Star Formation at at z = 2.481 in the Lensed Galaxy SDSS J1110+6459. II. What is Missed at the Normal Resolution of the Hubble Space Telescope?
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Author(s)
Rigby, J. R.
Johnson, T. L.
Sharon, K.
Whitaker, K.
Gladders, M. D.
Florian, M.
Lotz, J.
Wuyts, E.
Bayliss, Matthew B
Date Issued
July 2017
Journal
The Astrophysical Journal
Publisher
The American Astronomical Society
Citation
Rigby, J. R., et al. “Star Formation at Z = 2.481 in the Lensed Galaxy SDSS J1110+6459. II. What Is Missed at the Normal Resolution of the Hubble Space Telescope ?” The Astrophysical Journal, vol. 843, no. 2, July 2017, p. 79. © 2017 The American Astronomical Society
Version
Final published version
Abstract
For lensed galaxy SGAS J111020.0+645950.8 at redshift z = 2.481, which is magnified by a factor of 28 ± 8, we analyze the morphology of star formation, as traced by rest-frame ultraviolet emission, in both the highly magnified source plane and simulations of how this galaxy would appear without lensing magnification. Were this galaxy not lensed, but rather drawn from a Hubble Space Telescope deep field, we would conclude that almost all its star formation arises from an exponential disk (Sérsic index of 1.0 ± 0.4) with an effective radius of r[subscript e]=2.7 ± 0.3 measured from two-dimensional fitting to F606W using Galfit, and r[subscript e]=1.9 ± 0.1 kpc measured by fitting a radial profile to F606W elliptical isophotes. At the normal spatial resolution of the deep fields, there is no sign of clumpy star formation within SGAS J111020.0+645950.8. However, the enhanced spatial resolution enabled by gravitational lensing tells a very different story; much of the star formation arises in two dozen clumps with sizes of r = 30–50 pc spread across the 7 kpc length of the galaxy. The color and spatial distribution of the diffuse component suggests that still-smaller clumps are unresolved. Despite this clumpy, messy morphology, the radial profile is still well-characterized by an exponential profile. In this lensed galaxy, stars are forming in complexes with sizes well below 100 pc; such sizes are wholly unexplored by surveys of galaxy evolution at 1 < z < 3.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.3847/1538-4357/aa775e
