J/MNRAS/446/3943 galaxies 2D phot. decompositions in SDSS-DR7 (Meert+, 2015)
A catalogue of 2D photometric decompositions in the SDSS-DR7 spectroscopic main
galaxy sample: preferred models and systematics.
Meert A., Vikram V., Bernardi M.
<Mon. Not. R. Astron. Soc., 446, 3943-3974 (2015)>
=2015MNRAS.446.3943M 2015MNRAS.446.3943M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Models ; Photometry, SDSS ; Morphology
Keywords: galaxies: evolution - galaxies: fundamental parameters -
galaxies: structure
Abstract:
We present a catalogue of 2D, point spread function-corrected de
Vacouleurs, Sersic, de Vacouleurs+Exponential, and Sersic+Exponential
fits of ∼7x105 spectroscopically selected galaxies drawn from the
Sloan Digital Sky Survey (SDSS) Data Release 7. Fits are performed for
the SDSS r band utilizing the fitting routine galfit and analysis
pipeline pymorph. We compare these fits to prior catalogues. Fits are
analysed using a physically motivated flagging system. The flags
suggest that more than 90 percent of two-component fits can be used
for analysis. We show that the fits follow the expected behaviour for
early and late galaxy types. The catalogues provide a robust set of
structural and photometric parameters for future galaxy studies. We
show that some biases remain in the measurements, e.g. the presence of
bars significantly affect the bulge measurements although the bulge
ellipticity may be used to separate barred and non-barred galaxies,
and about 15 percent of bulges of two-component fits are also affected
by resolution. The catalogues are available in electronic format. We
also provide an interface for generating postage stamp images of the
2D model and residual as well as the 1D profile. These images can be
generated for a user-uploaded list of galaxies on demand.
Description:
The data used in this analysis were drawn from the spectroscopic
sample of the Legacy area1 of the Sloan Digital Sky Survey Data
Release 7 (DR7; Abazajian et al. 2009ApJS..182..543A 2009ApJS..182..543A). The
spectroscopic sample provides a well-established sample with
well-defined and tested selection criteria. The criteria are presented
in Strauss et al. (2002AJ....124.1810S 2002AJ....124.1810S).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 51 26 A breakdown of the automated flags characterized
into categories useful for analysis
table5.dat 23 27 The selection criteria used to define the
automated flags
table6.dat 130 21 The selection criteria used to define the
PyMorph flags
table7.dat 87 12 The selection criteria used to define the
PyMorph fit flags
catalog.dat 214 670722 General Catalog Data (band-independent data
used in fitting and analysis)
models_g.dat 388 670722 Best model, Dev, Ser, DevExp, and SerExp model
fit parameters fitted by PyMorph, in g-band
models_r.dat 388 670722 Best model, Dev, Ser, DevExp, and SerExp model
fit parameters fitted by PyMorph, in r-band
models_i.dat 388 670722 Best model, Dev, Ser, DevExp, and SerExp model
fit parameters fitted by PyMorph, in i-band
nparam_g.dat 209 670722 Model-independent measurements fitted by
PyMorph, g-band
nparam_r.dat 209 670722 Model-independent measurements fitted by
PyMorph, r-band
nparam_i.dat 209 670722 Model-independent measurements fitted by
PyMorph, i-band
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
Byte-by-byte Description of file: table*.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Flag Flag bit (1)
4-131 A128 --- Text Explanation of the flag
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Note (1): The first two groups (10-13 and 1-19) can be used for analysis of
total fits. When examining the subcomponents, consideration should be given
as to exactly which groups of fits should be included.
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID Assigned unique galaxy id number (galnum)
8- 25 I18 --- objID Unique SDSS photometric object ID
27- 30 A4 --- --- [SDSS]
32- 50 A19 --- SDSS SDSS IAU designation of the source
(JHHMMSS.ss+DDMMSS.s)
52- 53 I2 --- badflag SDSS photometric pipeline flags SATURATED,
BRIGHT, EDGE, NODEBLEND, CHILD, and
DEBLENDED AS PSF
55 I1 --- Nchild [0] Number of child sources deblended by
the SDSS
57 I1 --- Mode [1/4] Mode (1)
59- 62 I4 --- run SDSS run number
64- 66 I3 --- rerun SDSS rerun number
68 I1 --- camCol SDSS camCol number
70- 72 I3 --- field SDSS field number
74- 77 I4 --- obj SDSS object number
79- 82 I4 --- stripe SDSS stripe number
84- 90 I7 arcsec startmu SDSS starting mu for the observation of
the chunk
92-109 I18 --- specobjid Unique SDSS spectroscopic id number
111-114 I4 --- Plate SDSS plate number
116-120 I5 MJD MJD SDSS MJD of observation
122-124 I3 --- Fiber SDSS Fiber number
126-135 F10.6 deg RAdeg Right ascension (J2000)
137-146 F10.6 deg DEdeg Declination (J2000)
148-155 F8.6 --- z Redshift of the galaxy
157-168 F12.6 km/s sigma ?=-9999 SDSS measured velocity dispersion
170-181 F12.6 km/s e_sigma ?=-9999 rms uncertainty on sigma
183-191 F9.6 --- eclass SDSS spectroscopic classification
193-198 F6.3 --- peld ?=-9 Galaxy Zoo debiased probability of
elliptical galaxy (peldebiased)
200-205 F6.3 --- pcsd ?=-9 Galaxy Zoo Debiased Probability of
spiral galaxy (pcsdebiased)
207-208 I2 --- NS [0/1]?=-9 The raw Galaxy Zoo votes for
spiral type
210-211 I2 --- NE [0/1]?=-9 The raw Galaxy Zoo votes for
elliptical type
213-214 I2 --- NU [0/1]?=-9 The raw Galaxy Zoo votes for
uncertain type
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Note (1): Mode as follows:
1 = primary
2 = secondary
3 = family object
4 = outside chunk boundary
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Byte-by-byte Description of file: models_g.dat models_r.dat models_i.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 mag mtot Total fitted apparent magnitude
12- 15 I4 mag maper ?=-999 Total aperture magnitude
17- 28 E12.6 --- B/T B/T (bulge-to-total light ratio)
of the fit
30- 41 E12.6 arcsec rtot Half-light radius of the total fit
43- 53 F11.6 --- b/atot Axis ratio (semi-minor/semi-major)
of the total fit
56- 59 I4 --- BTaper ?=-999 Bulge aperture magnitude
61- 68 F8.3 pix xctrB ?=-999 Bulge x centre
70- 78 F9.3 pix e_xctrB ?=-999 rms uncertainty on xctrB
80- 87 F8.3 pix yctrB ?=-999 Bulge y centre
89- 97 F9.3 pix e_yctrB ?=-999 rms uncertainty on yctrB
99-106 F8.3 mag mB ?=-999 Bulge magnitude
108-116 F9.3 mag e_mB ?=-999 rms uncertainty on mB
118-125 F8.3 arcsec rB ?=-999 Bulge half-light radius
127-135 F9.3 arcsec e_rB ?=-999 rms uncertainty on rB
138-141 I4 --- nB ?=-999 Bulge Sersic index
143-151 F9.3 --- e_nB ?=-999 rms uncertainty on nB
153-160 F8.3 --- b/aB ?=-999 Bulge axis ratio b/a
162-170 F9.3 --- e_b/aB ?=-999 rms uncertainty on b/sB
172-179 F8.3 deg PAB ?=-999 Bulge position angle
181-189 F9.3 deg e_PAB ?=-999 rms uncertainty on PAB
191-198 F8.3 pix xctrD ?=-999 Disk x centre
200-208 F9.3 pix e_xctrD ?=-999 rms uncertainty on xctrD
210-217 F8.3 pix yctrD ?=-999 Disk y centre
219-227 F9.3 pix e_yctrD ?=-999 rms uncertainty on yctrD
229-236 F8.3 mag mD ?=-999 Disk magnitude
238-246 F9.3 mag e_mD ?=-999 rms uncertainty on mD
248-256 F9.3 arcsec rD ?=-999 Disk half-light radius
258-266 F9.3 arcsec e_rD ?=-999 rms uncertainty on rD
269-272 I4 --- nD ?=-999 Disk Sersic index
274-282 F9.3 --- e_nD ?=-999 rms uncertainty on nD
284-291 F8.3 --- b/aD ?=-999 Disk axis ratio b/a
293-301 F9.3 --- e_b/aD ?=-999 rms uncertainty on b/aD
303-310 F8.3 deg PAD ?=-999 Disk position angle
312-320 F9.3 deg e_PAD ?=-999 rms uncertainty on PAD
322-330 F9.4 mag/arcsec+2 GalSky PyMorph sky brightness
332-342 F11.4 mag/arcsec+2 e_GalSky []?=-999 rms uncertainty on GalSky
344-355 E12.6 --- chi2nu ?=-999 χ2/DOF value
357-364 I8 --- Fflag Primary quality flag (in table1.dat)
366-374 I9 --- Aflag Intermediate, visually calibrated,
automated flag (in table5.dat)
376-382 I7 --- Pyflag PyMorph run flag (in table6.dat)
384-388 I5 --- pyfflag PyMorph fit flag (in table7.dat)
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Byte-by-byte Description of file: nparam_g.dat nparam_r.dat nparam_i.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 mag SexMag SExtractor magnitude
11- 20 F10.4 mag e_SexMag ?=-999 rms uncertainty on SexMag
22- 30 F9.4 arcsec SexHrad SExtractor half-light radius
32- 40 F9.4 mag/arcsec+2 SexSky SExtractor sky brightness
42 I1 --- Ntarget Number neighbour sources fitted with
Ser profiles
44 I1 --- Nneighb Number neighbour sources fitted with
Ser profiles
47- 50 I4 arcsec AperRad ?=-999 Aperture radius
52- 63 E12.6 --- C Concentration parameter
65- 76 E12.6 --- e_C ?=-999 rms uncertainty on C
78- 89 E12.6 --- A Asymmetry parameter
91-102 E12.6 --- e_A ?=-999 rms uncertainty on A
104-115 E12.6 --- S Smoothness parameter
117-128 E12.6 --- e_S ?=-999 rms uncertainty on S
130-141 E12.6 --- G Gini coefficient
143-154 E12.6 --- M20 M20 value
156-163 F8.6 mag ext SDSS-provided galactic extinction
165-171 F7.4 mag MOD Calculated distance modulus
173-180 F8.6 kpc/arcsec Scale Angular scale
182-193 E12.6 Mpc+3 Vmax Volume used for Vmax corrections
196-199 I4 --- SN ?=-999 Average S/N per pixel inside
the half-light radius
201-209 F9.4 mag kcorr k-correction calculated using the
SDSS model magnitudes
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History:
Copied at http://www.physics.upenn.edu/~ameert/SDSS_PhotDec/download/
(End) Patricia Vannier [CDS] 21-Jul-2015