J/MNRAS/458/963 CANDELS galaxy structure classification (Peth+, 2016)
Beyond spheroids and discs: classifications of CANDELS galaxy structure at
1.4 < z < 2 via principal component analysis.
Peth M.A., Lotz J.M., Freeman P.E., McPartland C., Mortazavi S.A.,
Snyder G.F., Barro G., Grogin N.A., Guo Y., Hemmati S., Kartaltepe J.S.,
Kocevski D.D., Koekemoer A.M., McIntosh D.H., Nayyeri H., Papovich C.,
Primack J.R., Simons R.C.
<Mon. Not. R. Astron. Soc., 458, 963-987 (2016)>
=2016MNRAS.458..963P 2016MNRAS.458..963P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Redshifts ; Morphology
Keywords: methods: statistical - catalogues - galaxies: evolution -
galaxies: structure
Abstract:
Important but rare and subtle processes driving galaxy morphology and
star formation may be missed by traditional spiral, elliptical,
irregular or Sersic bulge/disc classifications. To overcome this
limitation, we use a principal component analysis (PCA) of
non-parametric morphological indicators (concentration, asymmetry,
Gini coefficient, M20, multimode, intensity and deviation) measured
at rest-frame B band (corresponding to HST/WFC3 F125W at 1.4<z<2) to
trace the natural distribution of massive (>1010M☉) galaxy
morphologies. PCA quantifies the correlations between these
morphological indicators and determines the relative importance of
each. The first three principal components (PCs) capture ∼75 per cent
of the variance inherent to our sample. We interpret the first PC as
bulge strength, the second PC as dominated by concentration and the
third PC as dominated by asymmetry. Both PC1 and PC2 correlate with
the visual appearance of a central bulge and predict galaxy
quiescence. PC1 is a better predictor of quenching than stellar mass,
as good as other structural indicators (Sersic-n or compactness). We
divide the PCA results into groups using an agglomerative hierarchical
clustering method. Unlike Sersic, this classification scheme separates
compact galaxies from larger, smooth protoelliptical systems, and
star-forming disc-dominated clumpy galaxies from star-forming
bulge-dominated asymmetric galaxies. Distinguishing between these
galaxy structural types in a quantitative manner is an important step
towards understanding the connections between morphology, galaxy
assembly and star formation.
Description:
We use the CANDELS H-band (F160W) selected multiwavelength catalogues
(UDS, Galametz et al. 2013, Cat. J/ApJS/206/10; GOODS-S, Guo et al.
2013, Cat. J/ApJS/207/24; COSMOS, Nayyeri et al. in preparation),
photometric redshifts (Dahlen et al., 2013ApJ...775...93D 2013ApJ...775...93D),
non-parametric morphologies (this work), Sersic parameters (van der
Wel et al., 2012, Cat. J/ApJS/203/24), visual classifications
(Kartaltepe et al., 2015, Cat. J/ApJS/221/11), rest-frame photometry,
and stellar masses (this work). The limiting magnitude for HST/WFC3
F125W and F160W are 27.35 and 27.45, respectively, with full width
half-maximum (FWHM) of ∼0.135arcsec and ∼0.15arcsec, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 232 1244 Non-parametric morphology statistics and PC
values for CANDELS (UDS/GOODS-S/COSMOS) galaxies
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See also:
J/ApJS/207/24 : GOODS-S CANDELS multiwavelength catalog (Guo+, 2013)
J/ApJS/206/10 : CANDELS multiwavelength catalog (Galametz+, 2013)
J/ApJS/203/24 : CANDELS galaxies structural parameters (van der Wel+, 2012)
J/ApJS/221/11 : CANDELS visual classifications for GOODS-S (Kartaltepe+, 2015)
J/ApJ/801/97 : GOODS-S+UDS stellar mass catalogs from CANDELS (Santini+, 2015)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID Galaxy identification number,
from Galametz et al., Cat. J/ApJS/206/10
7- 16 F10.6 deg RAdeg ?=-99 Rigth ascension (J2000)
18- 27 F10.6 deg DEdeg ?=-99 Declination (J2000)
29- 36 F8.6 --- CJ Concentration index (1)
38- 46 F9.6 --- AsymJ Asymmetry (1)
48- 56 F9.6 --- M20J M2, second order moment of the brightest
regions of a galaxy (1)
58- 65 F8.6 --- GINIJ Gini coefficient (1)
67- 76 F10.6 --- MJ ?=-99 Multimode statistic (ratio, in pixels,
of the two brightest regions of a galaxy) (1)
78- 85 F8.6 --- IJ Intensity (ratio, in flux, of the two
brightest regions) (1)
87- 94 F8.6 --- DJ Deviation (distance between the intensity
centroid of a galaxy and the center of the
brightest region) (1)
96-104 F9.6 [Msun] logMass Mass
106-113 F8.6 --- zphot Photometric redshift
115-116 I2 --- Group Group number
118-126 F9.6 --- PC1 Principal component 1
(bulge strength indicator)
128-136 F9.6 --- PC2 Principal component 2
(dominated by concentration)
138-147 F10.6 --- PC3 Principal component 3 (dominated by asymmetry)
149-157 F9.6 --- PC4 Principal component 4
159-167 F9.6 --- PC5 Principal component 5
169-177 F9.6 --- PC6 Principal component 6
179-187 F9.6 --- PC7 Principal component 7
189-192 F4.2 --- pGoutlier Probability of a galaxy being outlier
194-197 F4.2 --- pG0 Probability of a galaxy being in group 0
199-202 F4.2 --- pG1 Probability of a galaxy being in group 1
204-207 F4.2 --- pG2 Probability of a galaxy being in group 2
209-212 F4.2 --- pG4 Probability of a galaxy being in group 4
214-217 F4.2 --- pG5 Probability of a galaxy being in group 5
219-222 F4.2 --- pG6 Probability of a galaxy being in group 6
224-227 F4.2 --- pG8 Probability of a galaxy being in group 8
229-232 F4.2 --- pG9 Probability of a galaxy being in group 9
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Note (1): measured at rest-frame J-band.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-May-2017