Results 111 to 120 of about 111,241 (293)
Hubble Space Telescope Ultraviolet Spectroscopy of Fourteen Low-Redshift Quasars [PDF]
, 2006 We present low-resolution ultraviolet spectra of 14 low redshift ...
Ari Laor +38 more
core +4 more sources
Frontiers in Astronomy and Space Sciences, 2018 Here we investigate the connection of broad emission line shapes and continuum light curve variability time scales of type-1 Active Galactic Nuclei (AGN).
Edi Bon +4 more
doaj +1 more source
THE FINAL SDSS HIGH-REDSHIFT QUASAR SAMPLE OF 52 QUASARS AT z > 5.7 [PDF]
, 2016 We present the discovery of nine quasars at identified in the Sloan Digital Sky Survey (SDSS) imaging data. This completes our survey of quasars in the SDSS footprint.
Linhua Jiang +16 more
semanticscholar +1 more source
Understanding extreme quasar optical variability with CRTS – II. Changing-state quasars [PDF]
Monthly notices of the Royal Astronomical Society, 2019 We present the results of a systematic search for quasars in the Catalina Real-time Transient Survey exhibiting both strong photometric variability and spectroscopic variability over a decadal baseline. We identify 111 sources with specific patterns of
M. Graham +10 more
semanticscholar +1 more source
Magnetic Resonance in Medicine, Volume 94, Issue 5, Page 2173-2189, November 2025.Abstract Purpose To develop a novel MR fingerprinting sequence using optimized motion‐compensated diffusion preparations for simultaneous T1, T2, and ADC quantification of liver tissue in a single breath‐held scan. Methods A radial spoiled gradient echo acquisition with magnetization preparation modules for T1, T2, and ADC encoding is proposed.
C. Velasco +7 more
wiley +1 more source
Quasars Probing Quasars. IX. The Kinematics of the Circumgalactic Medium Surrounding z ∼ 2 Quasars [PDF]
The Astrophysical Journal, 2018 Abstract We examine the kinematics of the gas in the environments of galaxies hosting quasars at z ∼ 2. We employ 148 projected quasar pairs to study the circumgalactic gas of the foreground quasars in absorption. The sample selects foreground quasars with precise redshift measurements, using emission lines with precision ≲300 km s−1 and
Marie Wingyee Lau +2 more
openaire +4 more sources
Towards an Understanding of Changing-Look Quasars: An Archival Spectroscopic Search in SDSS
, 2016 The uncertain origin of the recently-discovered `changing-looking' quasar phenomenon -- in which a luminous quasar dims significantly to a quiescent state in repeat spectroscopy over ~10 year timescales -- may present unexpected challenges to our ...
Anderson, Scott F. +15 more
core +2 more sources
Frontiers in Astronomy and Space Sciences, 2017 Prior to the Fermi-LAT era, only two classes of Active Galactic Nuclei (AGN) were thought to harbor relativistic jets that radiate up to gamma-ray energies: blazars and radio galaxies. The detection of variable gamma-ray emission from Narrow Line Seyfert
Maialen Arrieta-Lobo +2 more
doaj +1 more source
Development and demonstration of end‐to‐end testing for intra‐fraction motion‐managed workflows
Medical Physics, Volume 52, Issue 9, September 2025.Abstract Background Intra‐fraction motion management techniques, including beam gating and intra‐fraction drift correction (IDC), have recently been introduced on the Unity MR‐linac (Elekta AB, Stockholm, Sweden) to mitigate the dosimetric impact of motion during treatment.
Stijn Oolbekkink +4 more
wiley +1 more source
The Clustering of Simulated Quasars [PDF]
AIP Conference Proceedings, 2009 We analyze the clustering properties of quasars simulated using a semianalytic model built on the Millennium Simulation, with the goal of testing scenarios in which black hole accretion and quasar activity are triggered by galaxy mergers. When we select quasars with luminosities in the range accessible by current observations, we find that predicted ...
Silvia Bonoli +2 more
openaire +4 more sources