Results 41 to 50 of about 111,241 (293)
The Astronomical Journal, 2023 We present the first results from a new survey for high-redshift ( z ≳ 5) gravitationally lensed quasars and close quasar pairs. We carry out candidate selection based on the colors and shapes of objects in public imaging surveys, then conduct follow-up ...
Minghao Yue +3 more
doaj +1 more source
A luminous quasar at a redshift of z = 7.085 [PDF]
Nature, 2011 The intergalactic medium was not completely reionized until approximately a billion years after the Big Bang, as revealed by observations of quasars with redshifts of less than 6.5.
D. Mortlock +16 more
semanticscholar +1 more source
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
The Faint End of the Quasar Luminosity Function at z ∼ 5 from the Subaru Hyper Suprime-Cam Survey [PDF]
Astrophysical Journal, 2020 We present the quasar luminosity function at z ∼ 5 derived from the optical wide-field survey data obtained as a part of the Subaru strategic program (SSP) with the Hyper Suprime-Cam (HSC).
M. Niida +19 more
semanticscholar +1 more source
EXTENDED SCATTERING ENVELOPE IN THE Q2237+0305 QUASAR
Radio Physics and Radio Astronomy, 2019 Purpose: Studying the accretion disc structure in the Q2237+0305 gravitationally lensed quasar in optical wavelengths; estimation of parameters of the matter accretion regime onto a central black hole.
L. A. Berdina +2 more
doaj +1 more source
magazén, 2022 The city is a set of arbitrary visual experiences dispersed in time that must necessarily be integrated. In studying the absences, Bruno Toscano writes that “the city would appear to us in a less verisimilar facies if we resigned ourselves to consider
Farina, Arianna
doaj +1 more source
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
A Thirty-Four Billion Solar Mass Black Hole in SMSS J2157-3602, the Most Luminous Known Quasar [PDF]
, 2020 From near-infrared spectroscopic measurements of the MgII emission line doublet, we estimate the black hole (BH) mass of the quasar, SMSS J215728.21-360215.1, as being (3.4 +/- 0.6) x 10^10 M_sun and refine the redshift of the quasar to be z=4.692.
Bian, Fuyan +5 more
core +2 more sources
The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample: a tomographic measurement of cosmic structure growth and expansion rate based on optimal redshift weights [PDF]
Monthly notices of the Royal Astronomical Society, 2018 We develop a new method, which is based on the optimal redshift weighting scheme, to extract the maximal tomographic information of baryonic acoustic oscillations (BAO) and redshift space distortions (RSD) from the extended Baryon Oscillation ...
Gong-Bo Zhao +30 more
semanticscholar +1 more source
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