Testing the Recovery of Intrinsic Galaxy Sizes and Masses of z ∼ 2 Massive Galaxies Using Cosmological Simulations
Abstract
Accurate measurements of galaxy masses and sizes are key to tracing galaxy evolution over time. Cosmological zoom-in simulations provide an ideal test bed for assessing the recovery of galaxy properties from observations. Here, we utilize galaxies with M_* ~ 10^10 - 10^(11.5) M_☉ at z ~ 1.7–2 from the MassiveFIRE cosmological simulation suite, part of the Feedback in Realistic Environments (FIRE) project. Using mock multi-band images, we compare intrinsic galaxy masses and sizes to observational estimates. We find that observations accurately recover stellar masses, with a slight average underestimate of ~ 0.06 dex and a ~ 0.15 dex scatter. Recovered half-light radii agree well with intrinsic half-mass radii when averaged over all viewing angles, with a systematic offset of ~ 0.1 dex (with the half-light radii being larger) and a scatter of ~ 0.2 dex. When using color gradients to account for mass-to-light variations, recovered half-mass radii also exceed the intrinsic half-mass radii by ~ 1 dex. However, if not properly accounted for, aperture effects can bias size estimates by ~ 0.1 dex. No differences are found between the mass and size offsets for star-forming and quiescent galaxies. Variations in viewing angle are responsible for ~25% of the scatter in the recovered masses and sizes. Our results thus suggest that the intrinsic scatter in the mass–size relation may have previously been overestimated by ~25%. Moreover, orientation-driven scatter causes the number density of very massive galaxies to be overestimated by ~ 0.5 dex at M_* ~ 10^(11.5) M_☉_.
Additional Information
© 2017 American Astronomical Society. Received 2017 May 9. Accepted 2017 July 3. Published 2017 July 18. We acknowledge valuable discussions with M. Franx, D. Szomoru, K. Whitaker, C. Hayward, C.-P. Ma, and K. Suess. This work made use of astropy (Robitaille et al. 2013) and pysynphot (Lim et al. 2015). S.P. was supported by a National Science Foundation Graduate Research Fellowship under grant DGE 1106400. M.K. acknowledges support from NSF AAG grant 1313171 and STScI grants AR-13907 and AR-12847, provided by NASA through a grant from the Space Telescope Science Institute. R.F. was supported in part by NASA through Hubble Fellowship grant HF2-51304.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555, by the Theoretical Astrophysics Center at UC Berkeley, and by the Swiss National Science Foundation (grant No. 157591). R.F. and E.Q. acknowledge support from NASA ATP grant 12-ATP-120183. P.H. was supported by an Alfred P. Sloan Research Fellowship, NASA ATP grant NNX14AH35G, and NSF Collaborative Research grant 1411920 and CAREER grant 1455342. C.A.F.G. was supported by NSF grants AST-1412836 and AST-1517491, NASA grant NNX15AB22G, and STScI grant HST-AR-14562.001. D.K. acknowledges support from NSF grant AST-1412153 and a Cottrell Scholar Award from the RCSA.Attached Files
Published - Price_2017_ApJL_844_L6.pdf
Submitted - 1707.01094.pdf
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Additional details
- Eprint ID
- 79814
- Resolver ID
- CaltechAUTHORS:20170803-083236533
- NSF Graduate Research Fellowship
- DGE 1106400
- NSF
- AST-1313171
- NASA
- AR-13907
- NASA
- AR-12847
- NASA Hubble Fellowship
- HF2-51304.001-A
- NASA
- NAS 5-26555
- UC Berkeley Theoretical Astrophysics Center
- Swiss National Science Foundation (SNSF)
- 157591
- NASA
- 12-ATP-120183
- Alfred P. Sloan Foundation
- NASA
- NNX14AH35G
- NSF
- AST-1411920
- NSF
- AST-1455342
- NSF
- AST-1412836
- NSF
- AST-1517491
- NASA
- NNX15AB22G
- NASA
- HST-AR-14562.001
- NSF
- AST-1412153
- Cottrell Scholar of Research Corporation
- Created
-
2017-08-04Created from EPrint's datestamp field
- Updated
-
2021-11-15Created from EPrint's last_modified field
- Caltech groups
- TAPIR, Astronomy Department