goulding, Dieter Lutz   +14 more
doaj   +1 more source