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J/ApJ/787/102      Isophotal shapes of early-type galaxies      (Chaware+, 2014)

Isophotal shapes of early-type galaxies to very faint levels. Chaware L., Cannon R., Kembhavi A.K., Mahabal A., Pandey S.K. <Astrophys. J., 787, 102 (2014)> =2014ApJ...787..102C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Photometry, SDSS Keywords: galaxies: elliptical and lenticular, cD - galaxies: photometry - galaxies: statistics - galaxies: structure Abstract: We report on a study of the isophotal shapes of early-type galaxies to very faint levels, reaching ∼0.1% of the sky brightness. The galaxies are from the Large Format Camera (LFC) fields obtained using the Palomar 5 m Hale Telescope, with integrated exposures ranging from 1 to 4 hr in the Sloan Digital Sky Survey r, i, and z bands. The shapes of isophotes of early-type galaxies are important, as they are correlated with the physical properties of the galaxies and are influenced by galaxy formation processes. In this paper, we report on a sample of 132 E and SO galaxies in one LFC field. We have redshifts for 53 of these, obtained using AAOmega on the Anglo-Australian Telescope. The shapes of early-type galaxies often vary with radius. We derive average values of isophotal shape parameters in four different radial bins along the semi-major axis in each galaxy. We obtain empirical fitting formulae for the probability distribution of the isophotal parameters in each bin and investigate for possible correlations with other global properties of the galaxies. Our main finding is that the isophotal shapes of the inner regions are statistically different from those in the outer regions. This suggests that the outer and inner parts of early-type galaxies have evolved somewhat independently. Description: The imaging data were originally obtained as part of a faint quasar survey using the Large Format Camera (LFC) on the 5 m Hale Telescope at Mount Palomar Observatory, with integrated exposures ranging from 1 to 4 hr in r, i, and z filters. The LFC is a mosaic of six 2048x4096 pixel CCDs, mounted at the prime focus of the Hale Telescope. The fields targeted were those of known SDSS high-redshift (z>5) quasars in order to look for a local over-density of quasars (Mahabal et al. 2005ApJ...634L...9M). We obtained reduced images, which were bias subtracted, flat fielded, and processed to remove cosmic rays as a part of the original program. The deep LFC images have excellent signal-to-noise ratio (S/N), permitting us to examine faint features, including the outermost extensions of the galaxies, down to ∼0.1% of the sky brightness. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 141 132 Basic parameters of the sample of early-type galaxies table3.dat 64 528 Derived parameters for a sample of the LFC galaxies
See also: II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009) J/MNRAS/327/1004 : Early-type galaxy parameters (Blakeslee+, 2001) J/AJ/125/1817 : SDSS Early-Type Galaxies Catalog (Bernardi+, 2003) J/AJ/129/2138 : Centers of early-type galaxies with HST (Lauer+, 2005) J/MNRAS/460/4492 : Nearby early-type galaxies catalog (Dabringhausen+, 2016) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 A3 --- --- [LFC] 5- 8 I4 --- LFC SExtractor identifier from this paper (LFC NNNN) 10- 27 I18 --- SDSS SDSS identifier (1) 29- 40 F12.8 deg RAdeg Right Ascension in decimal degrees (J2000) (1) 42- 52 F11.8 deg DEdeg Declination in decimal degrees (J2000) (1) 54- 58 F5.2 mag umag SDSS u band magnitude (1) 60- 64 F5.2 mag e_umag Uncertainty in umag (1) 66- 70 F5.2 mag gmag SDSS g band magnitude (1) 72- 75 F4.2 mag e_gmag Uncertainty in gmag (1) 77- 81 F5.2 mag rmag SDSS r band magnitude (1) 83- 86 F4.2 mag e_rmag Uncertainty in rmag (1) 88- 92 F5.2 mag imag SDSS i band magnitude (1) 94- 97 F4.2 mag e_imag Uncertainty in imag (1) 99-103 F5.2 mag zmag SDSS z band magnitude (1) 105-108 F4.2 mag e_zmag Uncertainty in zmag (1) 110-113 F4.2 arcsec R50 Petrosian half-light radius (1) 115-118 F4.2 arcsec e_R50 Uncertainty in R50 (1) 120-124 F5.2 arcsec MajAxis Semi-major axis (2) 126-130 F5.2 mag/arcsec2 mui The i band surface brightness (2) 132-135 F4.2 mag/arcsec2 e_mui Uncertainty in mui 137-141 F5.2 --- SNR Signal-to-Noise ratio (2)
Note (1): Obtained from the PhotoObjAll table of the SDSS DR7 photometric catalog (Abazajian et al. 2009ApJS..182..543A, Cat. II/294) where all magnitudes are extinction corrected Petrosian magnitudes. Note (2): Of the outermost isophote in which ellipse can be fitted (see Section 4).
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 3 A3 --- --- [LFC] 5- 8 I4 --- LFC SExtractor identifier from this paper (LFC NNNN) (1) 10- 13 F4.2 --- B/T Bulge-to-total luminosity ratio 15- 23 E9.2 --- <a3/a> ? Mean a3/a isophotal parameter 25- 32 E8.2 --- e_<a3/a> ? Uncertainty in <a3/a> 34- 42 E9.2 --- <a4/a> ? Mean a4/a isophotal parameter 44- 51 E8.2 --- e_<a4/a> ? Uncertainty in <a4/a> 53- 57 F5.3 --- <epsilon> ? Mean ellipticity 59- 64 F6.4 --- e_<epsilon> ? Uncertainty in <epsilon>
Note (1): Each source has four entries on subsequent rows that give the values in Regions 1-4 respectively. These data are not available for all regions in every galaxy (see Section 3).
History: From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 28-Jun-2017
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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