SPT 0538−50: PHYSICAL CONDITIONS IN THE INTERSTELLAR MEDIUM OF A STRONGLY LENSED DUSTY STAR-FORMING GALAXY AT z = 2.8

• Published in: The Astrophysical Journal
• Main Authors: Bothwell, MS, Aguirre, JE, Chapman, SC, Marrone, DP, Vieira, JD, Ashby, MLN, Aravena, M, Benson, BA, Bock, JJ, Bradford, CM, Brodwin, M, Carlstrom, JE, Crawford, TM, de Breuck, C, Downes, TP, Fassnacht, CD, Gonzalez, AH, Greve, TR, Gullberg, B, Hezaveh, Y, Holder, GP, Holzapfel, WL, Ibar, E, Ivison, R, Kamenetzky, J, Keisler, R, Lupu, RE, Ma, J, Malkan, M, McIntyre, V, Murphy, EJ, Nguyen, HT, Reichardt, CL, Rosenman, M, Spilker, JS, Stalder, B, Stark, AA, Strandet, M, Vernet, J, Weiß, A, Welikala, N
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2013
• Subjects: galaxies: evolution; galaxies: formation; galaxies: high-redshift; galaxies: individual; gravitational lensing: strong; submillimeter: galaxies; astro-ph.CO; Astronomical and Space Sciences; Atomic; Molecular; Nuclear; Particle and Plasma Physics; Physical Chemistry (incl. Structural); Astronomy & Astrophysics; South pole
• Online Access: https://escholarship.org/uc/item/08z24727; https://escholarship.org/content/qt08z24727/qt08z24727.pdf; https://doi.org/10.1088/0004-637x/779/1/67

We present observations of SPT-S J053816-5030.8, a gravitationally lensed dusty star-forming galaxy (DSFG) at z = 2.7817 that was first discovered at millimeter wavelengths by the South Pole Telescope. SPT 0538-50 is typical of the brightest sources found by wide-field millimeter-wavelength surveys, being lensed by an intervening galaxy at moderate redshift (in this instance, at z = 0.441). We present a wide array of multi-wavelength spectroscopic and photometric data on SPT 0538-50, including data from ALMA, Herschel PACS and SPIRE, Hubble, Spitzer, the Very Large Telescope, ATCA, APEX, and the Submillimeter Array. We use high-resolution imaging from the Hubble Space Telescope to de-blend SPT 0538-50, separating DSFG emission from that of the foreground lens. Combined with a source model derived from ALMA imaging (which suggests a magnification factor of 21 ± 4), we derive the intrinsic properties of SPT 0538-50, including the stellar mass, far-IR luminosity, star formation rate, molecular gas mass, and - using molecular line fluxes - the excitation conditions within the interstellar medium. The derived physical properties argue that we are witnessing compact, merger-driven star formation in SPT 0538-50 similar to local starburst galaxies and unlike that seen in some other DSFGs at this epoch. © 2013. The American Astronomical Society. All rights reserved.