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For refcode 1996AJ....111.1889B:
Retrieve 57 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
1996AJ....111.1889B THE CENTERS OF EARLY-TYPE GALAXIES WITH HST. II. EMPIRICAL MODELS AND STRUCTURAL PARAMETERS YONG-IK BYUH Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, Hawaii 96822 CARL J. GRlLLMAIR UCO/Lick Observatories, University of California, Santa Cruz, California 95064 S. M. FABER UCO/Lick Observatories, Board of Studies in Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, California 95064 EDWARD A. AJHAR Kitt Peak National Observatory, National Optical Astronomy Observatories, P. O. Box 26732, Tucson, Arizona 85726 ALAN DRESSLER The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara St., Pasadena, California 91101 JOHN KORMENDY Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, Hawaii 96822 TOD R. LAUER Kitt Peak National Observatory, National Optical Astronomy Observatories,3 P. O. Box 26732, Tucson, Arizona 85726 DOUGLAS RICHSTONE Department of Astronomy, University of Michigan, Ann Arbor, Michigan 48109 SCOTT TREMAINE Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George St., Toronto, M5S 3H8, Canada Received 1995 December 5; revised 1996 February 13 ABSTRACT We present a set of structural parameters for the central parts of 57 early-type galaxies observed with the Planetary Camera of the Hubble Space Telescope. These parameters are based on a new empirical law that successfully characterizes the centers of early-type galaxies. This empirical law assumes that the surface brightness profile is a combination of two power laws with different slopes {gamma} and {beta} for the inner and outer regions. Conventional structural parameters such as core radius and central surface brightness are replaced by break radius r_b_, where the transition between power-law slopes takes place, and surface brightness {mu}_b_ at that radius. An additional parameter {alpha} describes the sharpness of the break. The structural parameters are derived using a X^2^ minimization process applied to the mean surface brightness profiles. The resulting model profiles generally give very good agreement to the observed profiles out to the radius of ~10" imaged by the Planetary Camera. Exceptions include galaxies which depart from pure power laws at large radius, those with strong nuclear components, and galaxies partly obscured by dust. The uncertainties in the derived parameters are estimated using Monte Carlo simulations which test the stability of solutions in the face of photon noise and the effects of the deconvolution process. The covariance of the structural parameters is examined by computing contours of constant X^2^ in multi-dimensional parameter space.
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