Ma, Jingzhe and Brown, Arianna and Cooray, Asantha and Nayyeri, Hooshang and Messias, Hugo and Timmons, Nicholas and Staguhn, Johannes and Temi, Pasquale and Dowell, C. Darren and Wardlow, Julie and Fadda, Dario and Kovacs, Attila and Riechers, Dominik and Oteo, Ivan and Wilson, Derek and Perez-Fournon, Ismael (2018) SOFIA/HAWC+ Detection of a Gravitationally Lensed Starburst Galaxy at z = 1.03. The Astrophysical Journal, 864 (1): 60. ISSN 0004-637X
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Abstract
We present the detection at 89 μm (observed frame) of the Herschel-selected gravitationally lensed starburst galaxy HATLAS J1429-0028 (also known as G15v2.19) in 15 minutes with the High-resolution Airborne Wideband Camera-plus (HAWC+) onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). The spectacular lensing system consists of an edge-on foreground disk galaxy at z = 0.22 and a nearly complete Einstein ring of an intrinsic ultra-luminous infrared (IR) galaxy at z = 1.03. Is this high IR luminosity powered by pure star formation (SF) or also an active galactic nucleus (AGN)? Previous nebular line diagnostics indicate that it is star formation dominated. We perform a 27-band multiwavelength spectral energy distribution (SED) modeling including the new SOFIA/HAWC+ data to constrain the fractional AGN contribution to the total IR luminosity. The AGN fraction in the IR turns out to be negligible. In addition, J1429-0028 serves as a testbed for comparing SED results from different models/templates and SED codes (MAGPHYS, SED3FIT, and CIGALE). We stress that star formation history is the dominant source of uncertainty in the derived stellar mass (as high as a factor of ∼10) even in the case of extensive photometric coverage. Furthermore, the detection of a source at z ∼ 1 with SOFIA/HAWC+ demonstrates the potential of utilizing this facility for distant galaxy studies including the decomposition of SF/AGN components, which cannot be accomplished with other current facilities.