Results 11 to 20 of about 58,921 (147)
A quasar companion to the puzzling quasar SDSS J0927+2943 [PDF]
Astronomy and Astrophysics, 2010 4 pages, 3 figures.
M. Barattini +4 more
openaire +6 more sources
Quasars and Their Host Galaxies [PDF]
, 2006 This review attempts to describe developments in the fields of quasar and quasar host galaxies in the past five. In this time period, the Sloan and 2dF quasar surveys have added several tens of thousands of quasars, with Sloan quasars being found to z>6. Obscured, or partially obscured quasars have begun to be found in significant numbers.
A. Laor +81 more
openaire +6 more sources
A Hubble Diagram for Quasars [PDF]
Frontiers in Astronomy and Space Sciences, 2015 The cosmological model is at present not tested between the redshift of the farthest observed supernovae (z ~ 1.4) and that of the Cosmic Microwave Background (z ~ 1,100). Here we introduce a new method to measure the cosmological parameters: we show that quasars can be used as "standard candles" by employing the non-linear relation between their ...
Guido Risaliti +4 more
openaire +10 more sources
Symposium - International Astronomical Union, 1994 I review recent results for quasars and discuss how they are related to activity in galaxies. Topics included are studies of quasar host galaxies with HST; searches for quasars in the Hubble Deep Field; evolution of the quasar luminosity function; news highlights from astro-ph; and current observational research problems and their relation to ...
openaire +3 more sources
Do Quasars Lens Quasars? [PDF]
The Astrophysical Journal, 1997 If the unexpectedly high frequency of quasar pairs with very different component redshifts is due to the lensing of a population of background quasars by the foreground quasar, typical lens masses must be $\sim10^{12}M_{\sun}$ and the sum of all such quasar lenses would have to contain $\sim0.005$ times the closure density of the Universe.
openaire +3 more sources
Improved redshifts for SDSS quasar spectra [PDF]
, 2010 A systematic investigation of the relationship between different redshift estimation schemes for more than 91000 quasars in the Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6) is presented.
Abazajian +30 more
core +2 more sources
A Main Sequence for Quasars [PDF]
Frontiers in Astronomy and Space Sciences, 2018 Invited talk presented at the Padova Conference on "Quasars at all cosmic epochs"; to appear in Frontiers of Astrophysics and Space ...
Marziani, Paola +9 more
openaire +7 more sources
Tracing high redshift cosmic web with quasar systems [PDF]
, 2014 We trace the cosmic web at redshifts 1.0
Einasto, Jaan +8 more
core +1 more source
Quasars Probing Quasars. I. Optically Thick Absorbers near Luminous Quasars [PDF]
The Astrophysical Journal, 2006 With close pairs of quasars at different redshifts, a background quasar sightline can be used to study a foreground quasar's environment in absorption. We search 149 moderate resolution background quasar spectra, from Gemini, Keck, the MMT, and the SDSS to survey Lyman Limit Systems (LLSs) and Damped Ly-alpha systems (DLAs) in the vicinity of 1.8 < ...
Scott Burles +13 more
openaire +4 more sources
A slitless spectroscopic survey for quasars near quasars [PDF]
Astronomy & Astrophysics, 2008 18 pages, 16 figures, accepted by A&A, includes Table 2 from online material, full paper with appendices containing additional figures and tables available at http://www.aip.de/People/gworseck/qnqpaper/qnqpaper_final ...
Lutz Wisotzki +2 more
openaire +4 more sources