Dust Reddening in Sloan Digital Sky Survey Quasars

By P. Hopkins, M. Strauss, P. Hall, Gordon Richards, A. S. Cooper, D. Schneider, D. V. vanden Berk, S. Jester, J. Brinkmann, G. Szokoly. 2004

207 citations recorded by the source corpus.

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 explanation for the red "tail" of the color distribution of SDSS quasars. Our fitting to five-band photometry normalized by the modal quasar color as a function of redshift shows that this tail is well described by SMC-like reddening but not by reddening that is LMC-like, Galactic, or as recently described by Gaskell and coworkers. Extension to longer wavelengths using a subset of 1886 SDSS–Two Micron All Sky Survey matches confirms these results at high significance. We carry out Monte Carlo simulations that match the observed distribution of quasar spectral energy distributions using a Lorentzian dust-reddening distribution; 2% of quasars selected by the main SDSS targeting algorithm (i.e., that are not extincted out of the sample) have EB-V > 0.1, and less than 1% have EB-V > 0.2, where the extinction is relative to quasars with modal colors. Reddening is uncorrelated with the presence of intervening narrow-line absorption systems, but reddened quasars are much more likely to show narrow absorption at the redshift of the quasar than are unreddened quasars. Thus the reddening toward quasars is dominated by SMC-like dust at the quasar redshift.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/8d3d8fc65f84a7472e2a9c2ea195d9db6b8106e2

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Early Data Release (2003, background): “However, a significant fraction of quasars show evidence of dust reddening (e.g, Richards et al. 2003, Hopkins et al. 2004), which must be included in any automated continuum fitting procedure.”
A Unified, Merger-driven Model of the Origin of Starbursts, Quasars, the Cosmic X-Ray Background, Supermassive Black Holes, and Galaxy Spheroids (2005, methodology): “Observations suggest that the majority of reddened quasars have reddening curves similar to that of the Small Magellanic Cloud (SMC; Hopkins et al. 2004), which has a gas-to-dust ratio lower than the Milky Way by approximately the same factor as its metallicity (Bouchet et al. 1985).”
Active Galactic Nuclei in the Sloan Digital Sky Survey. II. Emission-Line Luminosity Function (2005, methodology): “Based on the general quasar color model (Schneider et al. 2002, 2003; Hopkins et al. 2004), we found g i 0:55 at around z 0:1.”
The Radio-Loud Fraction of Quasars is a Strong Function of Redshift and Optical Luminosity (2006, background): “The RLF rises with increasing (g i), which is the difference between the observed g i and the median g i color of quasars at that redshift, following Hopkins et al. (2004).”
The Sloan Digital Sky Survey Quasar Catalog. IV. Fifth Data Release (2007, methodology): “This SDSS color relation, recently presented in Hopkins et al. (2004), has led to considerable success in assigning photometric redshifts to quasars (e.g., Weinstein et al. 2004 and references therein).”
A Physical Model for the Origin of Quasar Lifetimes (2005, background): “…suggest that the majority of the population of reddened quasars have reddening curves similar to that of the Small Magellenic Cloud (SMC) (Hopkins et al. 2004), which has a gas-to-dust ratio lower than the Milky Way by approximately the same factor as its metallicity (Bouchet et al.…”
THE RADIATIVE EFFICIENCY OF ACCRETION FLOWS IN INDIVIDUAL ACTIVE GALACTIC NUCLEI (2010, methodology): “An analysis of a large Sloan Digital Sky Survey QSO sample (Hopkins et al. 2004) concluded reddening is modest in most sources, with only a small fraction which are reddened significantly (i.e. .”
THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY: THE QUASAR LUMINOSITY FUNCTION FROM DATA RELEASE NINE (2012, methodology): “In this model, individual spectra are extincted using a SMC dust model (Prevot et al. 1984), with values of E(B−V ) distributed exponentially around a peak of 0.03 (e.g., Hopkins et al. 2004).”
The Relation between Quasar and Merging Galaxy Luminosity Functions and the Merger-driven Star Formation History of the Universe (2006, background): “…AB /NH i ¼ 8:47(Z /0:02) ; 10 22 cm2, and a Small Magellanic Cloud–like reddening curve (as suggested by observations for the host galaxies of quasars; Hopkins et al. 2004; Ellison et al. 2005; although the 280 nm cross section is decreased by only 6% if we instead assume a Milky Way–like…”
Dust covering factor, silicate emission, and star formation in luminous QSOs (2007, background): “The ar- row indicates the effect of dust reddening with AV = 2 mag (by assuming a SMC extinction curve, as appropriate for type 1 AGNs, Hopkins et al., 2004), which would be required to account for the observed variations ofλLλ(6.7µm)/λLλ(5100Å).”
Stellar sources of dust in the high-redshift Universe (2009, result): “In both sources, the inferred dust extinction curve is different with respect to any of the extinction curves observed at low z (Hopkins et al. 2004), and it shows a very good agreement with the extinction curve predicted for dustformed in SN ejecta.”
A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. I. Galaxy Mergers and Quasar Activity (2007, result): “As a relatively short phase, such objects constitute only 20%Y40% of the quasar population, similar to that observed (Gregg et al. 2002;White et al. 2003; Richards et al. 2003, 2006a; Hopkins et al. 2004).”
Average extinction curves and relative abundances for quasi-stellar object absorption-line systems at 1 ≤zabs < 2 (2006, methodology): “Hopkins et al. (2004) used composite QSO spectra to show that the extinction towards QSOs is dominated by SMC-like extinction, which they argued was predominantly located atQSO redshifts.”
Accretion states and radio loudness in active galactic nuclei: analogies with X-ray binaries (2006, background): “It follows that we select only sources that are not strongly obscured (see also the discussion of the likely fraction of reddened quasars in the SDSS by Richards et al. 2003; Hopkins et al. 2004).”
THE BARYON OSCILLATION SPECTROSCOPIC SURVEY OF SDSS-III (2012, background): “The goal was a better determination of the distribution of reddenings in intervening absorbers and at the quasar redshift (e.g., Hopkins et al. 2004; Ménard et al. 2008), and investigating reddening as a function of quasar properties.”
Binary Quasars in the Sloan Digital Sky Survey: Evidence for Excess Clustering on Small Scales (2005, background): “Also notice that a long tail in this distribution extends even beyond 2 100 because of outliers from the median color–redshift relation of quasars (Richards et al. 2001a), caused by broad absorption line features (Richards et al. 2003) or reddening (Hopkins et al. 2004).”
An Observational Determination of the Bolometric Quasar Luminosity Function (2006, background): “…above yields a best-fit uncorrelated dispersion component 0.1 dex, consistent with observational estimates of the scatter in band luminosities owing to these effects (e.g., Elvis et al.1994; George et al. 1998; Vanden Berk et al. 2001; Perola et al. 2002; Richards et al. 2003; Hopkins et al. 2004).”
Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations (2012, methodology): “Before combining each of these SEDs with the Bruzual & Charlot (2003) library, to mimic real galaxy emission we reddened the Sy1 template using a Calzetti et al. (2000) law with E(B-V) values between 0 and 0.3 (Hopkins et al. 2004; Merloni et al. 2010) and step of 0.1.”