ALMA Deep Field in SSA22: Source Catalog and Number Counts

Abstract

We present results from a deep 2′×3′ (comoving scale of 3.7 Mpc×5.5 Mpc at z = 3) survey at 1.1mm, taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in the SSA22 field. We observe the core region of a z = 3.09 protocluster, achieving a typical rms sensitivity of 60 μJy beam −1 at a spatial resolution of 0 7. We detect 18 robust ALMA sources at a signal-to-noise ratio (S/N)>5. Comparison between the ALMA map and a 1.1mm map, taken with the AzTEC camera on the Atacama Submillimeter Telescope Experiment (ASTE), indicates that three submillimeter sources discovered by the AzTEC/ASTE survey are resolved into eight individual submillimeter galaxies (SMGs) by ALMA. At least 10 of our 18 ALMA SMGs have spectroscopic redshifts of z;3.09, placing them in the protocluster. This shows that a number of dusty starburst galaxies are forming simultaneously in the core of the protocluster. The nine brightest ALMA SMGs with S/N>10 have a median intrinsic angular size of  -+ 0. 32 0.06 0.13 ( -+ 2.4 0.4 1.0 physical kpc at z = 3.09), which is consistent with previous size measurements of SMGs in other fields. As expected, the source counts show a possible excess compared to the counts in the general fields at S 1.1mm 1.0 mJy, due to the protocluster. Our contiguous mm mapping highlights the importance of large-scale structures on the formation of dusty starburst galaxies.

Deep Submillimeter and Radio Observations in the SSA22 Field. I. Powering Sources and the Lyα Escape Fraction of Lyα Blobs

“…[C II] emission has also been detected in ALMA-LAB1b with a secured redshift of 3.0993 ± 0.0004 (Umehata et al 2017b). …”

“…21 The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Matsuda et al 2017, in preparation). Another two LABs, LAB12 and LAB14, had been covered by a deep field in SSA22 (Umehata et al 2015(Umehata et al , 2017b in band 6 with a central frequency of 263 GHz. The data were reduced with the CASA package in a standard manner (for details, see Umehata et al 2017b andY.…”

“…Another two LABs, LAB12 and LAB14, had been covered by a deep field in SSA22 (Umehata et al 2015(Umehata et al , 2017b in band 6 with a central frequency of 263 GHz. The data were reduced with the CASA package in a standard manner (for details, see Umehata et al 2017b andY. Matsuda et al 2017, in preparation).…”

Automated Mining of the ALMA Archive in the COSMOS Field (A3COSMOS). I. Robust ALMA Continuum Photometry Catalogs and Stellar Mass and Star Formation Properties for ∼700 Galaxies at z = 0.5–6

“…3, we compare the depth and areal coverage of the ALMA archival data in COSMOS at ALMA Band 6 and 7 to the selected existing contiguous ALMA continuum deep fields: Aravena et al (2016; see also Walter et al 2016); Dunlop et al (2017); and Franco et al (2018;PI: D. Elbaz). Other ALMA deep fields (e.g., Hatsukade et al 2016;Umehata et al 2017) have similar properties and are therefore not shown. We compute the depth of each ALMA image by converting its rms noise to an equivalent flux at observed-frame 1.1 mm assuming a modified blackbody with β = 1.8.…”

A Radio-to-mm Census of Star-forming Galaxies in Protocluster 4C23.56 at Z = 2.5: Gas Mass and Its Fraction Revealed with ALMA

“…This suggests that the CO(3-2) (or dust) detection of the galaxies depends on (but not necessarily) the large-scale structure. Umehata et al (2015Umehata et al ( , 2017 argued that there is a concentration of the 1.1 mm continuum sources in the node of protocluster SSA22, where filamentary structures meet. If it also applies to our case, the detection in the region of highest surface densitymay be mirroring the preferential place of gas detection withincertain large structures of the protocluster, e.g., projected filaments or the node, where the gas is infalling or being accreted.…”