J/MNRAS/439/1749 Barred S0 galaxies in the Coma cluster (Lansbury+, 2014)
Barred S0 galaxies in the Coma cluster.
Lansbury G.B., Lucey J.R., Smith R.J.
<Mon. Not. R. Astron. Soc., 439, 1749-1764 (2014)>
=2014MNRAS.439.1749L 2014MNRAS.439.1749L
ADC_Keywords: Galaxy catalogs ; Photometry, SDSS ; Morphology
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: kinematics and dynamics - galaxies: structure
Abstract:
This study uses r-band images from the Eighth Data Release of the
Sloan Digital Sky Survey (SDSS DR8) to study bars in lenticular (S0)
galaxies in one of the nearest rich cluster environments, the Coma
cluster. We develop techniques for bar detection and assess their
success when applied to SDSS image data. To detect and characterize
bars, we perform 2D bulge+disc+bar light decompositions of galaxy
images with galfit. Using a sample of artificial galaxy images, we
determine the faintest magnitude at which bars can be successfully
measured at the depth and resolution of SDSS. We perform detailed
decompositions of 83 S0 galaxies in Coma, 64 from a central sample,
and 19 from a cluster outskirt sample. For the central sample, the S0
bar fraction is 72+5-6%. This value is significantly higher than
that obtained using an ellipse-fitting method for bar detection,
48+6-6%. At a fixed luminosity, barred S0s are redder in g-r
colour than unbarred S0s by 0.02mag. The frequency and strength of
bars increase towards fainter luminosities. Neither central
metallicity nor stellar age distributions differ significantly between
barred and unbarred S0s. There is an increase in the bar fraction
towards the cluster core, but this is at a low significance level.
Bars have at most a weak correlation with cluster-centric radius.
Description:
The main 'central' sample of Coma cluster S0s was selected as
follows. The cluster centre was taken as the mid-point between
NGC 4874 and NGC 4889, (RA=194.9663°, DE=27.9681°). SDSS
galaxies within a 1.5° (2.5Mpc) radius from the centre were
selected.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 67 83 SDSS data and morphological classifications for the
83 lenticular (S0) galaxies in this investigation
tablea2.dat 83 83 *bulge+disc+bar decomposition parameters for the
83 S0s in this investigation
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Note on tablea2.dat: The parameters are for final accepted fitting stages only,
i.e. bulge+disc+bar for barred lenticulars (SB0) and bulge+disc for unbarred
lenticulars (S0).
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See also:
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- ID [1/83] Galaxy ID for this study (G1)
4- 22 I19 --- SDSS SDSS DR8 identification number (objID)
24- 29 F6.3 Mpc Rproj Projected cluster radius
31- 35 F5.3 [km/s] logsig Central velocity dispersion logσ
37- 42 F6.3 mag rmag SDSS r-band magnitude using the AB system
44- 48 F5.3 mag g-r g-r SDSS colour index
50- 52 A3 --- Type This paper Hubble type, "S0" or "SB0" (2)
54- 58 A5 --- Typ1 Dressler (1980ApJS...42..565D 1980ApJS...42..565D, Cat. VII/174)
Hubble type
60- 63 A4 --- Typ2 Michard & Andreon (2008A&A...490..923M 2008A&A...490..923M,
Cat. J/A+A/490/923) Hubble type
65 A1 --- ES [Y/N] Ellipse? strict detection (3)
67 A1 --- ER [Y/N] Ellipse? relaxed detection (4)
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Note (2): Hubble type as determined using the bar detection criteria in
Section 2.4.
Note (3): Yes/No to whether a bar was detected using the ellipse fitting of
galaxy isophotes, using strict detection criteria.
Note (4): Yes/No to whether a bar was detected using the ellipse fitting of
galaxy isophotes, using relaxed detection criteria.
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- ID [1/83] Galaxy ID for this study (G1)
4- 7 F4.2 % DRFF [0/5] Change in Residual Flux Fraction (RFF)
when a bar component is added to the model
(see Section 2.4)
9- 13 F5.2 % B/T [5/99] Bulge light fraction
15- 19 F5.2 % Bar/T [5/34]?=- Bar light fraction
21- 25 F5.2 kpc rB [0.1/31] Bulge effective radius
27- 31 F5.2 kpc rD [1/20] Disc effective radius
33- 36 F4.2 kpc rBar [0.6/4.4]?=- Bar effective radius
38- 42 F5.2 --- nB [0.4/18] Bulge Sersic index
44- 47 F4.2 --- nBar [0.2/0.9]? =- Bar Sersic index
49- 52 F4.2 --- (b/a)B [0/1] Bulge axial ratio
54- 57 F4.2 --- (b/a)D [0/1] Disc axial ratio
59- 62 F4.2 --- (b/a)Bar [0/1]?=- Bar axial ratio
64- 69 F6.2 deg PAB [-90/90] Bulge position angle
71- 76 F6.2 deg PAD [-90/90] Disc position angle
78- 83 F6.2 deg PABar [-90/90]?=- Bar position angle
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Global notes:
Note (G1): No. 1-64 are the central sample and
No. 65-83 are the outskirt sample.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 17-Dec-2014