Results 1 to 10 of about 226 (152)

A Candidate Dual QSO at Cosmic Noon

The Astrophysical Journal Letters, 2023
We report the discovery of a candidate dual QSO at z = 1.889, a redshift that is in the era known as “cosmic noon” where most of the universe’s black hole and stellar mass growth occurred.
Eilat Glikman, Rachel Langgin, Makoto A. Johnstone, Ilsang Yoon, Julia M. Comerford, Brooke D. Simmons, Hannah Stacey, Mark Lacy, John M. O’Meara   +8 more
doaj   +1 more source

Statistics of Galactic-scale Quasar Pairs at Cosmic Noon

The Astrophysical Journal, 2023
The statistics of galactic-scale quasar pairs can elucidate our understanding of the dynamical evolution of supermassive black hole (SMBH) pairs, the duty cycles of quasar activity in mergers, or even the nature of dark matter, but they have been ...
Yue Shen, Hsiang-Chih Hwang, Masamune Oguri, Nianyi Chen, Tiziana Di Matteo, Yueying Ni, Simeon Bird, Nadia Zakamska, Xin Liu, Yu-Ching Chen, Kaitlin M. Kratter   +10 more
doaj   +1 more source

A Catalog of Candidate Double and Lensed Quasars from Gaia and WISE Data

The Astrophysical Journal Supplement Series, 2022
Making use of strong correlations between closely separated multiple or double sources and photometric and astrometric metadata in Gaia Early Data Release 3 (EDR3), we generate a catalog of candidate double- and multiply imaged lensed quasars and active ...
Valeri V. Makarov, Nathan J. Secrest
doaj   +1 more source

A Survey for High-redshift Gravitationally Lensed Quasars and Close Quasar Pairs. I. The Discoveries of an Intermediately Lensed Quasar and a Kiloparsec-scale Quasar Pair at z ∼ 5

The Astronomical Journal, 2023
We present the first results from a new survey for high-redshift ( z ≳ 5) gravitationally lensed quasars and close quasar pairs. We carry out candidate selection based on the colors and shapes of objects in public imaging surveys, then conduct follow-up ...
Minghao Yue, Xiaohui Fan, Jinyi Yang, Feige Wang   +3 more
doaj   +1 more source

4C02.27: what is inside a double-double radio quasar? [PDF]

Proceedings of 10th European VLBI Network Symposium and EVN Users Meeting: VLBI and the new generation of radio arrays — PoS(10th EVN Symposium), 2011
4 pages, 2 figures, to appear in the proceedings of the 10th European VLBI Network Symposium (September 20-24, 2010, Manchester, UK).
Frey, S., Paragi, Z.
openaire   +2 more sources

Quasar Luminosity Function at z = 7

The Astrophysical Journal Letters, 2023
We present the quasar luminosity function (LF) at z = 7, measured with 35 spectroscopically confirmed quasars at 6.55 < z < 7.15. The sample of 22 quasars from the Subaru High- z Exploration of Low-Luminosity Quasars (SHELLQs) project, combined with 13 ...
Yoshiki Matsuoka, Masafusa Onoue, Kazushi Iwasawa, Michael A. Strauss, Nobunari Kashikawa, Takuma Izumi, Tohru Nagao, Masatoshi Imanishi, Masayuki Akiyama, John D. Silverman, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Kohei Inayoshi, Rikako Ishimoto, Toshihiro Kawaguchi, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Chien-Hsiu Lee, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Atsushi J. Nishizawa, Masamune Oguri, Yoshiaki Ono, Taira Oogi, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Ayumi Takahashi, Tadafumi Takata, Masayuki Tanaka, Yoshiki Toba, Shiang-Yu Wang, Takuji Yamashita   +43 more
doaj   +1 more source

Varstrometry for Off-nucleus and Dual Subkiloparsec AGN (VODKA). SDSS J1608+2716: A Subarcsecond Quadruply Lensed Quasar at z = 2.575

The Astrophysical Journal Letters, 2023
We report Hubble Space Telescope (HST) Wide Field Camera 3 deep IR (F160W) imaging of SDSS J1608+2716. This system, located at a redshift of z = 2.575, was recently reported as a triple-quasar candidate with subarcsecond separations (∼0.″25) based on ...
Junyao Li, Xin Liu, Yue Shen, Masamune Oguri, Arran C. Gross, Nadia L. Zakamska, Yu-Ching Chen, Hsiang-Chih Hwang   +7 more
doaj   +1 more source

Microlensing in the double quasar SBS 1520+530 [PDF]

Astronomy & Astrophysics, 2005
6 pages, 7 figures.
Gaynullina, E. R., Schmidt, R. W., Akhunov, T., Burkhonov, O., Gottloeber, S., Mirtadjieva, K., Nuritdinov, S. N., Tadjibaev, I., Wambsganss, J., Wisotzki, L.   +9 more
openaire   +2 more sources

Varstrometry for Off-nucleus and Dual Subkiloparsec Active Galactic Nuclei (VODKA): Investigating the Nature of SDSS J0823+2418 at z = 1.81, A Likely Lensed Quasar

The Astrophysical Journal, 2023
Dual quasars at small physical separations are an important precursor phase of galaxy mergers, ultimately leading to the coalescence of the two supermassive black holes.
Arran C. Gross, Yu-Ching Chen, Adi Foord, Xin Liu, Yue Shen, Masamune Oguri, Andy Goulding, Hsiang-Chih Hwang, Nadia L. Zakamska, Yilun Ma, Liam Nolan   +10 more
doaj   +1 more source

Spectroscopic follow-up of double quasar candidates [PDF]

Monthly Notices of the Royal Astronomical Society, 2018
8 pages, 7 figures, 5 tables (full tables 1 and 3-5 are available online in a machine-readable ASCII format at https://grupos.unican.es/glendama/LQLM_results.htm). Accepted for publication in MNRAS (uncorrected version)
Shalyapin, V. N., Sergeyev, A. V., Goicoechea, L. J., Zheleznyak, A. P.   +3 more
openaire   +2 more sources