We report on extragalactic sources detected in a 455 deg(2) map of the southern sky made with data at a frequency of 148 GHz from the Atacama Cosmology Telescope (ACT) 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15 mJy to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low-redshift X-ray-selected galaxy clusters. Estimates of the radio to millimeter-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (> 50 mJy) 148 GHz selected sample with complete cross-identifications from the Australia Telescope 20 GHz survey, we observe an average steepening of the spectra between 5, 20, and 148 GHz with median spectral indices of alpha(5-20) = -0.07 +/- 0.06, alpha(20-148) = -0.39 +/- 0.04, and alpha(5-148) = -0.20 +/- 0.03. When the measured spectral indices are taken into account, the 148 GHz differential source counts are consistent with previous measurements at 30 GHz in the context of a source count model dominated by radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20 mJy is C-Sync = (2.8 +/- 0.3) x 10(-6) mu K-2.
THE ATACAMA COSMOLOGY TELESCOPE: EXTRAGALACTIC SOURCES AT 148 GHz IN THE 2008 SURVEY / Tobias A., Marriage; Jean Baptiste, Juin; Yen Ting, Lin; Danica, Marsden; Michael R., Nolta; Partridge, Bruce; Peter A. r., Ade; Paula, Aguirre; Mandana, Amiri; John William, Appel; L., Felipe Barrientos; Battistelli, Elia Stefano; John R., Bond; Brown, Ben; Burger, Bryce; Chervenak, Jay; Sudeep, Das; J., Devlin Mark; R., Dicker Simon; W., Bertrand Doriese; Joanna, Dunkley; Rolando, Dunner; Thomas Essinger, Hileman; P., Fisher Ryan; Joseph W., Fowler; Hajian, Amir; Halpern, Mark; Matthew, Hasselfield; Carlos Hernandez, Monteagudo; Gene C., Hilton; Hilton, Matt; Adam D., Hincks; Renee, Hlozek; M., Huffenberger Kevin; David Handel, Hughes; John P., Hughes; Leopoldo, Infante; D., Irwin Kent; Kaul, Madhuri; Jeff, Klein; Kosowsky, Arthur; Judy M., Lau; Michele, Limon; Robert H., Lupton; Krista, Martocci; Mauskopf, Phil; Menanteau, Felipe; Kavilan, Moodley; Moseley, Harvey; Calvin B., Netterfield; Michael D., Niemack; Lyman A., Page; Parker, Lucas; Hernan, Quintana; Beth, Reid; Neelima, Sehgal; D., Sherwin Blake; Jon, Sievers; David N., Spergel; Suzanne T., Staggs; Daniel S., Swetz; Eric R., Switzer; Robert, Thornton; Hy, Trac; Carole, Tucker; Warne, Ryan; Wilson, Grant; Ed, Wollack; Zhao, Yue. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - 731:2(2011), p. 100. [10.1088/0004-637x/731/2/100]
THE ATACAMA COSMOLOGY TELESCOPE: EXTRAGALACTIC SOURCES AT 148 GHz IN THE 2008 SURVEY
BATTISTELLI, Elia Stefano;
2011
Abstract
We report on extragalactic sources detected in a 455 deg(2) map of the southern sky made with data at a frequency of 148 GHz from the Atacama Cosmology Telescope (ACT) 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15 mJy to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low-redshift X-ray-selected galaxy clusters. Estimates of the radio to millimeter-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (> 50 mJy) 148 GHz selected sample with complete cross-identifications from the Australia Telescope 20 GHz survey, we observe an average steepening of the spectra between 5, 20, and 148 GHz with median spectral indices of alpha(5-20) = -0.07 +/- 0.06, alpha(20-148) = -0.39 +/- 0.04, and alpha(5-148) = -0.20 +/- 0.03. When the measured spectral indices are taken into account, the 148 GHz differential source counts are consistent with previous measurements at 30 GHz in the context of a source count model dominated by radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20 mJy is C-Sync = (2.8 +/- 0.3) x 10(-6) mu K-2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
