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Testing the Recovery of Intrinsic Galaxy Sizes and Masses of z ∼ 2 Massive Galaxies Using Cosmological Simulations

Price, Sedona H. and Kriek, Mariska and Feldmann, Robert and Quataert, Eliot and Hopkins, Philip F. and Faucher-Giguère, Claude-André and Kereš, Dušan and Barro, Guillermo (2017) Testing the Recovery of Intrinsic Galaxy Sizes and Masses of z ∼ 2 Massive Galaxies Using Cosmological Simulations. Astrophysical Journal Letters, 844 (1). Art. No. L6. ISSN 2041-8205.

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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_☉_.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Price, Sedona H.0000-0002-0108-4176
Kriek, Mariska0000-0002-7613-9872
Feldmann, Robert0000-0002-1109-1919
Quataert, Eliot0000-0001-9185-5044
Hopkins, Philip F.0000-0003-3729-1684
Faucher-Giguère, Claude-André0000-0002-4900-6628
Kereš, Dušan0000-0002-1666-7067
Barro, Guillermo0000-0001-6813-875X
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.
Group:TAPIR, Astronomy Department
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE 1106400
NASA Hubble FellowshipHF2-51304.001-A
NASANAS 5-26555
UC Berkeley Theoretical Astrophysics CenterUNSPECIFIED
Swiss National Science Foundation (SNSF)157591
Alfred P. Sloan FoundationUNSPECIFIED
Cottrell Scholar of Research CorporationUNSPECIFIED
Subject Keywords:galaxies: evolution; galaxies: high-redshift; galaxies: structure
Issue or Number:1
Record Number:CaltechAUTHORS:20170803-083236533
Persistent URL:
Official Citation:Sedona H. Price et al 2017 ApJL 844 L6
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:79814
Deposited By: Ruth Sustaita
Deposited On:04 Aug 2017 23:45
Last Modified:09 Sep 2020 15:52

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