Results 71 to 80 of about 5,584 (162)
Frontiers in Astronomy and Space Sciences, 2018 The last 25 years saw a major step forward in the analysis of optical and UV spectroscopic data of large quasar samples. Multivariate statistical approaches have led to the definition of systematic trends in observational properties that are the basis of
Paola Marziani +9 more
doaj +1 more source
Some Constraints on Quasar Progenitors and Quasar Evolution [PDF]
Symposium - International Astronomical Union, 1986 There is strong evidence that quasars are powered by the gravitational energy released by in fall of matter into a compact supermassive object which is most likely a black hole with mass M>106 to 109MO. The question then arises as to how such massive black holes came to be formed. What sort of objects were the progenitors?
openaire +1 more source
The Astrophysical JournalQuasar-driven galactic outflows are a major driver of the evolution of massive galaxies. We report observations of a powerful galactic-scale outflow in a z = 3 extremely red and intrinsically luminous ( L _bol ≃ 5 × 10 ^47 erg s ^−1 ) quasar SDSSJ1652 ...
Andrey Vayner +27 more
doaj +1 more source
Results in Physics, 2019 We report a new stringent limit relating to the space-time variation in the fine-structure constant α=e24πε0ℏc from an analysis of quasar J110325-264515 towards zabs=1.8389. We find Δα/α=(1.56±1.78)×10-6 from a comparison of laboratory wavelengths of [Fe
T.D. Le
doaj +1 more source
Galactic-scale Quasar Pairs from the Sloan Digital Sky Survey and Gaia DR3
The Astrophysical JournalWe perform a systematic search for galactic-scale quasar pairs and small-scale ( 10 ^44.5 erg s ^−1 ) at 0.5
Yuanzhe Jiang +8 more
doaj +1 more source
On Quasar Masses and Quasar Host Galaxies [PDF]
The Astrophysical Journal, 1998 Accepted for publication in ApJ Letters, 7 pages, aas2pp4 ...
openaire +2 more sources
CatNorth: An Improved Gaia DR3 Quasar Candidate Catalog with Pan-STARRS1 and CatWISE
The Astrophysical Journal Supplement SeriesA complete and pure sample of quasars with accurate redshifts is crucial for quasar studies and cosmology. In this paper, we present CatNorth, an improved Gaia Data Release 3 (Gaia DR3) quasar candidate catalog with more than 1.5 million sources in the 3
Yuming Fu +19 more
doaj +1 more source
A Super-Eddington, Lensing-magnified Quasar at z = 5.07 Observed with JWST
The Astrophysical Journal LettersWe present JWST/NIRCam F070W and F480M imaging for a quasar at z = 5.07, J0025–0145, which is magnified by a foreground lensing galaxy. Existing Hubble Space Telescope (HST) imaging does not have sufficient spatial resolution to determine whether the ...
Katherine Panebianco +6 more
doaj +1 more source
Highly Variable Quasar Candidates Selected from 4XMM-DR13 with Machine Learning
The Astrophysical JournalWe present a sample of 12 quasar candidates with highly variable soft X-ray emission, selected from the fourth XMM-Newton Serendipitous Source Catalog (4XMM-DR13), using random forest (RF).
Heng Wang +8 more
doaj +1 more source
Fast Outflow in the Host Galaxy of the Luminous z = 7.5 Quasar J1007+2115
The Astrophysical JournalThe James Webb Space Telescope opens a new window to directly probe luminous quasars powered by billion solar mass black holes in the Epoch of Reionization and their coevolution with massive galaxies with unprecedented details.
Weizhe Liu +26 more
doaj +1 more source