Results 21 to 30 of about 183 (149)
3C 57 as an atypical radio-loud quasar: implications for the radio-loud/radio-quiet dichotomy [PDF]
Monthly Notices of the Royal Astronomical Society, 2015 Accepted for publication in MNRAS; 10 pages, 6 figures, 4 ...
Sulentic, J. W. +6 more
openaire +5 more sources
CONSTRAINING THE RADIO-LOUD FRACTION OF QUASARS ATz> 5.5 [PDF]
The Astrophysical Journal, 2015 Radio-loud Active Galactic Nuclei at z~2-4 are typically located in dense environments and their host galaxies are among the most massive systems at those redshifts, providing key insights for galaxy evolution. Finding radio-loud quasars at the highest accessible redshifts (z~6) is important to study their properties and environments at even earlier ...
E. Bañados +20 more
openaire +5 more sources
Spectral Variability in Radio-Loud Quasars [PDF]
Journal of Astrophysics and Astronomy, 2014 5 pages, 3 figures, accepted to JApA, conference proceeding paper for Variability of Blazars - From Jansky to Fermi (VBJF), Dec.
openaire +2 more sources
The optical variability of radio-loud quasars [PDF]
Proceedings of the International Astronomical Union, 2012 AbstractThe optical variability of a sample of 44 FSRQs and 18 SSRQs in the SDSS stripe 82 region is investigated by using the multi-epoch data covering nine years. The variabilities are clearly detected in each source with the amplitude in r band, from 0.18 to 3.46 mag.
Minfeng Gu, Y. L. Ai
openaire +1 more source
Spectroscopic properties of radio-loud and radio-quiet quasars [PDF]
Proceedings of the International Astronomical Union, 2019 AbstractSurveys have shown radio-loud (RL) quasars constitute 10%-15% of the total quasar population and rest are radio-quiet (RQ). However, it is unknown if this radio-loud fraction (RLF) remains consistent among different parameter spaces. This study shows that RLF increases for increasing full width half maximum (FWHM) velocity of the Hβ broad ...
Chakraborty, Avinanda +1 more
openaire +4 more sources
Astrometric Apparent Motion of High-redshift Radio Sources
The Astronomical Journal, 2023 Radio-loud quasars at high redshift ( z ≥ 4) are rare objects in the universe and rarely observed with Very Long Baseline Interferometry (VLBI). But some of them have flux density sufficiently high for monitoring of their apparent position.
Oleg Titov +12 more
doaj +1 more source
Retrograde versus Prograde Models of Accreting Black Holes
Advances in Astronomy, Volume 2013, Issue 1, 2013., 2013 There is a general consensus that magnetic fields, accretion disks, and rotating black holes are instrumental in the generation of the most powerful sources of energy in the known universe. Nonetheless, because magnetized accretion onto rotating black holes involves both the complications of nonlinear magnetohydrodynamics that currently cannot fully be
David Garofalo, Alberto J. Castro-Tirado
wiley +1 more source
The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Significant progress has been made in the last few years on understanding how supermassive black holes form and grow. In this paper, we begin by reviewing the spectral signatures of active galactic nuclei (AGN) ranging from radio to hard X‐ray wavelengths.
Ezequiel Treister +2 more
wiley +1 more source
A Practical Guide to the Massive Black Hole Cosmic History
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 I review our current understanding of massive black hole (MBH) formation and evolution along the cosmic history. After a brief introductory overview of the relevance of MBHs in the hierarchical structure formation paradigm, I discuss the main viable channels for seed BH formation at high redshift and for their subsequent mass growth and spin evolution.
A. Sesana, Francesco Shankar
wiley +1 more source
Evidence for AGN Feedback in Galaxy Clusters and Groups
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 The current generation of flagship X‐ray missions, Chandra and XMM-Newton, has changed our understanding of the so‐called “cool‐core” galaxy clusters and groups. Instead of the initial idea that the thermal gas is cooling and flowing toward the center, the new picture envisages a complex dynamical evolution of the intracluster medium (ICM) regulated by
Myriam Gitti +3 more
wiley +1 more source