J/MNRAS/469/2539 New classification of CALIFA galaxies (Kalinova+, 2017)
Towards a new classification of galaxies:
principal component analysis of CALIFA circular velocity curves.
Kalinova V., Colombo D., Rosolowsky E., Kannan R., Galbany L.,
Garcia-Benito R., Gonzalez Delgado R., Sanchez S.F., Ruiz-Lara T.,
Mendez-Abreu J., Catalan-Torrecilla C., Sanchez-Menguiano L.,
de Lorenzo-Caceres A., Costantin L., Florido E., Kodaira K., Marino R.A.,
Lasker R., Bland-Hawthorn J.
<Mon. Not. R. Astron. Soc., 469, 2539-2594 (2017)>
=2017MNRAS.469.2539K 2017MNRAS.469.2539K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Morphology
Keywords: methods: data analysis - methods: statistical - galaxies: evolution -
galaxies: kinematics and dynamics - galaxies: structure
Abstract:
We present a galaxy classification system for 238 (E1-Sdm) CALIFA
(Calar Alto Legacy Integral Field Area) galaxies based on the shapes
and amplitudes of their circular velocity curves (CVCs). We infer the
CVCs from the de-projected surface brightness of the galaxies, after
scaling by a constant mass-to-light ratio based on stellar dynamics -
solving axisymmetric Jeans equations via fitting the second velocity
moment Vrms=sqrt{V2+σ2} of the stellar kinematics. We
use principal component analysis (PCA) applied to the CVC shapes to
find characteristic features and use a k-means classifier to separate
circular curves into classes. This objective classification method
identifies four different classes, which we name slow-rising (SR),
flat (FL), round-peaked (RP) and sharp-peaked (SP) circular curves. SR
are typical for low-mass, late-type (Sb-Sdm), young, faint, metal-poor
and disc-dominated galaxies. SP are typical for high-mass, early-type
(E1-E7), old, bright, metal-rich and bulge-dominated galaxies. FL and
RP appear presented by galaxies with intermediate mass, age,
luminosity, metallicity, bulge-to-disc ratio and morphologies (E4-S0a,
Sa-Sbc). The discrepancy mass factor, fd=1-M*/Mdyn, have the
largest value for SR and SP classes (∼74 per cent and ∼71 per cent,
respectively) in contrast to the FL and RP classes (with ∼59 per cent
and ∼61 per cent, respectively). Circular curve classification
presents an alternative to typical morphological classification and
appears more tightly linked to galaxy evolution.
Description:
We select our galaxies from the sample of Falcon-Barroso et al. (2017,
Cat. J/A+A/597/A48), who provide reliable stellar kinematics of 300 galaxies
from the Calar Alto Legacy Integral Field Area (CALIFA) survey
(Sanchez et al., 2012A&A...538A...8S 2012A&A...538A...8S) observed until 2014 June.
The final sub-sample consists of 238 CALIFA targets with various masses and
morphologies from elliptical (E1) to late-type (Sdm) galaxies.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb.dat 88 238 Properties of the 238 (E1-Sdm) CALIFA galaxies
tablec1.dat 71 50 Main PC eigenvectors of the 238 CVCs
tabled.dat 73 238 The five main projections PCi of the 238 CVCs
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Byte-by-byte Description of file: tableb.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Galaxy Galaxy identifier
15- 17 A3 --- Type Hubble type based on by-eye morphological
classification from Walcher et al.
(2014, Cat. J/A+A/589/A1)
19- 21 I3 Mpc Dist Hubble flow (Galactocentric) distances (1)
23- 25 I3 deg PA Average photometric position angle (2)
27- 30 F4.2 --- eps Average photometric ellipticity (2)
32- 33 I2 deg Incl Inclination (3)
35- 36 I2 arcsec Re Effective (half-light) radius measured via
growth curve analysis (Walcher et al.,
2014, Cat. J/A+A/589/A1)
38- 39 I2 arcsec Rmax Radial extent of the stellar kinematic data
(Falcon-Barroso et al., 2017,
Cat. J/A+A/597/A48)
41- 43 F3.1 --- Rmax/Re Radial extent of the stellar kinematic data
in terms of effective radius
45- 48 I4 km/s Vsys Systemic velocity of the galaxies (4)
50- 55 F6.3 --- (M/L)dyn Median of the posterior distributions of the
dynamical mass-to-light ratios,
from JAM-MCMC model
57- 61 F5.3 --- E_(M/L)dyn Error on (M/L)dyn, upper value (5)
63- 67 F5.3 --- e_(M/L)dyn Error on (M/L)dyn, lower value (6)
69- 74 F6.3 --- betaz Median of the posterior distributions of the
azimuthal velocity anisotropies,
from JAM-MCMC model.
76- 80 F5.3 --- E_betaz Error on betaz, upper value (5)
82- 86 F5.3 --- e_betaz Error on betaz, lower value (6)
88 A1 --- CVC Circular velocity curve class (10)
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Note (1): from NED (using Hubble constant of H0=73km/s/Mpc), calculated from the
weighted mean radial velocities of the radio and optical redshifts, corrected
to the Galactic standard of rest (GSR) from the RC3 (Third Reference Catalogue
of Bright Galaxies, Cat. VII/155) as described in de Vaucouleurs et al.
(1991, section 3.10c, p. 54).
Note (2): from r-band SDSS (DR12) images with typical uncertainty of
5°-10° and 5 per cent, using findgalaxy python procedure of
Cappellari (2002MNRAS.333..400C 2002MNRAS.333..400C).
Note (3): from the axial ratio of the galaxies (q=1-epsilon, where epsilon is
the average ellipticity of the galaxy, determined from findgalaxy),
we calculated the inclination (i) assuming qo=0.2 for the intrinsic axial
ratio of the galaxies (Section 3.1).
Note (4): with a typical uncertainty of 5km/s, measured as the median value of
the velocity field (Section 2.2).
Note (5): 25th percentile of the data corresponding to the median absolute
deviation (Section 3.1).
Note (6): 75th percentile of the data corresponding to the median absolute
deviation (Section 3.1).
Note (10): Circular velocity curve class as follows:
0 = SR, slow-rising
1 = FL, flat
2 = RP, round-peaked
3 = SP, sharp-peaked
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Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 5 F5.3 --- R/Re Normalized PC radius
8- 17 F10.6 --- u1 PC eigenvector u1
20- 32 F13.9 --- u2 PC eigenvector u2
34- 45 F12.8 --- u3 PC eigenvector u3
48- 59 F12.9 --- u4 PC eigenvector u4
61- 71 F11.8 --- u5 PC eigenvector u5
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Byte-by-byte Description of file: tabled.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Galaxy Galaxy name
15- 25 F11.8 --- PC1 Main projections PC1
27- 37 F11.8 --- PC2 Main projections PC2
39- 49 F11.8 --- PC3 Main projections PC3
51- 61 F11.8 --- PC4 Main projections PC4
63- 73 F11.8 --- PC5 Main projections PC5
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 09-Apr-2020