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J/A+A/486/85 Abell 496 low-luminosity early-type galaxies  (Chilingarian+, 2008)

Kinematics and stellar populations of low-luminosity early-type galaxies in the Abell 496 cluster. Chilingarian I.V., Cayatte V., Durret F., Adami C., Balkowski C., Chemin L., Lagana T.F., Prugniel P. <Astron. Astrophys., 486, 85-97 (2008)> =2008A&A...486...85C
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry Keywords: galaxies: elliptical and lenticular, cD - galaxies: dwarf - galaxies: clusters: individual: Abell 496 - galaxies: kinematics and dynamics - galaxies: stellar content - galaxies: fundamental parameters Abstract: The morphology and stellar populations of low-luminosity early-type galaxies in clusters have until now been limited to a few relatively nearby clusters such as Virgo or Fornax. Scenarii for the formation and evolution of dwarf galaxies in clusters are therefore not well constrained. We investigate here the morphology and stellar populations of low-luminosity galaxies in the relaxed richness class 1 cluster Abell 496 (z=0.0330). Deep multiband imaging obtained with the CFHT Megacam allowed us to select a sample of faint galaxies, defined here as objects with magnitudes 18<r'<22mag within a 1.2arcsec fibre (-18.8<MB←15.1mag). We observed 118 galaxies spectroscopically with the ESO VLT FLAMES/Giraffe spectrograph with a resolving power R=6300. We present structural analysis and colour maps for the 48 galaxies belonging to the cluster. We fit the spectra of 46 objects with PEGASE. HR synthetic spectra to estimate the ages, metallicities, and velocity dispersions. We estimated possible biases by similarly analysing spectra of ∼1200 early-type galaxies from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6). We computed values of α/Fe abundance ratios from the measurements of Lick indices. We briefly discuss effects of the fixed aperture size on the measurements. Description: We obtained images with the Canada France Hawaii Telescope with the Megacam camera in the fall of 2003 (program 03BF12, P.I. V. Cayatte). Megacam covers a field of 1°x1° on the sky, with a pixel size of 0.187x0.187arcsec2. We obtained deep images in the u*, g', r', and i' filters. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 99 48 B band absolute magnitudes, morphological classification, detection of embedded structures, and total magnitudes in 4 CFHT bands for 48 Abell 496 galaxies tablea2.dat 70 48 Projected distances, relative radial velocities with respect to the cluster centre, and structural parameters tablea3.dat 87 48 *Selected Lick indices, values of derived values of [Mg/Fe] using SSP models by Thomas et al. (2003MNRAS.339..897T) and brief comments concerning structures seen in colour maps
Note on tablea3.dat: For the 2 objects marked A1 and A2, no spectral fit was possible.
See also: J/A+AS/139/525 : Abell 496 heliocentric velocities (Durret+, 1999) J/A+AS/139/559 : Abell 496 photometric catalogue (Slezak+, 1999) J/A+AS/140/155 : Abell 496 gri photometry (Moretti+, 1999) J/A+A/393/439 : Catalogue of galaxies towards Abell 496 (Durret+, 2002) Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 2 A2 --- [CCD2008] Sequential number (G1) 4- 9 A6 --- --- [ACO496] 10- 28 A19 --- ACO496 ACO496 designation ( 30- 35 F6.2 mag BMAG Absolute B magnitude 37- 44 A8 --- SpT Spectral type 46- 55 A10 --- embStr ?=- Embedded structures 57- 61 F5.2 mag u*mag Total u* magnitude 63- 66 F4.2 mag e_u*mag rms uncertainty on u*mag 68- 72 F5.2 mag g'mag Total g' magnitude 74- 77 F4.2 mag e_g'mag rms uncertainty on g'mag 79- 83 F5.2 mag r'mag Total r' magnitude 85- 88 F4.2 mag e_r'mag rms uncertainty on r'mag 90- 94 F5.2 mag i'mag Total i' magnitude 96- 99 F4.2 mag e_i'mag rms uncertainty on i'mag
Byte-by-byte Description of file: tablea2.dat
Bytes Format Units Label Explanations
1- 2 A2 --- [CCD2008] Sequential number (G1) 4- 7 I4 arcsec Dproj Projected distance from central cD galaxy 9- 13 I5 km/s DV Velocity difference (RV-V(A496)) 15- 18 F4.2 arcsec reff Effective radius 20- 23 F4.2 arcsec e_reff rms uncertainty on reff 25- 29 F5.2 mag/arcsec+2 <mueff> Mean effective surface brightness in B within 1reff 31- 34 F4.2 mag/arcsec+2 e_<mueff> rms uncertainty on <mueff> 36- 40 I5 km/s RV Radial velocity 42- 43 I2 km/s e_RV rms uncertainty on RV 45- 47 I3 km/s sigma ? Best-fitting velocity dispersion 49 I1 km/s e_sigma ? rms uncertainty on sigma 51- 54 F4.1 Gyr tau ? Best-fitting SSP-equivalent age 56- 58 F3.1 Gyr e_tau ? rms uncertainty on t 60- 64 F5.2 --- Z ? Best-fitting metallicity 66- 69 F4.2 --- e_Z ? rms uncertainty on Z 70 A1 --- Note [a] Note (1)
Note (1): a = The values of reff and <mueff> for G-20 in this table are strongly discrepant with those presented in Chilingarian et al. (2007A&A...466L..21C) measured on HST WFPC2, because here we did not take into account seeing quality of our ground-based CFHT observations.
Byte-by-byte Description of file: tablea3.dat
Bytes Format Units Label Explanations
1- 2 A2 --- [CCD2008] Sequential number (G1) 4- 9 F6.2 0.1nm Fe5015 ? Fe5015 Lick index 11- 14 F4.2 0.1nm e_Fe5015 ? rms uncertainty on Fe5015 16- 19 F4.2 0.1nm MgB ? MgB Lick index 21- 24 F4.2 0.1nm e_MgB ? rms uncertainty on MgB 26- 29 F4.2 0.1nm Fe5270 ? Fe5270 Lick index 31- 34 F4.2 0.1nm e_Fe5270 ? rms uncertainty on Fe5270 36- 39 F4.2 0.1nm Fe5335 ? Fe5335 Lick index 41- 44 F4.2 0.1nm e_Fe5335 ? rms uncertainty on Fe5335 46- 49 F4.2 0.1nm Fe5406 ? F35406 Lick index 51- 54 F4.2 0.1nm e_Fe5406 ? rms uncertainty on Fe5406 56- 60 F5.2 --- [Mg/Fe] ? Abundance [Mg/Fe] 62- 65 F4.2 --- e_[Mg/Fe] ? rms uncertainty on [Mg/Fe] 67- 87 A21 --- Com Comments
Global notes: Note (G1): [CCD2008] G-NN in Simbad.
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Sep-2008
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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