GOODS-ALMA: 1.1 mm galaxy survey I. Source catalog and optically dark galaxies

Franco, M.; Elbaz, D.; Bethermin, M.; Magnelli, B.; Schreiber, C.; Ciesla, L.; Dickinson, M.; Nagar, N.; Silverman, J.; Daddi, E.; Alexander, D. M.; Wang, T.; Pannella, M.; Le Floc'h, E.; Pope, A.; Giavalisco, M.; Maury, A. J.; Bournaud, F.; Chary, R.; Demarco, R.; Ferguson, H.; Finkelstein, S. L.; Inami, H.; Iono, D.; Juneau, S.; Lagache, G.; Leiton, R.; Lin, L.; Magdis, G.; Messias, H.; Motohara, K.; Mullaney, J.; Okumura, K.; Papovich, C.; Pforr, J.; Rujopakarn, W.; Sargent, M.; Shu, X. und Zhou, L. (2018): GOODS-ALMA: 1.1 mm galaxy survey I. Source catalog and optically dark galaxies. In: Astronomy & Astrophysics, Bd. 620, A152

Abstract

Aims. We present a 69 arcmin(2) ALMA survey at 1.1 mm, GOODS-ALMA, matching the deepest HST-WFC3 H-band part of the GOODS-South field. Methods. We tapered the 0 '' 24 original image with a homogeneous and circular synthesized beam of 0 '' 60 to reduce the number of independent beams - thus reducing the number of purely statistical spurious detections - and optimize the sensitivity to point sources. We extracted a catalog of galaxies purely selected by ALMA and identified sources with and without HST counterparts down to a 5 sigma limiting depth of H = 28.2 AB (HST/WFC3 F160W). Results. ALMA detects 20 sources brighter than 0.7 mJy at 1.1 mm in the 0 '' 60 tapered mosaic (rms sensitivity sigma similar or equal to 0.18 mJy beam(-1)) with a purity greater than 80%. Among these detections, we identify three sources with no HST nor Spitzer-IRAC counterpart, consistent with the expected number of spurious galaxies from the analysis of the inverted image;their definitive status will require additional investigation. We detect additional three sources with HST counterparts either at high significance in the higher resolution map, or with different detection-algorithm parameters ensuring a purity greater than 80%. Hence we identify in total 20 robust detections. Conclusions. Our wide contiguous survey allows us to push further in redshift the blind detection of massive galaxies with ALMA with a median redshift of z = 2.92 and a median stellar mass of M-* = 1.1 x 10(11) M-circle dot. Our sample includes 20% HST-dark galaxies (4 out of 20), all detected in the mid-infrared with Spitzer-IRAC. The near-infrared based photometric redshifts of two of them (z similar to 4.3 and 4.8) suggest that these sources have redshifts z > 4. At least 40% of the ALMA sources host an X-ray AGN, compared to similar to 14% for other galaxies of similar mass and redshift. The wide area of our ALMA survey provides lower values at the bright end of number counts than single-dish telescopes affected by confusion.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 1432-0746
• Sprache: Englisch