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

Sun, Fengwu; Egami, Eiichi; Rawle, Timothy D.; Walth, Gregory L.; Smail, Ian; Dessauges-Zavadsky, Miroslava; Pérez-González, Pablo G.; Richard, Johan; Combes, Francoise; Ebeling, Harald; Pelló, Roser; Van der Werf, Paul; Altieri, Bruno; Boone, Frédéric; Cava, Antonio; Chapman, Scott C.; Clément, Benjamin; Finoguenov, Alexis; Nakajima, Kimihiko; Rujopakarn, Wiphu; Schaerer, Daniel; Valtchanov, Ivan

Abstract

We present an ALMA 1.3 mm (Band 6) continuum survey of lensed submillimeter galaxies (SMGs) at z = 1.0 to ∼3.2 with an angular resolution of ∼0farcs2. These galaxies were uncovered by the Herschel Lensing Survey and feature exceptionally bright far-infrared continuum emission (Speak ≳ 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 (Re,dust/Re,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 main-sequence SMGs with a low surface brightness at 1.3 mm (≲0.1 mJy arcsec−2), in which the star formation is distributed over the entire galaxy (Re,dust/Re,star > 1). As a whole, our SMG sample shows a tight anticorrelation between (Re,dust/Re,star) and far-infrared surface brightness (ΣIR) over a factor of ≃1000 in ΣIR. This indicates that SMGs with less vigorous star formation (i.e., lower ΣIR) lack central starburst and are likely to retain a broader spatial distribution of star formation over the whole galaxies (i.e., larger Re,dust/Re,star). The same trend can be reproduced with cosmological simulations as a result of central starburst and potentially subsequent "inside-out" quenching, which likely accounts for the emergence of compact quiescent galaxies at z ∼ 2.

Citation

Sun, F., Egami, E., Rawle, T. D., Walth, G. L., Smail, I., Dessauges-Zavadsky, M., …Valtchanov, I. (2021). ALMA 1.3 mm Survey of Lensed Submillimeter Galaxies Selected by Herschel: Discovery of Spatially Extended SMGs and Implications. Astrophysical Journal, 908(2), Article 192. https://doi.org/10.3847/1538-4357/abd6e4

• Journal Article Type: Article
• Acceptance Date: Dec 24, 2020
• Online Publication Date: Feb 24, 2021
• Publication Date: 2021-02
• Deposit Date: May 5, 2021
• Publicly Available Date: Sep 23, 2021
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 908
• Issue: 2
• Article Number: 192
• DOI: https://doi.org/10.3847/1538-4357/abd6e4
• Public URL: https://durham-repository.worktribe.com/output/1275965