J/ApJ/836/115 Double-component model fitting of elliptical gal. (Oh+, 2017)
Testing the presence of multiple photometric components in nearby early-type
galaxies using SDSS.
Oh S., Greene J.E., Lackner C.N.
<Astrophys. J., 836, 115-115 (2017)>
=2017ApJ...836..115O 2017ApJ...836..115O (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical ; Photometry, SDSS ; Redshifts ; Morphology ;
Models
Keywords: galaxies: elliptical and lenticular, cD; galaxies: evolution
Abstract:
We investigate two-dimensional image decomposition of nearby,
morphologically selected early-type galaxies (ETGs). We are motivated
by recent observational evidence of significant size growth of
quiescent galaxies and theoretical development advocating a two-phase
formation scenario for ETGs. We find that a significant fraction of
nearby ETGs show changes in isophotal shape that require
multi-component models. The characteristic sizes of the inner and
outer component are ∼3 and ∼15kpc. The inner component lies on the
mass-size relation of ETGs at z∼0.25-0.75, while the outer component
tends to be more elliptical and hints at a stochastic buildup process.
We find real physical differences between single- and double-component
ETGs, with double-component galaxies being younger and more
metal-rich. The fraction of double-component ETGs increases with
increasing σ and decreases in denser environments. We
hypothesize that double-component systems were able to accrete gas and
small galaxies until later times, boosting their central densities,
building up their outer parts, and lowering their typical central
ages. In contrast, the oldest galaxies, perhaps due to residing in
richer environments, have no remaining hints of their last accretion
episode.
Description:
We use the detailed visual morphology classification catalog of Nair &
Abraham (2010, J/ApJS/186/427) to construct a sample of nearby
elliptical galaxies in a range of mass and environment. The catalog is
based on the SDSS DR4 main spectroscopic sample, and extends to z=0.1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 138 838 Structural parameters of bestfit models
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See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/AJ/101/1561 : Isophotometry of ellipticals in Abell clusters (Porter+ 1991)
J/ApJS/142/1 : DEEP Groth Strip Survey. II. (Simard+, 2002)
J/MNRAS/330/547 : Local galaxy ages and metallicities (Terlevich+, 2002)
J/ApJS/182/216 : Surface photometry of Virgo ellipticals (Kormendy+, 2009)
J/ApJS/186/427 : Detailed morphology of SDSS galaxies (Nair+, 2010)
J/ApJ/720/723 : Compact galaxies in the local universe (Taylor+, 2010)
J/ApJ/739/L44 : Structural data for gal. between 0.2<z<2.7 (Damjanov+, 2011)
J/MNRAS/414/888 : ATLAS3D project. III. (Emsellem+, 2011)
J/ApJS/203/24 : Structural parameters of gal. in CANDELS (van der Wel+, 2012)
J/ApJ/775/106 : CANDELS passive and massive early-type gal. (Cassata+, 2013)
J/ApJ/793/39 : Spectrosc. properties of BOSS compact gal. (Damjanov+, 2014)
J/MNRAS/446/3943 : galaxies 2D phot. decompositions in SDSS-DR7 (Meert+, 2015)
J/A+A/578/A134 : Compact early-type galaxies in SDSS (Saulder+, 2015)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID [0/1132] Unique sample ID
6- 25 A20 --- Name SDSS name (JHHMMSS.ss+DDMMSS.ss)
27- 33 F7.3 deg RAdeg ? Right Ascension in decimal degrees (J2000)
35- 41 F7.3 deg DEdeg ? Declination in decimal degrees (J2000)
43- 47 F5.3 --- z [0.01/0.09] Spectroscopic redshift
49- 51 I3 km/s sigma [72/354] Velocity dispersion
53- 58 F6.2 mag rMag [-22.9/-18.4]? Absolute r magnitude
60- 63 F4.2 mag g-r [0.5/0.9]? Rest frame g-r color index
65- 68 F4.2 arcsec FWHM [0.7/2.1] FWHM of the PSF
70- 72 F3.1 --- nSer [1.4/9] Sersic index for Sersic model
74- 77 F4.2 --- eSer [0/0.6] Ellipticity for Sersic model
79- 83 F5.2 mag fSer [12/15.7] Flux for Sersic model
85- 89 F5.2 arcsec ReSer [1.6/94] Effective radius for Sersic model
91 I1 --- flag [0/2]? Flag on double component early-type
galaxies (ETGs) (1)
93- 96 F4.2 --- edeV [0.01/0.6]? Ellipticity for deV component
of deVExp model (2)
98-102 F5.1 deg padeV ? Position angle for deV component
of deVExp model (2)
104-108 F5.2 arcsec RedeV [0.5/17.1]? Effective radius for deV component
of deVExp model (2)
110-114 F5.2 mag fdeV [12.7/17]? Flux for deV component of
deVExp model (2)
116-119 F4.2 --- eExp [0.01/0.8]? Ellipticity for Exp component
of deVExp model (2)
121-125 F5.1 deg paExp ? Position angle for Exp component
of deVExp model (2)
127-132 F6.2 arcsec ReExp [4/116]? Effective radius for Exp component
of deVExp model (2)
134-138 F5.2 mag fExp [13.3/17]? Flux for Exp component of
deVExp model (2)
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Note (1): Flag as follows:
0 = single component;
1 = double component;
2 = double component with high confidence.
See section 3.2 of the paper.
Note (2): The two-component model (devExp) is a sum of a de Vaucouleurs and
an exponential with Sersic indices of n=4 and n=1, respectively.
The two components share a common center, but are allowed to have
different PA and ellipticity.
See section 3.1 for the fitting procedure.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Sep-2017