Results 111 to 120 of about 111,891 (295)
A Deep Chandra X-Ray Survey of a Luminous Quasar Sample at z ∼ 7
The Astrophysical JournalWe present new Chandra observations of seven luminous quasars at z > 6.5. Combined with archival Chandra observations of all other known quasars, they form nearly complete X-ray observations of all currently known z ∼ 7 quasars with M _1450 < –26.5 ...
Xiangyu Jin +13 more
doaj +1 more source
, 2000 We present an empirical investigation of the colors of quasars in the Sloan Digital Sky Survey (SDSS) photometric system. The sample studied includes 2625 quasars with SDSS photometry.
A. J. Connolly +70 more
core +1 more source
THE PAN-STARRS1 DISTANT z > 5.6 QUASAR SURVEY: MORE THAN 100 QUASARS WITHIN THE FIRST GYR OF THE UNIVERSE [PDF]
, 2016 Luminous quasars at can be studied in detail with the current generation of telescopes and provide us with unique information on the first gigayear of the universe. Thus far, these studies have been statistically limited by the number of quasars known at
E. Bañados +40 more
semanticscholar +1 more source
A Main Sequence for Quasars [PDF]
Frontiers in Astronomy and Space Sciences, 2018 The last 25 years saw a major step forward in the analysis of optical and UV spectroscopic data of large quasar samples. Multivariate statistical approaches have led to the definition of systematic trends in observational properties that are the basis of
P. Marziani +9 more
semanticscholar +1 more source
Business Strategy and the Environment, Volume 35, Issue 1, Page 593-614, January 2026.ABSTRACT The circular economy is an approach to decouple economic growth from environmental impacts. In Europe, its development is driven by policies that guide market dynamics through regulations and by businesses innovating with new circular models.
Roger Nyffenegger +3 more
wiley +1 more source
The Study of the Circumgalactic Medium with Quasar Pairs
The Astrophysical Journal Supplement Series, 2023 We have collected 10,025 foreground–background quasar pairs with projected distances d _p < 500 kpc from the large quasar catalog of the Sloan Digital Sky Survey DR16Q. We investigate the properties of the Mg ii absorption lines with W _r > 0.15 Å around
Zhi-Fu Chen +7 more
doaj +1 more source
New Astronomy Reviews, 2006 8 pages, 6 figures, review article with C. Impey at the conference on "QSO Host Galaxies: Evolution and Environment", Aug. 29-Sep.
Peng, Chien Y. +7 more
openaire +2 more sources
Quasar Clustering and the Lifetime of Quasars [PDF]
The Astrophysical Journal, 2001 ApJ Accepted (Feb 2001). 30 pages, 8 embedded ps figures, AASTEX5. Added discussion of quasar luminosity evolution. Also available at http://www.ociw.edu/~martini/pubs/
Martini, Paul, Weinberg, David H.
openaire +3 more sources
Baryon acoustic oscillations in the Lyα forest of BOSS DR11 quasars [PDF]
, 2014 We report a detection of the baryon acoustic oscillation (BAO) feature in the flux-correlation function of the Ly forest of high-redshift quasars with a statistical significance of five standard deviations.
T. Delubac +37 more
semanticscholar +1 more source
Fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation [PDF]
Monthly notices of the Royal Astronomical Society, 2019 A minority of the optically selected quasar population are red at optical wavelengths due to the presence of dust along the line of sight. A key focus of many red quasar studies is to understand their relationship with the overall quasar population ...
L. Klindt +4 more
semanticscholar +1 more source