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Author(s): Huffenberger, KM; Araujo, D; Bischoff, C; Buder, I; Chinone, Y; et al

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Abstract: We present polarization measurements of extragalactic radio sources observed during the cosmic microwave background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are similar to 480 such sources within QUIET’s four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30-40 mJy per Stokes parameter. At signal-to-noise ratio >3 significance, we detect linear polarization for seven sources in Q-band and six in W-band; only 1.3 +/- 1.1 detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization measurements of the same sources from the literature. For the four sources with WMAP and Planck intensity measurements >1 Jy, the polarization fractions are above 1% in both QUIET bands. At high significance, we compute polarization fractions as much as 10%-20% for some sources, but the effects of source variability may cut that level in half for contemporaneous comparisons. Our results indicate that simple models-ones that scale a fixed polarization fraction with frequency-are inadequate to model the behavior of these sources and their contributions to polarization maps.
Publication Date: 10-Jun-2015
Electronic Publication Date: 10-Jun-2015
Citation: Huffenberger, KM, Araujo, D, Bischoff, C, Buder, I, Chinone, Y, Cleary, K, Kusaka, A, Monsalve, R, Naess, SK, Newburgh, LB, Reeves, R, Ruud, TM, Wehus, IK, Zwart, JTL, Dickinson, C, Eriksen, HK, Gaier, T, Gundersen, JO, Hasegawa, M, Hazumi, M, Miller, AD, Radford, SJE, Readhead, ACS, Staggs, ST, Tajima, O, Thompson, KL, Collaboration, QUIET. (2015). THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF RADIO SOURCES AT 43 AND 95 GHz. ASTROPHYSICAL JOURNAL, 806 (10.1088/0004-637X/806/1/112
DOI: doi:10.1088/0004-637X/806/1/112
ISSN: 0004-637X
EISSN: 1538-4357
Type of Material: Journal Article
Journal/Proceeding Title: ASTROPHYSICAL JOURNAL
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

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