J/ApJ/945/155 Color gradients & half-mass radii of 3D-HST gal. (Miller+, 2023)
Color gradients and half-mass radii of galaxies out to z=2 in the
CANDELS/3D-HST fields: further evidence for important differences in the
evolution of mass-weighted and light-weighted sizes.
Miller T.B., van Dokkum P., Mowla L.
<Astrophys. J., 945, 155 (2023)>
=2023ApJ...945..155M 2023ApJ...945..155M
ADC_Keywords: Galaxies, photometry; Redshifts; Galaxies, radius; Colors;
Optical
Keywords: Galaxy structure ; Galaxy radii ; High-redshift galaxies
Abstract:
Recent studies have indicated that the ratio between half-mass and
half-light radii, rmass/rlight, varies significantly as a function
of stellar mass and redshift, complicating the interpretation of the
ubiquitous rlight-M* relation. To investigate, in this study we
construct the light and color profiles of ∼3000 galaxies at 1<z<2 with
logM*/M☉>10.25 using imcascade, a Bayesian implementation of
the Multi-Gaussian Expansion (MGE) technique. imcascade flexibly
represents galaxy profiles using a series of Gaussians, free of any a
priori parameterization. We find that both star-forming and quiescent
galaxies have, on average, negative color gradients. For star-forming
galaxies, we find steeper gradients that evolve with redshift and
correlate with dust content. Using the color gradients as a proxy for
gradients in the M/L ratio, we measure half-mass radii for our sample
of galaxies. There is significant scatter in individual rmass/rlight
ratios, which is correlated with variation in the color gradients. We
find that the median rmass/rlight ratio evolves from 0.75 at z=2 to
0.5 at z=1, consistent with previous results. We characterize the
rmass-M* relation, and we find that it has a shallower slope and
shows less redshift evolution than the rlight-M* relation. This
applies both to star-forming and quiescent galaxies. We discuss some
of the implications of using rmass instead of rlight, including an
investigation of the size-inclination bias and a comparison to
numerical simulations.
Description:
We derive the galaxy sample for this study from the 3D-HST catalog
(Brammer+ 2012ApJS..200...13B 2012ApJS..200...13B; Skelton+ 2014, J/ApJS/214/24). This
catalog uses FAST to derive stellar masses and EAZY to derive
rest-frame colors (Brammer+ 2008ApJ...686.1503B 2008ApJ...686.1503B and
Kriek+ 2018ascl.soft03008K). We select all galaxies in the catalog
with 1<z<2, S/NF125W>25 and S/NF160W>25, which is equivalent to
mF160W<23.
This sample contains a total of 3481 galaxies. As a supplement, we use
the size catalog from van der Wel+ (2012, J/ApJS/203/24), who measured
structural parameters of the galaxies using Sersic models.
In this study, we utilize HST data from the five fields (UDS, AEGIS,
COSMOS, GOODSS, and GOODSN) studied in the CANDELS survey. We use the
mosaics produced by the 3D-HST survey (Skelton+ 2014). We utilize the
F160W and the PSF-matched F125W mosaic. See Section 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 101 3527 Measurements of half-light radii, half-mass radii
and color gradients using imcascade
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJS/203/24 : Structural param. of galaxies in CANDELS (van der Wel+, 2012)
J/ApJ/777/18 : Stellar mass functions of galaxies to z=4 (Muzzin+, 2013)
J/ApJ/762/77 : PM2GC mass-limited sample surface phot. (Poggianti+, 2013)
J/ApJ/763/73 : Surface density profiles of GOODS-South gal. (Szomoru+, 2013)
J/ApJ/793/101 : CANDELS z∼2 galaxy properties (Trump+, 2014)
J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)
J/ApJS/225/27 : 3D-HST Survey: grism spectra master catalog (Momcheva+, 2016)
J/ApJ/835/153 : Galaxy env. in the 3D-HST fields (z=0.5-3) (Fossati+, 2017)
J/ApJ/854/29 : High-EW [OIII] & Hα emitters from 3D-HST (Maseda+, 2018)
J/ApJ/877/103 : Half-mass radii for ∼7000 gal. at 1.0≤z≤2.5 (Suess+, 2019)
J/ApJ/905/170 : Mass-based structural param. for 3D-HST gal. (Mosleh+, 2020)
J/ApJ/901/74 : ALMA obs. of UDS and GOODS-S massive galaxies (Tadaki+, 2020)
J/MNRAS/493/87 : 1005 galaxies with z<0.09 sample (Trujillo+, 2020)
J/ApJ/937/L33 : JWST morphological param. at 4.4um & 1.5um (Suess+, 2022)
http://archive.stsci.edu/prepds/3d-hst/ : 3D-HST on MAST
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Field Field ("AEGIS"; "COSMOS"; "GOODS-N";
"GOODS-S" or "UDS")
9- 13 I5 --- ID [2/50460] 3D-HST Field id (1)
15- 25 F11.7 deg RAdeg [34.2/215.4] Right Ascension (J2000) (1)
27- 38 F12.8 deg DEdeg [-28/62.4] Declination (J2000) (1)
40- 46 F7.5 --- z [1/2] Redshift (1)
48- 52 F5.2 [Msun] logMs [10.26/13.74] log, stellar mass (2)
54- 58 A5 --- Quenched Is quenched? True or False (3)
60- 66 F7.3 kpc rlight [0.3/118] Half-light radius (4)
68- 73 F6.3 kpc e_rlight [0/36] Uncertainty in (4)
75- 81 F7.3 kpc rmass [-0.83/165] Half-mass radius (4)
83- 88 F6.3 kpc e_rmass [0/55.1] Uncertainty in (4)
90- 95 F6.3 --- g(g-r) [-2.5/2.5]? Color gradient, d(g-r)/dlogr (5)
97-101 F5.3 --- e_g(g-r) [0/1.3]? Uncertainty in g(g-r) (5)
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Note (1): Taken from 3D-HST catalog, Skelton+ (2014, J/ApJS/214/24 ;
<[SWM2014] {Field} NNNNN> in Simbad)
Note (2): Taken from 3D-HST catalog, calculated using FAST,
Skelton+ (2014, J/ApJS/214/24)
Note (3): According to rest-frame UVJ colors following
Muzzin+ 2013, J/ApJ/777/18
Note (4): Median value from posterior. The uncertainty is half of the
16th-84th percentile range.
Note (5): The color gradient is measured between 0.5 and 2 rlight,
see Sec. 3 for more details.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Feb-2025