Results 31 to 40 of about 515 (214)
A Close-Separation Double Quasar Lensed by a Gas-rich Galaxy [PDF]
The Astronomical Journal, 2000 In the course of a Cycle 8 snapshot survey, we have discovered that the z=1.565 quasar HE 0512-3329 is a double with image separation 0.644", almost certainly due to gravitational lensing. The two components differ in brightness by only 0.4 magnitudes and a high signal-to-noise ground-based composite optical spectrum shows no trace of any stellar ...
Gregg, Michael D. +7 more
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A catalogue of quasars and active nuclei: 12th edition [PDF]
, 2006 Aims.This catalogue is aimed at presenting a compilation of all known AGN in a compact and convenient form and we hope that it will be useful to all workers in this field.
P. Véron, M.-P. Véron-Cetty
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Redshifts and lens profile for the double quasar QJ 0158-4325 [PDF]
Astronomy & Astrophysics, 2009 Research Note, Accepted for publication in A& ...
Faure C. +7 more
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A catalogue of quasars and active nuclei: 13th edition [PDF]
, 2010 Aims. This catalogue is aimed at presenting a compilation of all known AGN in a compact and convenient form, and we hope that it will be useful to all workers in this field. Methods.
P. Véron, M.-P. Véron-Cetty
core +1 more source
Revisiting X-Ray-bright Optically Normal Galaxies with the Chandra Source Catalog
The Astrophysical Journal, 2023 X-ray bright optically normal galaxies (XBONGs) are galaxies with X-ray luminosities consistent with those of active galactic nuclei (AGNs) but no evidence of AGN optical emission lines.
Dong-Woo Kim +5 more
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The discovery and characterization of the most distant quasars [PDF]
, 2015 Luminous quasars at high redshift (z>5.5) provide direct probes of the growth of supermassive black holes and their host galaxies at the epoch of cosmic reionization, which is one of the current frontiers of astrophysical research.
Banados Torres, Eduardo
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Parsec-Scale Structure in the Nuclei of Double-Lobed Radio Quasars [PDF]
, 1986 A complete sample of double-lobed quasars is defined, which is believed to be randomly oriented and which contains many objects with central components accessible to very-long-baseline interferometry (VLSI). The purpose of defining the sample in this way
Hough, David Hans
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A tale of two double quasars: Hubble constant tension or biases? [PDF]
, 2023 For a flat ΛCDM (standard) cosmology, a small sample of gravitationally lensed quasarswith measured time delays has recently provided a value of the Hubble constantH0intension with thePlanckflat ΛCDM result. Trying to check if this tension is real or not,
Goicoechea Santamaría, Luis Julián +1 more
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Three quasars from a survey of strong 25-μm emitters [PDF]
, 2000 We have carried out a spectroscopic survey of 750 sources that are strong 25-μm emitters from the IRAS Faint Source data base. Many of these sources are previously unknown active galactic nuclei including new IRAS quasars, three of which we describe here:
Wolstencroft, Ramon D. +3 more
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The double quasar Q2138-431: detection of a lensing galaxy [PDF]
Monthly Notices of the Royal Astronomical Society, 2021 ABSTRACT This paper reviews the question of whether the wide separation double quasar Q2138-431 is a gravitational lens. From early work, the two quasar images are known to have almost identical spectra and redshifts, but no lensing galaxy has so far been detected.
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