J/ApJ/588/218 i*g* photometry of SDSS EDR galaxies (Abraham+, 2003)
A new approach to galaxy morphology.
I. Analysis of the Sloan Digital Sky Survey Early Data Release.
Abraham R.G., van den Bergh S., Nair P.
<Astrophys. J. 588, 218 (2003)>
=2003ApJ...588..218A 2003ApJ...588..218A
ADC_Keywords: Galaxies, photometry ; Photometry, SDSS ; Redshifts
Keywords: galaxies: evolution - galaxies: fundamental parameters
Abstract:
In this paper we present a new statistic for quantifying galaxy
morphology based on measurements of the Gini coefficient of galaxy
light distributions. This statistic is easy to measure and is commonly
used in econometrics to measure how wealth is distributed in human
populations. When applied to galaxy images, the Gini coefficient
provides a quantitative measure of the inequality with which a
galaxy's light is distributed among its constituent pixels. We measure
the Gini coefficient of local galaxies in the Early Data Release of
the Sloan Digital Sky Survey and demonstrate that this quantity is
closely correlated with measurements of central concentration, but
with significant scatter.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 124 930 SDSS Early Data Release g*<16mag Sample
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See also:
http://www.sdss.org : SDSS Home Page
J/AJ/125/1817 : SDSS Early-Type Galaxies Catalog (Bernardi+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [00]
3- 21 A19 --- [AVN2003] Identification number (1)
23- 29 F7.5 --- z Redshift
31- 35 F5.2 --- MOD Distance Modulus (2)
37- 41 F5.2 mag i*mag Isophotal i* band magnitude (3)
43- 47 F5.3 --- i*Con Central i* band concentration
49- 53 F5.3 --- i*Gini The i* band Gini coefficient
55- 59 F5.3 --- e_i*Gini The 1σ error in iGini
61- 65 F5.2 mag/arcsec2 i*SB Mean i* band surface brightness
67- 71 F5.3 --- i*Rat The i* band axial ratio (b/a)
73- 78 F6.3 mag i*zp The i* band zero point
80- 85 F6.3 mag g*mag Isophotal g* band magnitude (4)
87- 91 F5.3 --- g*Con Central g* band concentration
93- 97 F5.3 --- g*Gini The g* band Gini coefficient
99-103 F5.3 --- e_g*Gini The 1σ error in gGini
105-109 F5.2 mag/arcsec2 g*SB Mean g* band surface brightness
111-115 F5.3 --- g*Rat The g* band axial ratio (b/a)
117-122 F6.3 mag g*zp The g* band zero point
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Note (1): Designation from SDSS EDR Database.
[AVN2003] NNNNNN-NN-N-NNNN-NNNN in Simbad
Note (2): Assuming H0=70km/s/Mpc, ΩM=0.3, ΩΛ=0.7
Note (3): Above i*=24.0mag/arcsec2 threshold.
Note (4): Above g*=24.5mag/arcsec-2 threshold
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 31-Jul-2003