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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 225839.0, MPI für Astronomie / Publikationen_mpia
Evidence for a new elliptical-galaxy paradigm: Sérsic and core galaxies
Authors:Trujillo, I.; Erwin, Peter; Ramos, A. Asensio; Graham, Alister W.
Date of Publication (YYYY-MM-DD):2004
Title of Journal:The Astronomical Journal
Start Page:1917
End Page:1942
Review Status:not specified
Audience:Not Specified
Abstract / Description:We fitted the surface-brightness profiles of
21 elliptical galaxies using both the
S‚‚eacute;rsic function and a new empirical model
that combines an inner power law with an outer
S‚‚eacute;rsic function. The profiles are
combinations of deconvolved Hubble Space
Telescope (HST) profiles from the literature and
ellipse fits to the full WFPC2 mosaic images and
thus span a radial range from ~0.02" to about
twice the half-light radius. We are able to
accurately fit the entire profiles using either
the S‚‚eacute;rsic function or our new model. In
doing so, we demonstrate that most, if not all,
so-called ``power-law'' galaxies are better
described as ``S‚‚eacute;rsic galaxies''-they are
well modeled by the three-parameter
S‚‚eacute;rsic profile into the limits of HST
resolution-and that ``core'' galaxies are best
understood as consisting of an outer
S‚‚eacute;rsic profile with an inner power-law
cusp, which is a downward deviation from the
inward extrapolation of the S‚‚eacute;rsic
profile. This definition of cores resolves
ambiguities that result when the popular ``Nuker
law'' is fitted to the profiles of ellipticals
and bulges, particularly at lower luminosities.
We also find that using the Nuker law to model
core-galaxy nuclear profiles systematically
overestimates the core radii by factors of
1.5-4.5 and underestimates the inner power-law
slope by ~20%-40% or more.
Free Keywords:Galaxies: Elliptical and Lenticular; cD;
; Galaxies: Fundamental Parameters; Galaxies:
; Nuclei; Galaxies: Photometry; Galaxies:
; Structure
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
External Affiliations:K‚‚ouml;nigstuhl 17, D-69117 Heidelberg, Germany;
AB(Instituto de Astrof‚‚iacute;sica de Canarias,
Calle V‚‚iacute;a L‚‚aacute;ctea s/n, E-38200 La
Laguna, Tenerife, Spain;
<EMAIL>aasensio@ll.iac.es</EMAIL>), AC(Instituto
deAstrof‚‚iacute;sica de Canarias, Calle
V‚‚iacute;a L‚‚aacute;ctea s/n, E-38200 La
Laguna, Tenerife, Spain;
<EMAIL>aasensio@ll.iac.es</EMAIL>), AD(Department
of Astronomy, P.O. Box 112055, University of
Florida, Gainesville, FL 32611;
Identifiers:URL:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi... [ID No:1]
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