J/MNRAS/377/787 SDSS Luminous Red Galaxies (Barber+, 2007)
Properties of Luminous Red Galaxies in the Sloan Digital Sky Survey.
Barber T., Meiksin A., Murphy T.
<Mon. Not. R. Astron. Soc. 377, 787 (2007)>
=2007MNRAS.377..787B 2007MNRAS.377..787B
ADC_Keywords: Galaxies, photometry ; Photometry, SDSS
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: formation - galaxies: fundamental parameters -
galaxies: stellar content
Description:
The data are taken from the Luminous Red Galaxy sample of the Sloan
Digital Sky Survey Data Release 4. From the SDSS spectra we compute
the five indices Hbeta, HgammaF, Dn(4000), [MgFe]', [Mg1Fe]'. These
are matched indices from a synthetic library of spectra containing
31000 different star formation scenarios. From this we can infer
probability distributions for a number of properties, such as age,
metallicity, etc. The results are presented here as the 5th, 16th,
50th (median), 86th and 95th percentiles of the relevant distribution.
The 4391 LRG properties presented here are chosen from the redshift
range 0.15<z<0.4 and require all 5 of the above indices to have
well-measured values (i.e. no contamination from skylines, bad pixels)
Also given are a number of properties that come directly from the SDSS
database, such as redshift, velocity dispersion etc. For the
luminosity distance calculation (and subsequent mass estimates), we
assume a FRW metric, with omegam=0.25, omegalambda=0.75 and
H0=73km/s/Mpc.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
lrgs.dat 1120 4391 Luminous Red Galaxies (LRG) derived parameters
--------------------------------------------------------------------------------
See also:
J/MNRAS/330/1 : HST observations of Extremely Red Objects (Smith+, 2002)
J/MNRAS/354/L25 : MgII absorbers in SDSS QSOs (Bouche+, 2004)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: lrgs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SDSS SDSS spectrum number
20- 24 I5 d MJD JD-2400000.5 date of observation
26- 29 I4 --- Plate Plate Number
31- 34 I4 --- Tile Tile Number
36- 38 I3 --- Fiber Fibre number
40- 51 E12.6 deg RAdeg Right ascension (J2000)
53- 64 E12.6 deg DEdeg Declination (J2000)
66- 75 E10.4 mag E(B-V) Foreground dust extinction
77- 88 E12.6 mag AV Foreground extinction in the V-band
90- 101 E12.6 --- z Redshift of galaxy
103- 114 E12.6 --- e_z Error on redshift
116- 127 E12.6 --- zconf Redshift confidence
129- 140 E12.6 Mpc Dist Luminosity distance
142- 153 E12.6 Myr tlb Lookback time at observation
155- 164 E10.4 km/s sigma Velocity dispersion
166- 175 E10.4 km/s e_sigma Error on velocity dispersion
177- 188 E12.6 --- S/N0 Median S/N in g'
190- 201 E12.6 --- S/N1 Median S/N in r'
203- 214 E12.6 --- S/N2 Median S/N in i'
216- 227 E12.6 --- S/N Median S/N of spectrum
229- 240 E12.6 mag umagfib Fiber magnitude in SDSS u'
242- 253 E12.6 mag umag Photometric magnitude in SDSS u'
255- 266 E12.6 mag Au Galactic extinction in SDSS u'
268- 279 E12.6 mag gmagfib Fiber magnitude in SDSS g'
281- 292 E12.6 mag gmag Photometric magnitude in SDSS g'
294- 305 E12.6 mag Ag Galactic extinction in SDSS g'
307- 318 E12.6 mag rmagfib Fiber magnitude in SDSS r'
320- 331 E12.6 mag rmag Photometric magnitude in SDSS r'
333- 344 E12.6 mag Ar Galactic extinction in SDSS r'
346- 357 E12.6 mag imagfib Fiber magnitude in SDSS i'
359- 370 E12.6 mag imag Photometric magnitude in SDSS i'
372- 383 E12.6 mag Ai Galactic extinction in SDSS i'
385- 396 E12.6 mag zmagfib Fiber magnitude in SDSS z'
398- 409 E12.6 mag zmag Photometric magnitude in SDSS z'
411- 422 E12.6 mag Az Galactic extinction in SDSS z'
424- 425 I2 --- ndoflick Number of indices used to fit models
427- 438 E12.6 --- chi2lick Best fitting chi-square from indices
440- 444 I5 --- ndofsp Number of dof in spectrum (pixels)
446- 457 E12.6 --- chi2sp chi-sq from spectrum best lick model
459- 470 E12.6 10+6yr Age Light-weighted age of best fit
472- 483 E12.6 --- Z Light-weighted metallicity of best fit
485- 496 E12.6 [solMass] logMass log(mass/m{sol}) of best fit
498- 509 E12.6 10+6yr age05 5% of Light-weighted age PDF (1)
511- 522 E12.6 10+6yr age16 16% of Light-weighted age PDF (1)
524- 535 E12.6 10+6yr age50 50% of Light-weighted age PDF (1)
537- 548 E12.6 10+6yr age84 84% of Light-weighted age PDF (1)
550- 561 E12.6 10+6yr age95 95% of Light-weighted age PDF (1)
563- 574 E12.6 10+6yr tform05 5% of formation time PDF (1)
576- 587 E12.6 10+6yr tform16 16% of formation time PDF (1)
589- 600 E12.6 10+6yr tform50 50% of formation time PDF (1)
602- 613 E12.6 10+6yr tform84 84% of formation time PDF (1)
615- 626 E12.6 10+6yr tform95 95% of formation time PDF (1)
628- 639 E12.6 10+6yr t50-05 5% of time 50% of mass in place PDF (1)
641- 652 E12.6 10+6yr t50-16 16% of time 50% of mass in place PDF (1)
654- 665 E12.6 10+6yr t50-50 50% of time 50% of mass in place PDF (1)
667- 678 E12.6 10+6yr t50-84 84% of time 50% of mass in place PDF (1)
680- 691 E12.6 10+6yr t50-95 95% of time 50% of mass in place PDF (1)
693- 704 E12.6 10+6yr t80-05 5% of time 80% of mass in place PDF (1)
706- 717 E12.6 10+6yr t80-16 16% of time 80% of mass in place PDF (1)
719- 730 E12.6 10+6yr t80-50 50% of time 80% of mass in place PDF (1)
732- 743 E12.6 10+6yr t80-84 84% of time 80% of mass in place PDF (1)
745- 756 E12.6 10+6yr t80-95 95% of time 80% of mass in place PDF (1)
758- 769 E12.6 --- Z05 5% of Light-weighted Z PDF (1)
771- 782 E12.6 --- Z16 16% of Light-weighted Z PDF (1)
784- 795 E12.6 --- Z50 50% of Light-weighted Z PDF (1)
797- 808 E12.6 --- Z84 84% of Light-weighted Z PDF (1)
810- 821 E12.6 --- Z95 95% of Light-weighted Z PDF (1)
823- 834 E12.6 [solMass] mass05 5% of log10(mass/msol) PDF (1)
836- 847 E12.6 [solMass] mass16 16% of log10(mass/msol) PDF (1)
849- 860 E12.6 [solMass] mass50 50% of log10(mass/msol) PDF (1)
862- 873 E12.6 [solMass] mass84 84% of log10(mass/msol) PDF (1)
875- 886 E12.6 [solMass] mass95 95% of log10(mass/msol) PDF (1)
888- 899 E12.6 mag AV05 5% of V-band extinction PDF (1)
901- 912 E12.6 mag AV16 16% of V-band extinction PDF (1)
914- 925 E12.6 mag AV50 50% of V-band extinction PDF (1)
927- 938 E12.6 mag AV84 84% of V-band extinction PDF (1)
940- 951 E12.6 mag AV95 95% of V-band extinction PDF (1)
953- 964 E12.6 Gyr-1 gamma05 5% of SFR decay factor PDF (1)
966- 977 E12.6 Gyr-1 gamma16 16% of SFR decay factor PDF (1)
979- 990 E12.6 Gyr-1 gamma50 50% of SFR decay factor PDF (1)
992-1003 E12.6 Gyr-1 gamma84 84% of SFR decay factor PDF (1)
1005-1016 E12.6 Gyr-1 gamma95 95% of SFR decay factor PDF (1)
1018-1029 E12.6 --- mfrac05 5% of fraction of burst mass PDF (1)
1031-1042 E12.6 --- mfrac16 16% of fraction of burst mass PDF (1)
1044-1055 E12.6 --- mfrac50 50% of fraction of burst mass PDF (1)
1057-1068 E12.6 --- mfrac84 84% of fraction of burst mass PDF (1)
1070-1081 E12.6 --- mfrac95 95% of fraction of burst mass PDF (1)
1083-1094 E12.6 --- pburst2 Probability of burst in last 2 Gyr
1096-1107 E12.6 --- pburst4 Probability of burst in last 4 Gyr
1109-1120 E12.6 --- pburst6 Probability of burst in last 6 Gyr
--------------------------------------------------------------------------------
Note (1): PDF = robability Density Function
--------------------------------------------------------------------------------
Acknowledgements:
Tom Barber, barber(at)hep.phy.cam.ac.uk
(End) Tom Barber [ROE], Patricia Vannier [CDS] 22-Mar-2007