THE Q/U IMAGING EXPERIMENT

POLARIZATION MEASUREMENTS of RADIO SOURCES at 43 and 95 GHz

K. M. Huffenberger, D. Araujo, C. Bischoff, I. Buder, Y. Chinone, K. Cleary, A. Kusaka, R. Monsalve, S. K. Nss, L. B. Newburgh, R. Reeves, T. M. Ruud, I. K. Wehus, J. T L Zwart, C. Dickinson, H. K. Eriksen, T. Gaier, Joshua Gundersen, M. Hasegawa, M. Hazumi & 6 others A. D. Miller, S. J E Radford, A. C S Readhead, S. T. Staggs, O. Tajima, K. L. Thompson

Research output: Contribution to journalArticle

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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 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼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.

Original languageEnglish (US)
Article number112
JournalAstrophysical Journal
Volume806
Issue number1
DOIs
StatePublished - Jun 10 2015

Fingerprint

polarization
experiment
radio
extragalactic radio sources
radio galaxies
linear polarization
signal-to-noise ratio
catalogs
confidence
signal to noise ratios
flux density
telescopes
microwaves

Keywords

  • cosmic background radiation
  • galaxies: active
  • galaxies: individual (Cen A, Pict A)
  • methods: statistical
  • polarizat

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Huffenberger, K. M., Araujo, D., Bischoff, C., Buder, I., Chinone, Y., Cleary, K., ... Thompson, K. L. (2015). THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS of RADIO SOURCES at 43 and 95 GHz. Astrophysical Journal, 806(1), [112]. https://doi.org/10.1088/0004-637X/806/1/112

THE Q/U IMAGING EXPERIMENT : POLARIZATION MEASUREMENTS of RADIO SOURCES at 43 and 95 GHz. / Huffenberger, K. M.; Araujo, D.; Bischoff, C.; Buder, I.; Chinone, Y.; Cleary, K.; Kusaka, A.; Monsalve, R.; Nss, S. K.; Newburgh, L. B.; Reeves, R.; Ruud, T. M.; Wehus, I. K.; Zwart, J. T L; Dickinson, C.; Eriksen, H. K.; Gaier, T.; Gundersen, Joshua; Hasegawa, M.; Hazumi, M.; Miller, A. D.; Radford, S. J E; Readhead, A. C S; Staggs, S. T.; Tajima, O.; Thompson, K. L.

In: Astrophysical Journal, Vol. 806, No. 1, 112, 10.06.2015.

Research output: Contribution to journalArticle

Huffenberger, KM, Araujo, D, Bischoff, C, Buder, I, Chinone, Y, Cleary, K, Kusaka, A, Monsalve, R, Nss, SK, Newburgh, LB, Reeves, R, Ruud, TM, Wehus, IK, Zwart, JTL, Dickinson, C, Eriksen, HK, Gaier, T, Gundersen, J, Hasegawa, M, Hazumi, M, Miller, AD, Radford, SJE, Readhead, ACS, Staggs, ST, Tajima, O & Thompson, KL 2015, 'THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS of RADIO SOURCES at 43 and 95 GHz', Astrophysical Journal, vol. 806, no. 1, 112. https://doi.org/10.1088/0004-637X/806/1/112
Huffenberger KM, Araujo D, Bischoff C, Buder I, Chinone Y, Cleary K et al. THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS of RADIO SOURCES at 43 and 95 GHz. Astrophysical Journal. 2015 Jun 10;806(1). 112. https://doi.org/10.1088/0004-637X/806/1/112
Huffenberger, K. M. ; Araujo, D. ; Bischoff, C. ; Buder, I. ; Chinone, Y. ; Cleary, K. ; Kusaka, A. ; Monsalve, R. ; Nss, S. K. ; Newburgh, L. B. ; Reeves, R. ; Ruud, T. M. ; Wehus, I. K. ; Zwart, J. T L ; Dickinson, C. ; Eriksen, H. K. ; Gaier, T. ; Gundersen, Joshua ; Hasegawa, M. ; Hazumi, M. ; Miller, A. D. ; Radford, S. J E ; Readhead, A. C S ; Staggs, S. T. ; Tajima, O. ; Thompson, K. L. / THE Q/U IMAGING EXPERIMENT : POLARIZATION MEASUREMENTS of RADIO SOURCES at 43 and 95 GHz. In: Astrophysical Journal. 2015 ; Vol. 806, No. 1.
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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 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼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.",
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T2 - POLARIZATION MEASUREMENTS of RADIO SOURCES at 43 and 95 GHz

AU - Huffenberger, K. M.

AU - Araujo, D.

AU - Bischoff, C.

AU - Buder, I.

AU - Chinone, Y.

AU - Cleary, K.

AU - Kusaka, A.

AU - Monsalve, R.

AU - Nss, S. K.

AU - Newburgh, L. B.

AU - Reeves, R.

AU - Ruud, T. M.

AU - Wehus, I. K.

AU - Zwart, J. T L

AU - Dickinson, C.

AU - Eriksen, H. K.

AU - Gaier, T.

AU - Gundersen, Joshua

AU - Hasegawa, M.

AU - Hazumi, M.

AU - Miller, A. D.

AU - Radford, S. J E

AU - Readhead, A. C S

AU - Staggs, S. T.

AU - Tajima, O.

AU - Thompson, K. L.

PY - 2015/6/10

Y1 - 2015/6/10

N2 - 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 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼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.

AB - 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 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼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.

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KW - galaxies: active

KW - galaxies: individual (Cen A, Pict A)

KW - methods: statistical

KW - polarizat

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