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

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

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

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 ∼0.″2. These galaxies were uncovered by the Herschel Lensing Survey 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 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 (R e,dust/R e,star > 1). As a whole, our SMG sample shows a tight anticorrelation between (R e,dust/R e,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 R e,dust/R e,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.

Original languageEnglish (US)
Article number192
JournalAstrophysical Journal
Volume908
Issue number2
DOIs
StatePublished - Feb 20 2021
Externally publishedYes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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