Pontificia Universidad Católica de Chile Pontificia Universidad Católica de Chile
Aguirre P., Lindner R.R., Baker A.J., Bond J.R., Dünner R., Galaz G., Gallardo P., Hilton M., Hughes J.P., Infante L., Lima M., Menten K.M., Sievers J., Weiss A. and Wollack E.J. (2018)

The LABOCA/ACT Survey of Clusters at All Redshifts: Multiwavelength Analysis of Background Submillimeter Galaxies

Revista : Astrophysical Journal
Volumen : 855
Número : 1
Páginas : 30pp
Tipo de publicación : ISI Ir a publicación


We present a multi-wavelength analysis of 48 submillimeter galaxies (SMGs) detected in the LABOCA/ACT Survey of Clusters at All Redshifts, LASCAR, which acquired new 870 um and ATCA 2.1 GHz observations of ten galaxy clusters detected through their Sunyaev-Zel’dovich effect (SZE) signal by the Atacama Cosmology Telescope. Far-infrared observations were also conducted with the PACS (100/160 um) and SPIRE (250/350/500 um) instruments on {it Herschel} for sample subsets of five and six clusters. LASCAR 870 micron, maps were reduced using a multi-scale iterative pipeline that removes the SZE increment signal, yielding point-source sensitivities of $sigmasim2rm{,mJy,beam}^{-1}$. We detect in total 49 sources at the $4sigma$ level, and conduct a detailed multi-wavelength analysis considering our new radio and far-IR observations plus existing near-IR and optical data. One source is identified as a foreground galaxy, 28 SMGs are matched to single radio sources, 4 have double radio counterparts, and 16 are undetected at 2.1 GHz but tentatively associated in some cases to near-IR/optical sources. We estimate photometric redshifts for 34 sources with secure (25) and tentative (9) matches at different wavelengths, obtaining a median $z=2.8^{+2.1}_{-1.7}$. Compared to previous results for single-dish surveys, our redshift distribution has a comparatively larger fraction of sources at z>3 and the high-redshift tail is more extended. This is consistent with millimeter spectroscopic confirmation of a growing number of high-z SMGs and relevant for testing of cosmological models. Analytical lens modeling is applied to estimate magnification factors for 42 SMGs at cluster-centric radii >1.2′; with the demagnified flux densities and source-plane areas, we obtain integral number counts that agree with previous submillimeter surveys.