Dust reddened quasars in first and UKIDSS: Beyond the tip of the iceberg

Eilat Glikman, Tanya Urrutia, Mark Lacy, S. G. Djorgovski, Meg Urry, Scott Croom, Donald P. Schneider, Ashish Mahabal, Matthew Graham, Jian Ge

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Abstract

We present the results of a pilot survey to find dust-reddened quasars by matching the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio catalog to the UKIDSS near-infrared survey and using optical data from Sloan Digital Sky Survey to select objects with very red colors. The deep K-band limit provided by UKIDSS allows for finding more heavily reddened quasars at higher redshifts as compared with previous work using FIRST and Two Micron All Sky Survey (2MASS). We selected 87 candidates with K ≤ 17.0 from the UKIDSS Large Area Survey (LAS) First Data Release (DR1), which covers 190 deg2. These candidates reach up to ∼1.5 mag below the 2MASS limit and obey the color criteria developed to identify dust-reddened quasars. We have obtained 61 spectroscopic observations in the optical and/or near-infrared, as well as classifications in the literature, and have identified 14 reddened quasars with E(B-V) > 0.1, including 3 at z > 2. We study the infrared properties of the sample using photometry from the Wide-Field Infrared Survey Explorer and find that infrared colors improve the efficiency of red quasar selection, removing many contaminants in an infrared-to-optical color-selected sample alone. The highest-redshift quasars (z ≳ 2) are only moderately reddened, with E(B-V) ∼ 0.2-0.3. We find that the surface density of red quasars rises sharply with faintness, comprising up to 17% of blue quasars at the same apparent K-band flux limit. We estimate that to reach more heavily reddened quasars (i.e., E(B-V) ≳ 0.5) at z > 2 and a depth of K = 17, we would need to survey at least ∼2.5 times more area.

Original languageEnglish (US)
Article number127
JournalAstrophysical Journal
Volume778
Issue number2
DOIs
StatePublished - Dec 1 2013

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quasars
dust
radio
color
near infrared
extremely high frequencies
sky
Wide-field Infrared Survey Explorer
catalogs
contaminants
photometry
pollutant
estimates

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Glikman, E., Urrutia, T., Lacy, M., Djorgovski, S. G., Urry, M., Croom, S., ... Ge, J. (2013). Dust reddened quasars in first and UKIDSS: Beyond the tip of the iceberg. Astrophysical Journal, 778(2), [127]. https://doi.org/10.1088/0004-637X/778/2/127
Glikman, Eilat ; Urrutia, Tanya ; Lacy, Mark ; Djorgovski, S. G. ; Urry, Meg ; Croom, Scott ; Schneider, Donald P. ; Mahabal, Ashish ; Graham, Matthew ; Ge, Jian. / Dust reddened quasars in first and UKIDSS : Beyond the tip of the iceberg. In: Astrophysical Journal. 2013 ; Vol. 778, No. 2.
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Glikman, E, Urrutia, T, Lacy, M, Djorgovski, SG, Urry, M, Croom, S, Schneider, DP, Mahabal, A, Graham, M & Ge, J 2013, 'Dust reddened quasars in first and UKIDSS: Beyond the tip of the iceberg', Astrophysical Journal, vol. 778, no. 2, 127. https://doi.org/10.1088/0004-637X/778/2/127

Dust reddened quasars in first and UKIDSS : Beyond the tip of the iceberg. / Glikman, Eilat; Urrutia, Tanya; Lacy, Mark; Djorgovski, S. G.; Urry, Meg; Croom, Scott; Schneider, Donald P.; Mahabal, Ashish; Graham, Matthew; Ge, Jian.

In: Astrophysical Journal, Vol. 778, No. 2, 127, 01.12.2013.

Research output: Contribution to journalArticle

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AU - Glikman, Eilat

AU - Urrutia, Tanya

AU - Lacy, Mark

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AU - Urry, Meg

AU - Croom, Scott

AU - Schneider, Donald P.

AU - Mahabal, Ashish

AU - Graham, Matthew

AU - Ge, Jian

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Glikman E, Urrutia T, Lacy M, Djorgovski SG, Urry M, Croom S et al. Dust reddened quasars in first and UKIDSS: Beyond the tip of the iceberg. Astrophysical Journal. 2013 Dec 1;778(2). 127. https://doi.org/10.1088/0004-637X/778/2/127