J/AJ/128/163 Galaxy morphological classification (Lotz+, 2004)
A new nonparametric approach to galaxy morphological classification.
Lotz J.M., Primack J., Madau P.
<Astron. J., 128, 163-182 (2004)>
=2004AJ....128..163L 2004AJ....128..163L
ADC_Keywords: Morphology ; Galaxies, peculiar
Keywords: galaxies: fundamental parameters - galaxies: high-redshift -
galaxies: peculiar - galaxies: structure
Abstract:
We present two new nonparametric methods for quantifying galaxy
morphology: the relative distribution of the galaxy pixel flux values
(the Gini coefficient or G) and the second-order moment of the
brightest 20% of the galaxy's flux (M20). We test the robustness of
G and M20 to decreasing signal-to-noise ratio (S/N) and spatial
resolution and find that both measures are reliable to within 10% for
images with average S/N per pixel greater than 2 and resolutions
better than 1000 and 500pc, respectively. We have measured G and
M20, as well as concentration (C), asymmetry (A), and clumpiness (S)
in the rest-frame near-ultraviolet/optical wavelengths for 148 bright
local "normal" Hubble-type galaxies (E-Sd) galaxies, 22 dwarf
irregulars, and 73 0.05<z<0.25 ultraluminous infrared galaxies
(ULIRGs).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 108 105 Frei Galaxy Catalog (1996AJ....111..174F 1996AJ....111..174F)
table3.dat 140 54 SDSS u-selected Catalog (2003AJ....126.2081A 2003AJ....126.2081A)
notes.dat 103 19 Notes
table5.dat 90 73 Borne et al. (2000ApJ...529L..77B 2000ApJ...529L..77B) ULIRG HST Survey
table7.dat 80 49 HDF-N Lyman Break Galaxies
--------------------------------------------------------------------------------
See also:
J/ApJS/107/1 : Morphologies of distant galaxies II (Abraham+ 1996)
J/AJ/126/2579 : SDSS quasar catalog. II. First data release (Schneider+, 2003)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Galaxy name (1)
10 A1 --- n_Name [4] Indicates also observed by SDSS DR1
(also in Table 3)
12- 26 A15 --- Type The Sandage & Bedke (1994) type (2)
28- 32 F5.1 mag BMag Absolute B-band magnitude (RC3, Cat. VII/155,
apparent magnitude minus m-M)
34- 38 F5.2 mag m-M Distance modulus
40- 41 I2 --- n_m-M Note on m-M, see file notes.dat
43- 46 F4.1 --- S/N-B BJ or Gunn g-band signal-to-noise ratio
48- 51 F4.2 --- CB BJ or Gunn g-band concentration
53- 57 F5.2 --- AB BJ or Gunn g-band asymmetry
59- 64 F6.3 --- SB BJ or Gunn g-band clumpiness
66- 69 F4.2 --- GB BJ or Gunn g-band Gini coefficient
71- 75 F5.2 --- M20B Second-order moment of brightest 20% BJ or
Gunn g-band flux
77- 80 F4.1 --- S/N-R R or Gunn r-band signal-to-noise ratio
82- 85 F4.2 --- CR R or Gunn r-band concentration
87- 91 F5.2 --- AR R or Gunn r-band asymmetry
93- 97 F5.2 --- SR R or Gunn r-band clumpiness
99-102 F4.2 --- GR R or Gunn r-band Gini coefficient
104-108 F5.2 --- M20R Second-order moment of brightest 20% R- or
Gunn r-band flux
--------------------------------------------------------------------------------
Note (1): Frei et al. (1996AJ....111..174F 1996AJ....111..174F) catalog; see also
http://www.astro.princeton.edu/~frei/catalog.html.
Note (2): Sandage, A., & Bedke, J.: 1994, The Carnegie Atlas of Galaxies,
Volume 1 (Washington: Carnegie Inst.)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Galaxy name (1)
10 A1 --- n_Name [4] Indicates also observed by Frei et al.,
1996AJ....111..174F 1996AJ....111..174F (also in Table 2)
12- 24 A13 --- MType The Sandage & Bedke (1994) type (2)
26- 30 F5.1 mag BMag Absolute B-band magnitude (RC3, Cat. VII/155,
apparent magnitude minus m-M)
32- 36 F5.2 mag m-M Distance modulus
38- 39 I2 --- n_m-M Note on m-M
41- 43 F3.1 --- S/N-u SDSS u-band signal-to-noise ratio
45- 48 F4.2 --- Cu SDSS u-band concentration
50- 54 F5.2 --- Au SDSS u-band asymmetry
56- 60 F5.2 --- Su SDSS u-band clumpiness
62- 65 F4.2 --- Gu SDSS u-band Gini coefficient
67- 72 F6.3 --- M20u Second-order moment of brightest 20% u-band flux
74- 77 F4.1 --- S/N-g SDSS g-band signal-to-noise ratio
79- 82 F4.2 --- Cg SDSS g-band concentration
84- 88 F5.2 --- Ag SDSS g-band asymmetry
90- 94 F5.2 --- Sg SDSS g-band clumpiness
96- 99 F4.2 --- Gg SDSS g-band Gini coefficient
101-105 F5.2 --- M20g Second-order moment of brightest 20% g-band flux
107-112 F6.3 --- S/N-r SDSS r-band signal-to-noise ratio
114-117 F4.2 --- Cr SDSS r-band concentration
119-123 F5.2 --- Ar SDSS r-band asymmetry
125-129 F5.2 --- Sr SDSS r-band clumpiness
131-134 F4.2 --- Gr SDSS r-band Gini coefficient
136-140 F5.2 --- M20r Second-order moment of brightest 20% r-band flux
--------------------------------------------------------------------------------
Note (1): Abazajian et al. (2003AJ....126.2081A 2003AJ....126.2081A) catalog;
http://www.sdss.org/dr1.
Note (2): Sandage, A., & Bedke, J.: 1994, The Carnegie Atlas of Galaxies,
Volume 1 (Washington: Carnegie Inst.)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: notes.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Note Note number
4-103 A100 --- Text Note and reference
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- Name Galaxy name (1)
18 A1 --- m_Name Multiplicity flag on Name
20- 25 F6.4 --- z NED redshift
27- 28 I2 h RAh Hour of right ascension (J2000)
30- 31 I2 min RAm Minute of right ascension (J2000)
33- 34 I2 s RAs Second of right ascension (J2000)
36 A1 --- DE- Sign of the declination (J2000)
37- 38 I2 deg DEd Degree of declination (J2000)
40- 41 I2 arcmin DEm Arcminute of declination (J2000)
43- 44 I2 arcsec DEs Arcsecond of declination (J2000)
46- 48 F3.1 --- S/N Signal-to-noise ratio
50- 53 F4.2 --- C Concentration
55- 59 F5.2 --- A Asymmetry
61- 64 F4.2 --- S Clumpiness
66- 69 F4.2 --- G Gini coefficient
71- 75 F5.2 --- M20 Second-order moment of brightest 20% flux
77- 90 A14 --- Class Cui et al. (2001AJ....122...63C 2001AJ....122...63C) nuclei
classification (except where starred)
--------------------------------------------------------------------------------
Note (1): Borne et al. (2000ApJ...529L..77B 2000ApJ...529L..77B) catalog;
HST WFPC2 F814W observations.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- HNM Identification number (1)
8- 12 F5.3 --- z Photometric redshift (2)
14 A1 --- f_z [3] Indicates a spectroscopic redshift (3)
16- 17 I2 h RAh Hour of right ascension (J2000)
19- 20 I2 min RAm Minute of right ascension (J2000)
22- 26 F5.2 s RAs Second of right ascension (J2000)
27 A1 --- DE- Sign of the declination (J2000)
28- 29 I2 deg DEd Degree of declination (J2000)
31- 32 I2 arcmin DEm Arcminute of declination (J2000)
34- 37 F4.1 arcsec DEs Arcsecond of declination (J2000)
39- 43 F5.2 mag Hmag The H-band magnitude
45- 49 F5.1 mag BMag Absolute B-band magnitude
51- 54 F4.2 arcsec Rad Petrosian radius
56- 59 F4.1 --- S/N Signal-to-noise ratio
61- 63 F3.1 --- C Concentration
65- 69 F5.2 --- A Asymmetry
71- 74 F4.2 --- G Gini coefficient
76- 80 F5.2 --- M20 Second-order moment of brightest 20% flux
--------------------------------------------------------------------------------
Note (1): M. Dickinson 2003, private communication.
Note (2): See Budavari et al. 2000AJ....120.1588B 2000AJ....120.1588B.
Note (3): See Cohen et al. (2000, Cat. J/ApJ/538/29).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 03-Oct-2005