SIGNIFICANT FOREGROUND UNRELATED NON-ACOUSTIC ANISOTROPY ON THE 1 DEGREE SCALE IN WILKINSON MICROWAVE ANISOTROPY PROBE 5-YEAR OBSERVATIONS

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/708/1/375· OSTI ID:21392467

Bizhu, Jiang; Shuangnan, Zhang ^[1]; Lieu, Richard ^[2]; Wakker, Bart ^[3]

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1. Physics Department and Center for Astrophysics, Tsinghua University, Beijing 100084 (China)
2. Department of Physics, University of Alabama, Huntsville, AL 35899 (United States)
3. Department of Astronomy, University of Wisconsin, 475 N. Charter St., Madison, WI 53706 (United States)

The spectral variation of the cosmic microwave background (CMB) as observed by WMAP was tested using foreground reduced WMAP5 data, by producing subtraction maps at the 1 deg. angular resolution between the two cosmological bands of V and W, for masked sky areas that avoid the Galactic disk. The resulting V - W map revealed a non-acoustic signal over and above the WMAP5 pixel noise, with two main properties. First, it possesses quadrupole power at the approx1 muK level which may be attributed to foreground residuals. Second, it fluctuates also at all values of l> 2, especially on the 1 deg. scale (200 approx< l approx< 300). The behavior is random and symmetrical about zero temperature with an rms approx7 muK, or 10% of the maximum CMB anisotropy, which would require a 'cosmic conspiracy' among the foreground components if it is a consequence of their existence. Both anomalies must be properly diagnosed and corrected if 'precision' cosmology is the claim. The second anomaly is, however, more interesting because it opens the question on whether the CMB anisotropy genuinely represents primordial density seeds.

• OSTI ID: 21392467
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 708; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
COSMOLOGY
DATA ANALYSIS
ELECTROMAGNETIC RADIATION
MICROWAVE RADIATION
RADIATIONS
RANDOMNESS
RELICT RADIATION
SIGNALS