Colors of 2625 Quasars at 0 < z < 5 Measured in the Sloan Digital Sky Survey Photometric System

DSpace/Manakin Repository

Colors of 2625 Quasars at 0 < z < 5 Measured in the Sloan Digital Sky Survey Photometric System

Citable link to this page


Title: Colors of 2625 Quasars at 0 < z < 5 Measured in the Sloan Digital Sky Survey Photometric System
Author: Richards, Gordon T.; Fan, Xiaohui; Schneider, Donald P.; Vanden Berk, Daniel E.; Strauss, Michael A.; York, Donald G.; Anderson, Jr., John E.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Bernardi, Mariangela; Briggs, John W.; Brinkmann, J.; Brunner, Robert; Burles, Scott; Carey, Larry; Castander, Francisco J.; Connolly, A. J.; Crocker, J. H.; Csabai, István; Doi, Mamoru; Finkbeiner, Douglas; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gunn, James E.; Hindsley, Robert B.; Ivezic, Zeljko; Kent, Stephen; Knapp, G. R.; Lamb, D. Q.; Leger, R. French ; Long, Daniel C.; Loveday, Jon; Lupton, Robert H.; McKay, Timothy A.; Meiksin, Avery; Merrelli, Aronne; Munn, Jeffrey A.; Newberg, Heidi Jo; Newcomb, Matt; Nichol, R. C.; Owen, Russell; Pier, Jeffrey R.; Pope, Adrian; Richmond, Michael W.; Rockosi, Constance M.; Schlegel, David J.; Siegmund, Walter A.; Smee, Stephen; Snir, Yehuda; Stoughton, Chris; Stubbs, Christopher William; SubbaRao, Mark; Szalay, Alexander S.; Szokoly, Gyula P.; Tremonti, Christy; Uomoto, Alan; Waddell, Patrick; Yanny, Brian; Zheng, Wei

Note: Order does not necessarily reflect citation order of authors.

Citation: Richards, Gordon T., Xiaohui Fan, Donald P. Schneider, Daniel E. Vanden Berk, Michael A. Strauss, Donald G. York, John E. Anderson, Jr., et al. 2001. “Colors of 2625 Quasars at 0 < z < 5 Measured in the Sloan Digital Sky Survey Photometric System.” The Astronomical Journal 121 (5) (May): 2308–2330. doi:10.1086/320392.
Full Text & Related Files:
Abstract: 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: 1759 quasars found during SDSS spectroscopic commissioning and SDSS follow-up observations on other telescopes, 50 matches to FIRST quasars, 573 matches to quasars from the NASA Extragalactic Database, and 243 quasars from two or more of these sources. The quasars are distributed in a 2fdg5 wide stripe centered on the celestial equator covering ~529 deg2. Positions (accurate to 0farcs2) and SDSS magnitudes are given for the 898 quasars known prior to SDSS spectroscopic commissioning. New SDSS quasars, which range in brightness from i* = 15.39 to the photometric magnitude limit of the survey, represent an increase of over 200% in the number of known quasars in this area of the sky. The ensemble average of the observed colors of quasars in the SDSS passbands are well represented by a power-law continuum with αν = -0.5 (fν ∝ να) and are close to those predicted by previous simulations. However, the contributions of the "small blue (or λ3000) bump" and other strong emission lines have a significant effect upon the colors. The color-redshift relation exhibits considerable structure, which may be of use in determining photometric redshifts for quasars from their colors alone. The range of colors at a given redshift can generally be accounted for by a range in the optical spectral index with a distribution αν = -0.5 ± 0.65 (95% confidence), but there is a red tail in the distribution. This tail may be a sign of internal reddening, especially since fainter objects at a given redshift tend to exhibit redder colors than the average. Finally, we show that there is a continuum of properties between quasars and Seyfert galaxies, and we test the validity of the traditional dividing line (MB = -23) between the two classes of active galactic nuclei.
Published Version: doi:10.1086/320392
Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at
Citable link to this page:
Downloads of this work:

Show full Dublin Core record

This item appears in the following Collection(s)


Search DASH

Advanced Search