Results 1 to 10 of about 86,681 (283)

Do Quasars Lens Quasars? [PDF]

The Astrophysical Journal, 1996
If the unexpectedly high frequency of quasar pairs with very different component redshifts is due to the lensing of a population of background quasars by the foreground quasar, typical lens masses must be $\sim10^{12}M_{\sun}$ and the sum of all such ...
Boyle B. J., Boyle B. J., Burbidge E. M., E. J. Wampler, Iovino A., Shaver P. A., Zitelli V.   +6 more
core   +5 more sources

A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan Digital Sky Survey [PDF]

Astrophys.J.679:962-966,2008, 2008
We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 \AA) at 1.7 < z < 4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release. These nitrogen-rich (N-rich) objects comprise ~1.1% of the SDSS quasars.
Fan, Xiaohui, Jiang, Linhua, Vestergaard, M.   +2 more
arxiv   +5 more sources

Discovery of spectacular quasar-driven superbubbles in red quasars. [PDF]

Sci Adv, 2023
Quasar-driven outflows on galactic scales are a routinely invoked ingredient for galaxy formation models. We report the discovery of ionized gas nebulae surrounding three luminous red quasars at z ~ 0.4 from Gemini integral field unit observations.
Shen L, Liu G, He Z, Zakamska NL, Glikman E, Greene JE, Hu W, Mou G, Wylezalek D, Rupke DSN.   +9 more
europepmc   +4 more sources

On the link between associated MgII absorbers and star formation in quasar hosts [PDF]

, 2011
A few percent of quasars show strong associated MgII absorption, with velocities (v_off) lying within a few thousand km/s from the quasar systemic redshift. These associated absorption line systems (AALs) are usually interpreted as absorbers that are either intrinsic to the quasar and its host, or arising from external galaxies clustering around the ...
Bahcall, Bergeron, Brice Ménard, Canalizo, Glikman, Hennawi, Ho, Hopkins, Hopkins, Richards, Richards, Schneider, Shen, Shen, Steidel, Tremaine, Urrutia, Vanden Berk, Vanden Berk, Veilleux, Wyithe, Yue Shen, Zhu   +22 more
arxiv   +3 more sources

Predicting the Yields of z > 6.5 Quasar Surveys in the Era of Roman and Rubin [PDF]

The Astrophysical Journal, 2023
About 70 luminous quasars discovered at z > 6.5 are strongly biased toward the bright end, thus not providing a comprehensive view of quasar abundance beyond the cosmic dawn. We present the predicted results of the Roman/Rubin high-redshift quasar survey,
Wei Leong Tee, Xiaohui Fan, Feige Wang, Jinyi Yang, Sangeeta Malhotra, James E. Rhoads   +5 more
doaj   +2 more sources

A slitless spectroscopic survey for quasars near quasars [PDF]

Astronomy & Astrophysics, 2008
We present the results of the Quasars near Quasars (QNQ) survey, a CCD-based slitless spectroscopic survey for faint ...
Adelberger, Appenzeller, Baade, Barbieri, Barger, Becker, Bergeron, Bohuski, Bongiovanni, Chand, Ciliegi, Clowes, Clowes, Cowie, Crampton, Crampton, Croom, Crotts, D'Odorico, D'Odorico, Dinshaw, F. Selman, Francis, G. Worseck, Gaskell, Gratton, Hawkins, Hazard, Hazard, Hazard, Heap, Hennawi, Hennawi, Hennawi, Hewett, Hewett, Hewitt, Hook, Horne, Jakobsen, Jakobsen, Jakobsen, Jakobsen, Jauncey, Jiang, Kim, Krumpe, L. Wisotzki, La Franca, Landolt, Liske, Lopez, Maza, Maza, McIntosh, McMahon, Morris, Murphy, Osmer, Osmer, Osmer, Pascual, Pichon, Prescott, Reimers, Reimers, Richards, Richards, Salzer, Schmidt, Schmidt, Schneider, Schneider, Schneider, Sharp, Shaver, Smette, Sramek, Steidel, Storrie-Lombardi, Szokoly, Trump, Tytler, Vanden Berk, Véron, Warren, Williger, Williger, Wisotzki, Wisotzki, Wolf, Wolf, Worseck, Worseck, Wright, Zheng, Zitelli   +96 more
core   +5 more sources

Extreme Quasars as Distance Indicators in Cosmology

Frontiers in Astronomy and Space Sciences, 2020
Quasars accreting matter at very high rates (known as extreme Population A [xA] quasars, possibly associated with super-Eddington accreting massive black holes) may provide a new class of distance indicators covering cosmic epochs from present day up to ...
Paola Marziani, A Del Olmo, Mauro D’onofrio   +2 more
exaly   +3 more sources

Dust-free quasars in the early Universe

Nature, 2010
The most distant quasars known, at redshifts z=6, generally have properties indistinguishable from those of lower-redshift quasars in the rest-frame ultraviolet/optical and X-ray bands. This puzzling result suggests that these distant quasars are evolved
Linhua Jiang, Xiaohui Fan, W N Brandt
exaly   +3 more sources

Highly Accreting Quasars at High Redshift

Frontiers in Astronomy and Space Sciences, 2018
We present preliminary results of a spectroscopic analysis for a sample of type 1 highly accreting quasars (L/LEdd ~ 1.0) at high redshift, z ~2–3.
Andreas Heinz, A Del Olmo, Paola Marziani   +2 more
exaly   +3 more sources

Quasars and their host galaxies [PDF]

, 2006
This review attempts to describe developments in the fields of quasar and quasar host galaxies in the past five. In this time period, the Sloan and 2dF quasar surveys have added several tens of thousands of quasars, with Sloan quasars being found to z>6. Obscured, or partially obscured quasars have begun to be found in significant numbers.
arxiv   +6 more sources