English
Related papers

Related papers: The evolution of dusty torus covering factor in qu…

200 papers

We explore the extinction/reddening of ~35,000 uniformly selected quasars with 0<z<5.3 in order to better understand their intrinsic optical/ultraviolet spectral energy distributions. Using rest-frame optical-UV photometry taken from the…

The redshift range from 2.2 to 3, is known as the 'redshift desert' of quasars because quasars with redshift in this range have similar optical colors as normal stars and are thus difficult to be found in optical sky surveys. A quasar…

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

The quasar sample selected by cross-correlating the FIRST and the 2dF Quasar Redshift Surveys allows us to explore, for the first time, the faint end of the radio and optical luminosity functions up to z = 2.2. We find indications (~3…

Astrophysics · Physics 2009-11-10 M. Cirasuolo , M. Magliocchetti , A. Celotti

(abridged) This paper is the second part of a work investigating the properties of dusty tori in AGN by means of multi-component SED fitting. It focuses on low luminosity, low redshift (z < 0.25) AGN selected among emission line galaxies as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Evanthia Hatziminaoglou , Jacopo Fritz , Tom Jarrett

We identify a sample of 324 red and 273 blue face-on spiral galaxies selected from 115 low-redshift (0.014 < z < 0.18) galaxy clusters imaged with CFHT+MegaCam in u- and r-band, KPNO 0.9-meter 2TKA and MOSAIC 8K camera in B and Rc, and…

This is the second paper in a series on a new luminous z ~ 5 quasar survey using optical and near-infrared colors. Here we present a new determination of the bright end of the quasar luminosity function (QLF) at z ~ 5. Combined our 45 new…

We present a new redshift survey, the 2dF Quasar Dark Energy Survey pilot (2QDESp), which consists of ${\approx}10000$ quasars from ${\approx}150$ deg$^2$ of the southern sky, based on VST-ATLAS imaging and 2dF/AAOmega spectroscopy.…

We present a detailed interpretation of the spectrum of the cosmic infrared background longwards of 5 microns and of galaxy counts from various surveys at mid-infrared, far-infrared and submillimeter wavelengths by evolving the mid-infrared…

Astrophysics · Physics 2009-11-06 R. Chary , D. Elbaz

We determine the 22$\mu$m luminosity evolution and luminosity function for quasars from a data set of over 20,000 objects obtained by combining flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey Explorer…

Astrophysics of Galaxies · Physics 2016-11-09 J. Singal , J. George , A. Gerber

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 fitted Spitzer/IRS ~2-35 um spectra of 26 luminous QSOs in attempt to define the main emission components. Our model has three major components: a clumpy torus, dusty narrow line region (NLR) clouds and a blackbody-like dust. The models…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Rivay Mor , Hagai Netzer , Moshe Elitzur

We aim to study the statistical properties of dusty star-forming galaxies, such as their number counts, luminosity functions (LF) and dust-obscured star-formation rate density (SFRD). We use state-of-the-art de-blended Herschel catalogue in…

Astrophysics of Galaxies · Physics 2019-04-17 L. Wang , W. J. Pearson , W. Cowley , J. W. Trayford , M. Bethermin , C. Gruppioni , P. Hurley , M. J. Michalowski

We have used the 2dF instrument on the AAT to obtain redshifts of a sample of z<3, 18.0<g<21.85 quasars selected from SDSS imaging. These data are part of a larger joint programme: the 2dF-SDSS LRG and QSO Survey (2SLAQ). We describe the…

We present simulations of quasar colors, magnitudes, and numbers at redshifts 5<z<10 based on our discovery of ten new high-redshift quasars and the cloning of lower redshift Sloan Digital Sky Survey (SDSS) quasars. The ten quasars have…

The spectral energy distributions (SEDs) of dust-enshrouded galaxies with powerful restframe far-infrared emission have been constrained by a range of ground-based and space-borne surveys. The IRAS catalog provides a reasonably complete…

Astrophysics · Physics 2009-11-10 Andrew W. Blain , Scott C. Chapman , Ian Smail , Rob Ivison

[Abridged]We exploit a large homogeneous dataset to derive a self-consistent picture of IR emission based on the time-dependent 24, 15, 12 and 8micron monochromatic and bolometric IR luminosity functions (LF) over the 0<z<2.5 redshift…

We present an empirical investigation of the colors of quasars in the Sloan Digital Sky Survey (SDSS) photometric system. The sample studied includes 2625 quasars with SDSS photometry. The quasars are distributed in a 2.5 degree wide stripe…

We present near-infrared spectroscopy and imaging of the compact steep- spectrum radio source 3C 318 which shows it to be a quasar at redshift z=1.574 (the z=0.752 value previously reported is incorrect). 3C 318 is an IRAS, ISO and SCUBA…

Astrophysics · Physics 2009-10-31 Chris J. Willott , Steve Rawlings , Matt J. Jarvis

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