ALMA 1.3 mm Survey of Lensed Submillimeter Galaxies (SMGs) Selected by Herschel: Discovery of Spatially Extended SMGs and Implications

Abstract

We present an ALMA 1.3 mm (Band 6) continuum survey of lensed submillimeter galaxies (SMGs) at z = 1.0 ∼ 3.2 with an angular resolution of ∼ 0. 2. These galaxies were uncovered by the Herschel Lensing Survey (HLS), and feature exceptionally bright far-infrared continuum emission (S peak 90 mJy) owing to their lensing magnification. We detect 29 sources in 20 fields of massive galaxy clusters with ALMA. Using both the Spitzer/IRAC (3.6/4.5 µm) and ALMA data, we have successfully modeled the surface brightness profiles of 26 sources in the rest-frame near-and far-infrared. Similar to previous studies, we find the median dust-to-stellar continuum size ratio to be small (R e,dust /R e,star = 0.38±0.14) for the observed SMGs, indicating that star formation is centrally concentrated. This is, however, not the case for two spatially extended mainsequence SMGs with a low surface brightness at 1.3 mm ( 0.1 mJy arcsec −2 ), in which the star formation