Multicolor photometric properties of six early-type galaxies *
F. Ferrari and
Received 2 March 1999 / Accepted 19 July 1999
We present BVRI CCD surface photometry for 4 elliptical and 2 S0 galaxies that show bright emission lines in their nuclear spectra. We obtained isophote maps, luminosity profiles, and basic photometric parameters. We also obtained continuum subtracted H+[NII] images for 5 galaxies in our sample, but only in two of them, NGC 6858 and ESO 185-54, we detected emission gas. We used the standard technique of ellipse fitting to determine the radial variation of surface brightness, color, ellipticity, position angle and the fourth order Fourier coefficient of the deviations from elliptical shape to look for isophotal twists, color gradients and fine structure variations. We have fitted an Sérsic law to the light profiles, finding that it provides a better fit to the light profiles of the ellipticals than the traditional law. However, this law does not provide a good fit for SO galaxies.
Key words: galaxies: elliptical and lenticular, cD galaxies: photometry galaxies: structure
* Based on observations made at Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation, and at the Observatório do Pico dos Dias, CNPq/Laboratório Nacional de Astrofísica, Brazil.
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© European Southern Observatory (ESO) 1999
Online publication: October 4, 1999