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Related papers: The FIRST-2MASS Red Quasar Survey

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We present details of a new sample of radio-loud quasars drawn from 0.013 sr of the 7C Redshift Survey. This sample is small (21 quasars) but complete in that every object with an unresolved nucleus and/or broad emission lines with…

Astrophysics · Physics 2016-01-27 Chris J. Willott , Steve Rawlings , Katherine M. Blundell , Mark Lacy

We have used the VLA FIRST survey and the APM catalog of the POSS-I plates as the basis for constructing a new radio-selected sample of optically bright quasars. This is the first radio-selected sample that is competitive in size with…

We describe the selection of candidate radio-loud quasars obtained by cross-matching radio source positions from the low-frequency (151 MHz) 7C survey with optical positions from five pairs of EO POSS-I plates scanned with the Cambridge…

We present results on a survey to find extremely dust-reddened Type-1 Quasars. Combining the FIRST radio survey, the 2MASS Infrared Survey and the Sloan Digital Sky Survey, we have selected a candidate list of 122 potential red quasars.…

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

We present optical spectra for a representative sample of 27 nearby (z < 0.2) 2MASS-selected AGN with red near-IR colours (J-K 2.0). The spectra were taken with the ISIS spectrograph on the WHT with the aim of determining the nature of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Marvin Rose , Clive Tadhunter , Joanna Holt , Javier Rodríguez Zaurín

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

The sub-population of quasars reddened by intrinsic or intervening clouds of dust are known to be underrepresented in optical quasar surveys. By defining a complete parent sample of the brightest and spatially unresolved quasars in the…

High Energy Astrophysical Phenomena · Physics 2016-10-26 K. E. Heintz , J. P. U. Fynbo , P. Møller , B. Milvang-Jensen , J. Zabl , N. Maddox , J. -K. Krogager , S. Geier , M. Vestergaard , P. Noterdaeme , C. Ledoux

We discuss the relative merits of mid-infrared and X-ray selection of type-2 quasars. We describe the mid-infrared, near-infrared and radio selection criteria used to find a population of redshift z~2 type-2 quasars which we previously…

Red quasars are very red in the optical through near-infrared (NIR) wavelengths, which is possibly due to dust extinction in their host galaxies as expected in a scenario in which red quasars are an intermediate population between…

Astrophysics of Galaxies · Physics 2018-02-28 Dohyeong Kim , Myungshin Im

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 a sample of 8498 quasars with both SDSS $ugriz$ optical and UKIDSS $YJHK$ near-IR photometric data. With this sample, we obtain the median colour-z relations based on 7400 quasars with magnitude uncertainties less than 0.1mag in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Xue-Bing Wu , Zhendong Jia

We combine deep, wide-field near-IR and optical imaging to demonstrate a reddening-independent quasar selection technique based on identifying outliers in the (g-z) / (z-H) colour diagram. In three fields covering a total of ~0.7 deg^2 to a…

Astrophysics · Physics 2009-11-07 R. G. Sharp , C. N. Sabbey , A. K. Vivas , A. Oemler , R. G. McMahon , S. T. Hodgkin , P. S. Coppi

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)…

We have obtained complete redshift information for a sample of 442 radio-loud quasars with flux densities S(11cm) >= 0.25Jy. These come from a completely-identified sample of 878 flat-spectrum radio sources, so there is no optical magnitude…

Astrophysics · Physics 2007-05-23 P. A. Shaver , I. M. Hook , C. A. Jackson , J. V. Wall , K. I. Kellermann

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

The identifications of quasars in the redshift range 2.2<z<3 are known to be very inefficient as their optical colors are indistinguishable from those of stars. Recent studies have proposed to use optical variability or near-IR colors to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Xue-Bing Wu , Ran Wang , Kasper B. Schmidt , Fuyan Bian , Linhua Jiang , Xiaohui Fan

We present the method and first results of a survey for high-redshift (z>3) radio-loud quasars, which is based on optical identifications of 2902 flat-spectrum radio sources with S(5GHz)>= 25mJy. The radio sample was defined over a 1600 sq…

Astrophysics · Physics 2009-10-30 I. M. Hook , R. H. Becker , R. G. McMahon , R. L. White

In a survey of quasar candidates selected by matching the FIRST and 2MASS catalogs, we have found two extraordinarily red quasars. FIRST J013435.7-093102 is a 1 Jy source at z=2.216 and has B-K > 10, while FIRST J073820.1+275045 is a 2.5…

The results of a large area, ~600 deg^2, K-band flux-limited spectroscopic survey for luminous quasars are presented. The survey utilises the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) in regions of sky within the Sloan…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Natasha Maddox , Paul C. Hewett , Celine Peroux , Daniel B. Nestor , Lutz Wisotzki