J/ApJ/877/103 Half-mass radii for ∼7000 galaxies at 1.0≤z≤2.5 (Suess+, 2019)
Half-mass radii for ∼7000 galaxies at 1.0≤z≤2.5: most of the evolution in the
mass-size relation is due to color gradients.
Suess K.A., Kriek M., Price S.H., Barro G.
<Astrophys. J., 877, 103 (2019)>
=2019ApJ...877..103S 2019ApJ...877..103S
ADC_Keywords: Galaxies, photometry; Morphology; Redshifts
Keywords: galaxies: evolution ; galaxies: formation ; galaxies: structure
Abstract:
Radial mass-to-light ratio gradients cause the half-mass and
half-light radii of galaxies to differ, potentially biasing studies
that use half-light radii. Here we present the largest catalog to date
of galaxy half-mass radii at z>1: 7006 galaxies in the CANDELS fields
at 1.0≤z≤2.5. The sample includes both star-forming and quiescent
galaxies with stellar masses 9.0≤log(M*/M☉)≤11.5. We test
three methods for calculating half-mass radii from multiband
PSF-matched Hubble Space Telescope (HST) imaging: two based on
spatially resolved spectral energy distribution modeling, and one that
uses a rest-frame color profile. All three methods agree, with scatter
≲0.3dex. In agreement with previous studies, most galaxies in our
sample have negative color gradients (the centers are redder than the
outskirts, and re,mass<re,light). We find that color gradient
strength has significant trends with increasing stellar mass,
half-light radius, U-V color, and stellar mass surface density. These
trends have not been seen before at z>1. Furthermore, color gradients
of star-forming and quiescent galaxies show a similar redshift
evolution: they are flat at z≳2, then steeply decrease as redshift
decreases. This affects the galaxy mass-size relation. The
normalizations of the star-forming and quiescent rmass-M*
relations are 10%-40% smaller than the corresponding rlight-M*
relations; the slopes are ∼0.1-0.3dex shallower. Finally, the
half-mass radii of star-forming and quiescent galaxies at
M*=1010.5M☉ only grow by ∼1% and ∼8% between z∼2.25 and
z∼1.25. This is significantly less than the ∼37% and ∼47% size
increases found when using the half-light radius.
Description:
For our sample selection, we use the multiwavelength photometric
catalogs from ZFOURGE (Straatman+ 2016, J/ApJ/830/51), which overlap
with the CANDELS survey in the COSMOS, GOODS-S, and UDS fields. These
catalogs contain medium- and broad-band photometry spanning from the
optical to IRAC, for a total of 26-40 photometric bands.
We also make extensive use of the high-resolution multiband imaging
and integrated photometry in the COSMOS, UDS, and GOODS-S fields
obtained by the CANDELS program (Grogin+ 2011ApJS..197...35G 2011ApJS..197...35G &
Koekemoer+ 2011ApJS..197...36K 2011ApJS..197...36K). For this analysis, we use the
PSF-matched images created by the 3D-HST team
(Skelton+ 2014, J/ApJS/214/24 and Momcheva+ 2016, J/ApJS/225/27).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 146 7006 Half-mass radii for 7006 galaxies
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See also:
J/ApJ/655/51 : HDFS IRAC observations of 2<z<3.5 galaxies (Wuyts+, 2007)
J/ApJ/739/L44 : Structural data for gal. between 0.2<z<2.7 (Damjanov+, 2011)
J/ApJ/749/121 : Surface brightness profiles if z=2 galaxies (Szomoru+, 2012)
J/ApJS/203/24 : Structural parameters of gal. in CANDELS (van der Wel+, 2012)
J/ApJS/206/10 : CANDELS multiwavelength catalog (Galametz+, 2013)
J/ApJ/763/73 : Surface density profiles of GOODS-South gal. (Szomoru+, 2013)
J/ApJ/771/85 : Dynamical masses of z∼2 quiescent gal. (van de Sande+, 2013)
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/830/51 : FourStar galaxy evolution survey (ZFOURGE) (Straatman+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID [161/50461] 3D-HST catalog (v4.0) identifier
(<[SWM2014] {Field} NNNNN> in Simbad)
7- 13 A7 --- Field Field identifier (COSMOS, GOODS-S or UDS)
15- 24 F10.6 deg RAdeg [34.22/150.21] Right Ascension (J2000) (1)
26- 35 F10.6 deg DEdeg [-27.9/2.4] Declination (J2000) (1)
37- 40 F4.2 --- z [1/2.5] Photometric redshift (2)
42- 46 F5.2 [Msun] logM* [9/11.8] log stellar mass (3)
48- 54 F7.3 kpc re [0.14/208.4]? Effective half light radius (4)
56- 61 F6.3 kpc e_re [0/71.2]? Uncertainty in re
63- 67 F5.3 --- n [0.2/8] Sersic index (5)
69- 73 F5.3 --- e_n [0/4.7] Uncertainty in n (5)
75- 80 F6.3 kpc rem1 [0.15/79.3]? Method 1 effective half mass
radius (6)
82- 87 F6.3 kpc e_rem1 [0.14/66.4]? Lower 16% percentile
uncertainty in rem1
89- 94 F6.3 kpc E_rem1 [0.18/99.5]? Upper 84% percentile
uncertainty in rem1
96-102 F7.3 kpc rem2 [0.25/203.2]? Method 2 effective half mass
radius (6)
104-110 F7.3 kpc e_rem2 [0.25/203]? Lower 16% percentile
uncertainty in rem2
112-118 F7.3 kpc E_rem2 [0.28/203.4]? Upper 84% percentile
uncertainty in rem2
120-125 F6.3 kpc rem3 [0.14/58.3]? Method 3 effective half mass
radius (6)
127-132 F6.3 kpc e_rem3 [0.14/50.9]? Lower 16% percentile
uncertainty in rem3
134-140 F7.3 kpc E_rem3 [0.15/100]? Upper 84% percentile
uncertainty in rem3
142-146 A5 --- isQui Galaxy classified as quiescent (7)
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Note (1): Taken from van der Wel+ (2012, J/ApJS/203/24) catalog
to match the morphological measurements.
Note (2): Taken from the ZFOURGE catalog (Straatman+ 2016, J/ApJ/830/51).
By comparing photometric and spectroscopic redshifts, Straatman+
(2016) estimate photometric redshift errors of Δz/(1+z)∼0.01.
Note (3): Taken from the ZFOURGE catalog (Straatman+ 2016, J/ApJ/830/51).
Corrected to be consistent with morphological measurements by
multiplying the catalog mass by the ratio of the total F160W flux
measured by GALFIT to the total F160W flux measured in the
Straatman+ (2016) catalog. Uncertainties on stellar masses are
dominated by systematics, and are estimated to be ∼0.2-0.3dex.
Note (4): From the van der Wel+ (2012, J/ApJS/203/24) catalogs.
Corrected to rest-frame 5000Å using the procedure in
van der Wel+ (2014ApJ...788...28V 2014ApJ...788...28V).
Note (5): From the van der Wel+ (2012, J/ApJS/203/24) catalogs.
Note (6): In this paper, we explore three different methods to calculate
half-mass radii.
We introduce a new technique that builds on the methods used by
Wuyts+ (2012ApJ...753..114W 2012ApJ...753..114W): we divide the galaxy into annuli,
measure multiband aperture photometry in each annulus, then use
stellar population synthesis (SPS) modeling to fit the resulting SEDs
and obtain a mass map of the galaxy. We then use two separate
techniques to account for the HST PSF and derive the intrinsic mass
profiles.
The first approach uses a forward-modeling technique that assumes the
mass-to-light ratio gradient is a power-law function of radius;
the second approach uses GALFIT (Peng+ 2002AJ....124..266P 2002AJ....124..266P) to fit the
mass map of the galaxy.
Our third and final method replicates the analysis of Szomoru+
(2010ApJ...714L.244S 2010ApJ...714L.244S & 2012, J/ApJ/749/121 and 2013, J/ApJ/763/73) and
uses the rest-frame intrinsic u-g color profile to create a mass
profile and measure a half-mass radius.
See Section 3 for further details.
Note (7): Using a UVJ color selection ("True" indicates that the galaxy is
quiescent, and "False" indicates that it is star-forming). The
selection is described in the text.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Nov-2020