Results 91 to 100 of about 10,418 (177)
Evidence of Gas Depletion in Quasars with Moderate Radio Emission
The Astrophysical JournalThe energy released by active galactic nuclei (AGNs) is considered to have a profound impact on the cold gas properties of their host galaxies, potentially heating or removing the gas and further suppressing star formation.
Yuhan Wen +6 more
doaj +1 more source
Probing the Heart of Active Narrow-line Seyfert 1 Galaxies with VERA Wideband Polarimetry
The Astrophysical Journal, 2023 We explored the parsec-scale nuclear regions of a sample of radio-loud narrow-line Seyfert 1 galaxies (NLSy1s) using the VLBI Exploration of Radio Astrometry wideband (at a recording rate of 16 Gbps) polarimetry at 22 and 43 GHz.
Mieko Takamura +11 more
doaj +1 more source
The Astrophysical JournalNarrow-line Seyfert 1 galaxies (NLS1s) are generally known to be radio-quiet active galactic nuclei, but a tiny subset of them are found to be extremely radio-loud with radio loudness parameter ( R _1.4 GHz ) > 100.
Veeresh Singh +3 more
doaj +1 more source
The X-ray Properties of the Most-Luminous Quasars from the Sloan Digital Sky Survey
, 2007 Utilizing 21 new Chandra observations as well as archival Chandra, ROSAT, and XMM-Newton data, we study the X-ray properties of a representative sample of 59 of the most optically luminous quasars in the Universe (M_i~~-29.3 to -30.2) spanning a redshift
Brandt, W. N. +6 more
core +2 more sources
Resolving the Powerful Radio-loud Quasar at z ∼ 6 [PDF]
The Astrophysical Journal, 2018 We present high angular resolution imaging ($23.9 \times 11.3$ mas, $138.6 \times 65.5$ pc) of the radio-loud quasar PSO~J352.4034$-$15.3373 at $z=5.84$ with the Very Long Baseline Array (VLBA) at 1.54 GHz. This quasar has the highest radio-to-optical flux density ratio at such a redshift, making it the radio-loudest source known to date at $z \sim 6$.
Emmanuel Momjian +4 more
openaire +3 more sources
Probing the Low-radio-frequency Emission in PG Quasars with the uGMRT. II
The Astrophysical Journal Supplement SeriesWe present results from uGMRT 685 MHz observations of 87 QSOs belonging to the Palomar–Green (PG) quasar sample with z
Sanna Gulati +5 more
doaj +1 more source
The relationship between the emission line, continuum luminosity, and Baldwin effect in blazars
Astronomy & AstrophysicsAims. This study investigates the relationship between the Mg II λ2798 Å emission line and the 3000 Å continuum luminosity, as well as the Baldwin effect, in a sample of 40’,685 radio-quiet (RQ) quasars and 441 flat spectrum radio quasars (FSRQs ...
Patiño-Álvarez Víctor M. +5 more
doaj +1 more source
The Jet-Disk Coupling of Seyfert Galaxies from a Complete Hard X-ray Sample
Universe, 2020 We analyze the jet-disk coupling for different subsamples from a complete hard X-ray Seyfert sample to study the coupling indices and their relation to accretion rate.
Xiang Liu +3 more
doaj +1 more source
The correlations between optical variability and physical parameters of quasars in SDSS Stripe 82
, 2012 We investigate the optical variability of 7658 quasars from SDSS Stripe 82. Taking advantage of a larger sample and relatively more data points for each quasar, we estimate variability amplitudes and divide the sample into small bins of redshift, rest ...
Ai +40 more
core +1 more source
IRAS observations of radio-quiet and radio-loud quasars
The Astrophysical Journal, 1984 Observations from 12 to 100 microns are presented of two radio-quiet and three radio-loud quasars. Over this wavelength range, all five have grossly similar continuum energy distributions. The continua of the radio-loud quasars are consistent with synchrotron radiation.
Neugebauer, G. +9 more
openaire +3 more sources