Results 111 to 120 of about 512 (214)
The Influence of Microlensing on Time Delay Determinations in Double‐imaged Quasars
The Astrophysical Journal, 1998 The lag associated with the main peak of the cross-correlation function of the two light curves arriving from a double-imaged quasar is usually identified with the time delay between the components. However, short-timescale microlensing events can independently modify the light curve of each component, and when strong microlensing is present, the ...
Luis Julian Goicoechea +4 more
openaire +1 more source
The Astrophysical JournalKiloparsec-scale dual and offset active galactic nuclei (AGNs) are signposts of accreting supermassive black holes (SMBHs) triggered during late-stage galaxy mergers, offering crucial insights into the coevolution of SMBHs and galaxies. However, robustly
Junyao Li +5 more
doaj +1 more source
The Gamma-Ray Luminosity Function of Flat-spectrum Radio Quasars
The Astrophysical JournalWe have utilized the largest sample of gamma-ray-selected Fermi flat-spectrum radio quasars (FSRQs) ever used (519 sources) to construct the luminosity function and its evolution through cosmic history. In addition to spanning large redshift (0
Garima Rajguru +4 more
doaj +1 more source
The Role of Galaxies and Quasars in Reionising the High Redshift Intergalactic Medium [PDF]
, 2020 Only one billion years after the Big Bang, the neutral hydrogen in the intergalactic medium had been completely ionised. This last phase transition of the Universe known as the epoch of reionisation is one of the frontiers in astrophysics.
Meyer, Romain A.
core
The Astrophysical JournalWe present a refined estimation of the stochastic gravitational-wave background (SGWB) based on observed dual active galactic nuclei (AGNs) together with AGN X-ray luminosity functions, in light of recent Pulsar Timing Array (PTA) detections of an nHz ...
Katsunori Kusakabe +2 more
doaj +1 more source
The Astrophysical JournalDual quasars—two active supermassive black holes at galactic scales—represent crucial objects for studying the impact of galaxy mergers and quasar activity on the star formation rate (SFR) within their host galaxies, particularly at cosmic noon when SFR ...
Yu-Ching Chen +14 more
doaj +1 more source
Discovery of 19 strongly lensed, dual, or projected quasars in DESI-LS
We report the results of a follow-up spectroscopic confirmation of two lensed quasars, six dual quasars, and eleven projected quasars that had previously been identified as lensed-quasar candidates in our earlier work.
Nan Li +7 more
core +1 more source
The Astrophysical JournalThe search for dual supermassive black holes (SMBHs) is of immense interest in modern astrophysics. Galaxy mergers may fuel and produce SMBH pairs. Actively accreting SMBH pairs are observed as dual quasars, which are vital probes of SMBH growth.
Yuzo Ishikawa +12 more
doaj +1 more source
Quasars vs. Microquasars: Scaling and Particle Acceleration
Quasars and microquasars both contain accreting black holes and power nonthermal radio sources but differ in more than their scales: Quasars are proportionally much more efficient accelerators of energetic electrons.
Katz, J. I.
core
High-resolution images of five radio quasars at early cosmological epochs
, 2010 Context. Until now, there have only been seven quasars at z > 4.5 whose the high-resolution radio structure had been studied in detail with Very Long Baseline Interferometry (VLBI) imaging. Aims.
L. I. Gurvits +4 more
core +1 more source