THE SCUBA-2 COSMOLOGY LEGACY SURVEY: ALMA RESOLVES THE REST-FRAME FAR-INFRARED EMISSION OF SUB-MILLIMETER GALAXIES

By J. Simpson, I. Smail, A. M. Swinbank, O. Almaini, A. Blain, M. Bremer, S. Chapman, Chian-Chou Chen, Christopher J. Conselice, K. Coppin and 34 more. Astrophysical Journal, 2014

153 citations recorded by the source corpus.

We present high-resolution (0.″3) Atacama Large Millimeter Array 870 μm imaging of 52 sub-millimeter galaxies (SMGs) in the Ultra Deep Survey field to investigate the size and morphology of the sub-millimeter (sub-mm) emission on 2–10 kpc scales. We derive a median intrinsic angular size of FWHM = 0.″30 ± 0.″04 for the 23 SMGs in the sample detected at a signal-to-noise ratio (S/N) >10. Using the photometric redshifts of the SMGs we show that this corresponds to a median physical half-light diameter of 2.4 ± 0.2 kpc. A stacking analysis of the SMGs detected at S/N <10 shows they have sizes consistent with the 870 μm bright SMGs in the sample. We compare our results to the sizes of SMGs derived from other multi-wavelength studies, and show that the rest-frame ∼250 μm sizes of SMGs are consistent with studies of resolved 12CO (J = 3–2 to 7–6) emission lines, but that sizes derived from 1.4 GHz imaging appear to be approximately two times larger on average, which we attribute to cosmic ray diffusion. The rest-frame optical sizes of SMGs are around four times larger than the sub-millimeter sizes, indicating that the star formation in these galaxies is compact relative to the pre-existing stellar distribution. The size of the starburst region in SMGs is consistent with the majority of the star formation occurring in a central region, a few kiloparsecs in extent, with a median star formation rate surface density of 90 ± 30 M☉ yr−1 kpc−2, which may suggest that we are witnessing an intense period of bulge growth in these galaxies.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c5392492c5d962af6a691ff89c432f1b1cdab6d2

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In Astronomy and Astrophysics

1. L. Hernquist
2. P. Hopkins
3. P. V. van Dokkum
4. M. Franx
5. D. M. Alexander
6. D. Narayanan
7. Mark Dickinson
8. J. Dunlop

In Nuclear and High Energy Physics

1. R. Ivison
2. I. Smail
3. D. M. Alexander
4. S. Chapman
5. A. Blain
6. F. Walter
7. E. Daddi
8. D. Narayanan

Citations in the corpus

• A deep ALMA image of the Hubble Ultra Deep Field (2016, background): “…of known objects (e.g. Hodge et al. 2013; Karim et al. 2013; Ouchi et al. 2013; Bussmann et al. 2015; Capak et al. 2015; Maiolino et al. 2015; Simpson et al. 2015a, 2015b; Scoville et al. 2016), including gravitationally lensed sources (e.g. Weiss et al. 2013; Watson et al. 2015; Béthermin…”
• KILOPARSEC-SCALE DUST DISKS IN HIGH-REDSHIFT LUMINOUS SUBMILLIMETER GALAXIES (2016, methodology): “The Cycle 0 flux densities were taken from Hodge et al. (2013b) and have been corrected for the effect of flux boosting (e.g., Simpson et al. 2015a), which is a statistical enhancement, on average, of the measured fluxes for populations where fainter sources far outnumber the brighter ones.”
• GOODS-ALMA: 1.1 mm galaxy survey (2018, result): “16, we compare our results with previous studies (Lindner et al. 2011; Scott et al. 2012; Karim et al. 2013; Hatsukade et al. 2013; Simpson et al. 2015b; Oteo et al. 2016; Hatsukade et al. 2016; Aravena et al. 2016; Fujimoto et al. 2016; Umehata et al. 2017; Geach et al. 2017; Dunlop et al. 2017).”
• FORMING COMPACT MASSIVE GALAXIES (2015, methodology): “Finally, we note that we do not find a correlation between size and IR luminosity at fixed stellar mass, that is, an IR selection does not preferentially select compact galaxies but o - jects with a wide range of rest-frame optical sizes (see also Wiklind et al. 2014; Simpson et al. 2015).”
• An ALMA survey of the SCUBA-2 CLS UDS field: physical properties of 707 sub-millimetre galaxies (2019, methodology): “This connection has been strengthened by recent observations in the rest-frame far-infrared that suggest very compact extents of the star-forming regions (Toft et al. 2014; Ikarashi et al. 2015; Simpson et al. 2015a; Gullberg et al. 2019).”