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Seven-year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic Foreground Emission

Gold, B. and Odegard, N. and Weiland, J. L. and Hill, R. S. and Kogut, A. and Bennett, C. L. and Hinshaw, G. and Chen, X. and Dunkley, J. and Halpern, M. and Jarosik, N. and Komatsu, E. and Larson, D. and Limon, M. and Meyer, S. S. and Nolta, M. R. and Page, L. and Smith, K. M. and Spergel, D. N. and Tucker, G. S. and Wollack, E. and Wright, E. L. (2011) Seven-year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic Foreground Emission. Astrophysical Journal Supplement Series, 192 (2). Art. No. 15. ISSN 0067-0049.

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We present updated estimates of Galactic foreground emission using seven years of WMAP data. Using the power spectrum of differences between multi-frequency template-cleaned maps, we find no evidence for foreground contamination outside of the updated (KQ85y7) foreground mask.We place a 15μK upper bound on rms foreground contamination in the cleaned maps used for cosmological analysis. Further, the cleaning process requires only three power-law foregrounds outside of the mask. We find no evidence for polarized foregrounds beyond those from soft (steep-spectrum) synchrotron and thermal dust emission; in particular we find no indication in the polarization data of an extra “haze” of hard synchrotron emission from energetic electrons near the Galactic center. We provide an updated map of the cosmic microwave background (CMB) using the internal linear combination method, updated foreground masks, and updates to point source catalogs using two different techniques. With additional years of data, we now detect 471 point sources using a five-band technique and 417 sources using a three-band CMB-free technique. In total there are 62 newly detected point sources, a 12% increase over the five-year release. Also new are tests of theMarkov chain Monte Carlo foreground fitting procedure against systematics in the time-stream data, and tests against the observed beam asymmetry. Within a few degrees of the Galactic plane, the behavior in total intensity of low-frequency foregrounds is complicated and not completely understood. WMAP data show a rapidly steepening spectrum from 20 to 40 GHz, which may be due to emission from spinning dust grains, steepening synchrotron, or other effects. Comparisons are made to a 1 deg 408 MHz map (Haslam et al.) and the 11 deg ARCADE 2 data (Singal et al.).We find that spinning dust or steepening synchrotron models fit the combination of WMAP and 408 MHz data equally well. ARCADE data appear inconsistent with the steepening synchrotron model and consistent with the spinning dust model, though some discrepancies remain regarding the relative strength of spinning dust emission. More high-resolution data in the 10–40 GHz range would shed much light on these issues.

Item Type:Article
Related URLs:
URLURL TypeDescription
Bennett, C. L.0000-0001-8839-7206
Chen, X.0000-0001-9152-6224
Halpern, M.0000-0002-1760-0868
Komatsu, E.0000-0002-0136-2404
Limon, M.0000-0002-5900-2698
Page, L.0000-0002-9828-3525
Spergel, D. N.0000-0002-5151-0006
Tucker, G. S.0000-0002-6954-6947
Wollack, E.0000-0002-7567-4451
Wright, E. L.0000-0001-5058-1593
Additional Information:© 2011 The American Astronomical Society. Received 2010 January 26; accepted 2010 May 15; published 2011 January 11. WMAP is the result of a partnership between Princeton University and NASA’s Goddard Space Flight Center. Scientific guidance is provided by the WMAP Science Team. The WMAP mission is made possible by the support of the Science Mission Directorate Office at NASA Headquarters. This research was additionally supported by NASA grants NNG05GE76G, NNX07AL75G S01, LTSA03-000-0090, ATPNNG04GK55G, and ADP03-0000-092. This research has made use of NASA’s Astrophysics Data System Bibliographic Services. We acknowledge use of the HEALPix, CAMB, and CMBFAST packages.
Funding AgencyGrant Number
Subject Keywords:cosmic background radiation; cosmology: observations; diffuse radiation; Galaxy: halo; Galaxy: structure; ISM: structure
Issue or Number:2
Classification Code:PACS: 98.35.Gi; 98.70.Vc; 98.35.Jk; 95.85.Bh; 95.30.Gv
Record Number:CaltechAUTHORS:20110302-102609457
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Official Citation:B. Gold et al. 2011 ApJS 192 15 doi: 10.1088/0067-0049/192/2/15
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22603
Deposited By: Ruth Sustaita
Deposited On:03 Mar 2011 03:52
Last Modified:09 Mar 2020 13:19

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