The QUaD Galactic Plane Survey. I. Maps and Analysis of Diffuse Emission

October 2010 • 2010ApJ...722.1057C

Authors • Culverhouse, T. • Ade, P. • Bock, J. • Bowden, M. • Brown, M. L. • Cahill, G. • Castro, P. G. • Church, S. E. • Friedman, R. • Ganga, K. • Gear, W. K. • Gupta, S. • Hinderks, J. R. • Kovac, J. • Lange, A. E. • Leitch, E. • Melhuish, S. J. • Memari, Y. • Murphy, J. A. • Orlando, A. • Schwarz, R. • O'Sullivan, C. • Piccirillo, L. • Pryke, C. • Rajguru, N. • Rusholme, B. • Taylor, A. N. • Thompson, K. L. • Turner, A. H. • Wu, E. Y. S. • Zemcov, M. • QUaD Collaboration

Abstract • We present a survey of ~800 deg² of the galactic plane observed with the QUaD telescope. The primary products of the survey are maps of Stokes I, Q, and U parameters at 100 and 150 GHz, with spatial resolution of 5' and 3farcm5, respectively. Two regions are covered, spanning approximately 245°-295° and 315°-5° in the galactic longitude l and -4° < b < +4° in the galactic latitude b. At 0fdg02 square pixel size, the median sensitivity is 74 and 107 kJy sr^-1 at 100 GHz and 150 GHz respectively in I, and 98 and 120 kJy sr^-1 for Q and U. In total intensity, we find an average spectral index of α = 2.35 ± 0.01(stat) ± 0.02(sys) for |b| <= 1°, indicative of emission components other than thermal dust. A comparison to published dust, synchrotron, and free-free models implies an excess of emission in the 100 GHz QUaD band, while better agreement is found at 150 GHz. A smaller excess is observed when comparing QUaD 100 GHz data to the WMAP five-year W band; in this case, the excess is likely due to the wider bandwidth of QUaD. Combining the QUaD and WMAP data, a two-component spectral fit to the inner galactic plane (|b| <= 1°) yields mean spectral indices of α _s = -0.32 ± 0.03 and α _d = 2.84 ± 0.03; the former is interpreted as a combination of the spectral indices of synchrotron, free-free, and dust, while the second is largely attributed to the thermal dust continuum. In the same galactic latitude range, the polarization data show a high degree of alignment perpendicular to the expected galactic magnetic field direction, and exhibit mean polarization fraction 1.38 ± 0.08(stat) ± 0.1(sys)% at 100 GHz and 1.70 ± 0.06(stat) ± 0.1(sys)% at 150 GHz. We find agreement in polarization fraction between QUaD 100 GHz and the WMAP W band, the latter giving 1.1% ± 0.4%.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2010ApJ...722.1057C
• PDF https://iopscience.iop.org/article/10.1088/0004-637X/722/2/1057/pdf
• PDF https://stacks.iop.org/0004-637X/722/1057/pdf
• PREPRINT http://arxiv.org/abs/1001.1333
• ELECTR https://doi.org/10.1088%2F0004-637X%2F722%2F2%2F1057