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Red quasars are thought to be an intermediate population between merger-driven star-forming galaxies in dust-enshrouded phase and normal quasars. If so, they are expected to have high accretion ratios, but their intrinsic dust extinction…

Astrophysics of Galaxies · Physics 2015-10-15 Dohyeong Kim , Myungshin Im , Eilat Glikman , Jong-Hak Woo , Tanya Urrutia

Over the past decades, nearly a million quasars have been explored to shed light on the evolution of supermassive black holes and galaxies. The ultraviolet-to-optical spectra of type-1 quasars particularly offer insights into their black…

Astrophysics of Galaxies · Physics 2024-08-09 Yongjung Kim , Dohyeong Kim , Myungshin Im , Minjin Kim

We have cross-correlated the SDSS DR3 Schneider et al. (2005) quasar catalog with the XMM-Newton archive. Color and redshift selections (g - r > 0.5 and 0.9 z < 2.1) result in a sample of 17 red, moderate redshift quasars. The redshift…

Astrophysics · Physics 2009-09-28 Monica Young , Martin Elvis , Guido Risaliti

Webster et al (1995) claimed that up to 80% of QSOs may be obscured by dust. They inferred the presence of this dust from the remarkably broad range of B-K optical-infrared colours of a sample of flat-spectrum PKS radio QSOs. If such dust…

Astrophysics · Physics 2009-10-30 C. R. Benn , M. Vigotti , R. Carballo , J. I. Gonzalez-Serrano , S. F. Sanchez

We present results of a study of 12 dust-reddened quasars with 0.4 < z < 2.65 and reddenings in the range 0.15 < E(B-V) < 1.7. We obtained ACIS-S X-ray spectra of these quasars, estimated the column densities towards them, and hence…

Astrophysics · Physics 2009-11-10 Tanya Urrutia , Mark Lacy , Michael D. Gregg , Robert H. Becker

We present short \chandra observations of twelve bright (i<18) z_em~1.5 quasars from the Sloan Digital Sky Survey chosen to have significantly redder optical colors than most quasars at the same redshift. Of the five quasars with optical…

A non-negligible fraction of quasars are red at optical wavelengths, indicating (in the majority of cases) that the accretion disc is obscured by a column of dust which extinguishes the shorter-wavelength blue emission. In this paper, we…

Astrophysics of Galaxies · Physics 2021-11-24 V. A. Fawcett , D. M. Alexander , D. J. Rosario , L. Klindt

We present a sample of 120 dust-reddened quasars identified by matching radio sources detected at 1.4 GHz in the FIRST survey with the near-infrared 2MASS catalog and color-selecting red sources. Optical and/or near-infrared spectroscopy…

We investigate the continuum and emission line properties of 4576 SDSS quasars as a function of their optical/UV SEDs. The optical/UV color distribution of our sample is roughly Gaussian, but with a red tail; we distinguish between 1)…

Combining radio observations with optical and infrared color selection -- demonstrated in our pilot study to be an efficient selection algorithm for finding red quasars -- we have obtained optical and infrared spectroscopy for 120 objects…

We have measured the near-infrared colors and the fluxes of individual pixels in 68 galaxies common to the Spitzer Infrared Nearby Galaxies Survey and the Large Galaxy Atlas Survey. Each galaxy was separated into regions of increasingly red…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Erin Mentuch , Roberto Abraham , Stefano Zibetti

We present Hubble ACS images of thirteen dust reddened Type-1 quasars selected from the FIRST/2MASS Red Quasar Survey. These quasars have high intrinsic luminosities after correction for dust obscuration (-23.5 > M_B > -26.2 from…

Astrophysics · Physics 2009-11-13 Tanya Urrutia , Mark Lacy , Robert H. Becker

We explore the form of extragalactic reddening toward quasars using a sample of 9566 quasars with redshifts 0<z<2.2, and accurate optical colors from the Sloan Digital Sky Survey (SDSS). We confirm that dust reddening is the primary…

We have recently found fundamental differences in the radio properties of red quasars when compared to typical blue quasars. In this paper we use X-shooter data, providing spectral coverage from $\sim 3000-25000$ Ang, of a sample of 40 red…

Astrophysics of Galaxies · Physics 2022-11-21 V. A. Fawcett , D. M. Alexander , D. J. Rosario , L. Klindt , E. Lusso , L. K. Morabito , G. Calistro Rivera

We explore the connection between absorption by neutral gas and extinction by dust in mid-infrared (IR) selected luminous quasars. We use a sample of 33 quasars at redshifts 0.7 < z < 3 in the 9 deg^2 Bo\"otes multiwavelength survey field…

Astrophysics of Galaxies · Physics 2014-06-25 Shawn M. Usman , Stephen S. Murray , Ryan C. Hickox , Mark Brodwin

A majority of quasar surveys have been based on criteria which assume strong blue continua or a UV-excess. Any amount of dust along the line-of-sight is expected to drastically extinguish the optical/UV flux leading to a selection bias.…

Astrophysics · Physics 2007-05-23 Frank J. Masci

We investigate the luminosity and redshift dependence of the quasar continuum by means of composite spectrum using a large non-BAL radio-quiet quasar sample drawn from the Sloan Digital Sky Survey. Quasar continuum slopes in the UV-Opt band…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 Xiaoyi Xie , Shiyin Shen , Zhengyi Shao , Jun Yin

Context. Observations of quasars shining through foreground galaxies, offer a way to probe the dust extinction curves of distant galaxies. Interesting objects for this study are found in strong gravitational lensing systems, where the…

Astrophysics · Physics 2009-11-13 Linda Ostman , Ariel Goobar , Edvard Mortsell

A minority of the optically selected quasar population are red at optical wavelengths due to the presence of dust along the line-of-sight. A key focus of many red quasar studies is to understand their relationship with the overall quasar…

Astrophysics of Galaxies · Physics 2019-07-10 Lizelke Klindt , David M. Alexander , David J. Rosario , Elisabeta Lusso , Sotiria Fotopoulou

The Sloan Digital Sky Survey can be used to detect and characterize red and reddened quasars. In Richards et al. (2003), we showed that 6% of SDSS quasars have red colors consistent with significant dust reddening by an extinction curve…

Astrophysics · Physics 2007-05-23 Patrick B. Hall , Philip Hopkins , Michael Strauss , Gordon Richards , J. Brinkmann
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