Results 101 to 110 of about 117,210 (326)
METALLICITY AND QUASAR OUTFLOWS [PDF]
The Astrophysical Journal, 2012 13 pages, 4 figures, 1 table, accepted for publication in ...
Hongyan Zhou +4 more
openaire +4 more sources
A Unified, Merger-driven Model of the Origin of Starbursts, Quasars, the Cosmic X-Ray Background, Supermassive Black Holes, and Galaxy Spheroids [PDF]
, 2005 We present an evolutionary model for starbursts, quasars, and spheroidal galaxies in which mergers between gas-rich galaxies drive nuclear inflows of gas, producing starbursts and feeding the buried growth of supermassive black holes (BHs) until feedback
P. Hopkins +5 more
semanticscholar +1 more source
Red Type-1 Quasars after Cosmic Noon and Impact on L UV-related Quasar Statistics
The Astrophysical JournalOver the past decades, nearly a million quasars have been explored to shed light on the evolution of supermassive black holes and galaxies. The ultraviolet-to-optical spectra of type-1 quasars particularly offer insights into their black hole activities.
Yongjung Kim +3 more
doaj +1 more source
Exploratory Chandra Observations of the Three Highest Redshift Quasars Known
, 2002 We report on exploratory Chandra observations of the three highest redshift quasars known (z = 5.82, 5.99, and 6.28), all found in the Sloan Digital Sky Survey.
Bing Chen +16 more
core +1 more source
An Empirical Calibration of the Completeness of the SDSS Quasar Survey [PDF]
, 2005 Spectra of nearly 20000 point-like objects to a Galactic reddening corrected magnitude of i=19.1 have been obtained to test the completeness of the SDSS quasar survey.
Avery Meiksin +14 more
core +2 more sources
Astronomische Nachrichten, EarlyView.ABSTRACT Classification of galaxies, stars, and quasars using spectral data is fundamental to astronomy, but often relies heavily on redshift. This study evaluates the performance of 10 machine learning algorithms on SDSS data to classify these objects, with a particular focus on scenarios where redshift information is unavailable.
Debashis Chatterjee, Prithwish Ghosh
wiley +1 more source
The Jets in Micro-Quasars and Quasars: A Comparison [PDF]
Highlights of Astronomy, 2005 AbstractThe discovery of relativistic jets in radio emitting X-ray binaries in our own galaxy has led to the term ‘microquasar’ being coined for these objects. In this paper the properties of microquasars are compared with those of quasars and radio galaxies, with the aim of trying to see how the similarities and differences can inform us about the ...
openaire +1 more source
Quasars Probing Quasars. IX. The Kinematics of the Circumgalactic Medium Surrounding z ∼ 2 Quasars [PDF]
The Astrophysical Journal, 2018 Abstract We examine the kinematics of the gas in the environments of galaxies hosting quasars at z ∼ 2. We employ 148 projected quasar pairs to study the circumgalactic gas of the foreground quasars in absorption. The sample selects foreground quasars with precise redshift measurements, using emission lines with precision ≲300 km s−1 and
Marie Wingyee Lau +2 more
openaire +4 more sources
A new physical interpretation of optical and infrared variability in quasars [PDF]
Monthly notices of the Royal Astronomical Society, 2018 Changing-look quasars are a recently identified class of active galaxies in which the strong UV continuum and/or broad optical hydrogen emission lines associated with unobscured quasars either appear or disappear on time-scales of months to years.
N. Ross +13 more
semanticscholar +1 more source
The X-ray Properties of z>4 Quasars [PDF]
, 2000 We report on a search for X-ray emission from quasars with redshifts greater than four using the ROSAT public database. Our search has doubled the number of z>4 quasars detected in X-rays from 6 to 12.
Blair A. J. +13 more
core +2 more sources