Extragalactic Radio Sources and the WMAP Cold Spot
| Autor: | Rudnick, Lawrence, Brown, Shea, Williams, Liliya R. |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Astrophys.J.671:40-44,2007 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1086/522222 |
| Popis: | We detect a dip of 20-45% in the surface brightness and number counts of NVSS sources smoothed to a few degrees at the location of the WMAP cold spot. The dip has structure on scales of approximately 1-10 degrees. Together with independent all-sky wavelet analyses, our results suggest that the dip in extragalactic brightness and number counts and the WMAP cold spot are physically related, i.e., that the coincidence is neither a statistical anomaly nor a WMAP foreground correction problem. If the cold spot does originate from structures at modest redshifts, as we suggest, then there is no remaining need for non-Gaussian processes at the last scattering surface of the CMB to explain the cold spot. The late integrated Sachs-Wolfe effect, already seen statistically for NVSS source counts, can now be seen to operate on a single region. To create the magnitude and angular size of the WMAP cold spot requires a ~140 Mpc radius completely empty void at z<=1 along this line of sight. This is far outside the current expectations of the concordance cosmology, and adds to the anomalies seen in the CMB. Comment: revised version, ApJ, in press |
| Databáze: | arXiv |
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