Results 21 to 30 of about 85,255 (272)

A Thirty-Four Billion Solar Mass Black Hole in SMSS J2157-3602, the Most Luminous Known Quasar [PDF]

open access: yes, 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

EXTENDED SCATTERING ENVELOPE IN THE Q2237+0305 QUASAR

open access: yesRadio 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

Improved redshifts for SDSS quasar spectra [PDF]

open access: yes, 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   +3 more sources

Autosomal Dominant Leukodystrophy: A Disease of the Nuclear Lamina

open access: yesFrontiers in Cell and Developmental Biology, 2019
The nuclear lamina is a fibrous meshwork of proteins found adjacent to the inner nuclear membrane that plays a critical role in the maintenance of nuclear architecture.
Quasar S. Padiath
doaj   +1 more source

First Measurement of the Clustering Evolution of Photometrically-Classified Quasars [PDF]

open access: yes, 2005
We present new measurements of the quasar autocorrelation from a sample of \~80,000 photometrically-classified quasars taken from SDSS DR1. We find a best-fit model of $\omega(\theta) = (0.066\pm^{0.026}_{0.024})\theta^{-(0.98\pm0.15)}$ for the angular ...
Adam D. Myers   +15 more
core   +2 more sources

Circum-Galactic Medium in the Halo of Quasars

open access: yesFrontiers in Astronomy and Space Sciences, 2017
The properties of circum-galactic gas in the halo of quasar host galaxies are investigated analyzing Mg II 2800 and C IV 1540 absorption-line systems along the line of sight close to quasars.
Riccardo Ottolina   +6 more
doaj   +1 more source

Quasars at 25

open access: yesScience, 1986
In the quarter century since the first optical identification of a "radio star" (3C 48), astronomers have come to general agreement that the underlying quasar energy source is accretion onto a massive black hole. There is much less agreement on the detailed physics of the processes by which this energy is converted to the forms observed, but this has ...
Trimble, Virginia, Woltjer, Lodewijk
openaire   +4 more sources

Cosmology With Quasars: Predictions for eROSITA From a Quasar Hubble Diagram

open access: yesFrontiers in Astronomy and Space Sciences, 2020
The effort for understanding the matter and energy content of the Universe and its evolution relies on different probes, such as cosmic background radiation, cluster lensing, supernovae.
Elisabeta Lusso, Elisabeta Lusso
doaj   +1 more source

Do Quasars Lens Quasars? [PDF]

open access: yesThe 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   +2 more sources

Quasar-galaxy associations [PDF]

open access: yesMonthly Notices of the Royal Astronomical Society, 1995
uuencoded Postscript file (including figures and tables), SUSSEX-AST 94/8 ...
Thomas, P. A.   +2 more
openaire   +5 more sources

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