Spitzer Imaging of Strongly lensed Herschel-selected Dusty Star-forming Galaxies

Autor(en)

Brian Ma, Asantha R. Cooray, J. A. Calanog, H. Nayyeri, N. Timmons, Helmut Dannerbauer

Abstrakt

We present the rest-frame optical spectral energy distribution (SED) and stellar masses of six Herschel-selected gravitationally lensed dusty, star-forming galaxies (DSFGs) at 1 < z < 3. These galaxies were first identified with Herschel/SPIRE imaging data from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). The targets were observed with Spitzer/IRAC at 3.6 and 4.5 μm. Due to the spatial resolution of the IRAC observations at the level of 2″, the lensing features of a background DSFG in the near-infrared are blended with the flux from the foreground lensing galaxy in the IRAC imaging data. We make use of higher resolution Hubble/WFC3 or Keck/NIRC2 Adaptive Optics imaging data to fit light profiles of the foreground lensing galaxy (or galaxies) as a way to model the foreground components, in order to successfully disentangle the foreground lens and background source flux densities in the IRAC images. The flux density measurements at 3.6 and 4.5 μm, once combined with Hubble/WFC3 and Keck/NIRC2 data, provide important constraints on the rest-frame optical SED of the Herschel-selected lensed DSFGs. We model the combined UV- to millimeter-wavelength SEDs to establish the stellar mass, dust mass, star formation rate, visual extinction, and other parameters for each of these Herschel-selected DSFGs. These systems have inferred stellar masses in the range 8 × 10¹⁰ – 4 × 10¹¹ M_⊙ and star formation rates of around 100 M_⊙ yr^‑1. This puts these lensed submillimeter systems well above the SFR-M* relation observed for normal star-forming galaxies at similar redshifts. The high values of SFR inferred for these systems are consistent with a major merger-driven scenario for star formation.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

University of California, Irvine

Journal

The Astrophysical Journal

Band

814

Anzahl der Seiten

13

ISSN

0004-637X

DOI

https://doi.org/10.1088/0004-637X/814/1/17

Publikationsdatum

11-2015

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/spitzer-imaging-of-strongly-lensed-herschelselected-dusty-starforming-galaxies(60b7c0b8-7bc0-4e7e-a14a-598b7377962a).html