Results 91 to 100 of about 91,098 (240)
, 2012 Quasars with redshifts greater than 4 are rare, and can be used to probe the structure and evolution of the early universe. Here we report the discovery of six new quasars with $i$-band magnitudes brighter than 19.5 and redshifts between 2.4 and 4.6 from
Chen-Wei Yang +33 more
core +1 more source
Journal of Applied Clinical Medical Physics, Volume 26, Issue 4, April 2025.Abstract Purpose This work describes a single institution experience of commissioning a real‐time target tracking and beam control system, known as comprehensive motion management, for a 1.5 T Elekta MR‐Linac. Methods Anatomical tracking and radiation beam control were tested using the MRI4D Quasar motion phantom.
Blake R Smith +2 more
wiley +1 more source
A further discussion on quasar-galaxy associations from gravitational lensing [PDF]
Astron.Astrophys.286:748-752,1994, 1993 Quasar-galaxy associations, if they result from the effect of gravitational lensing by foreground galaxies, depend sensitively on the shape of the quasar number counts. Two kinds of quasar number-magnitude relations are predicted to produce quite different properties in quasar-galaxy associations: the counts of Boyle, Shanks and Peterson (1988; BSP ...
arxiv
Machine Learning–based Search of High-redshift Quasars
The Astrophysical Journal Supplement SeriesWe present a machine learning search for high-redshift (5.0 < z < 6.5) quasars using the combined photometric data from the Dark Energy Spectroscopic Instrument (DESI) Imaging Legacy Surveys and the Wide-field Infrared Survey Explorer survey.
Guangping Ye, Huanian Zhang, Qingwen Wu
doaj +1 more source
Optical and radio properties of giant radio quasars: Central black hole characteristics
, 2012 We analysed the optical and radio properties of lobe-dominated giant-sized (> 0.72 Mpc) radio quasars and compared the results with those derived for a sample of smaller radio sources to determine whether the large size of some extragalactic radio ...
Jamrozy, M., Kuźmicz, A.
core +1 more source
The Sloan Digital Sky Survey Quasar Lens Search. V. Final Catalog from the Seventh Data Release
, 2012 We present the final statistical sample of lensed quasars from the Sloan Digital Sky Survey (SDSS) Quasar Lens Search (SQLS). The well-defined statistical lens sample consists of 26 lensed quasars brighter than i=19.1 and in the redshift range of 0 ...
Abazajian +115 more
core +1 more source
Comment on "Biases in the Quasar Mass-Luminosity Plane" [PDF]
arXiv, 2010 Comment on "Biases in the Quasar Mass-Luminosity Plane"
arxiv
The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
, 2016 We present the discovery of nine quasars at $z\sim6$ identified in the Sloan Digital Sky Survey (SDSS) imaging data. This completes our survey of $z\sim6$ quasars in the SDSS footprint.
Banados, Eduardo +16 more
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The Detection Rate of Associated Mg ii Absorption Lines in Quasars Depends on Their Radio Emission
The Astrophysical JournalIn active galactic nuclei, jet-driven feedback plays a significant role in influencing the properties of gas within their host galaxy and the circumgalactic medium.
Zhi-Fu Chen, Luis C. Ho
doaj +1 more source
X-ray Insights into the Nature of Quasars with Redshifted Broad Absorption Lines
, 2017 We present $Chandra$ observations of seven broad absorption line (BAL) quasars at $z=0.863$-2.516 with redshifted BAL troughs (RSBALs). Five of our seven targets were detected by $Chandra$ in 4-13 ks exposures with ACIS-S. The $\alpha_{\rm ox}$ values, $\
Ahmed, N. S. +10 more
core +2 more sources