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Title

Intracluster light and the extended stellar envelopes of cD galaxies: an analytical description

Author(s)

Seigar, Marc S.;  Graham, Alister W.;  Jerjen, Helmut

Abstract

We have analysed deep R-band images, down to a limiting surface brightness of 26.5 R-mag arcsec−2 (equivalent to ~28 B-mag arcsec−2), of five cD galaxies to determine the shape of the surface brightness profiles of their extended stellar envelopes. Both de Vaucouleurs r 1/4 and Sérsic R1/n models, on their own, provide a poor description of the surface brightness profiles of cD galaxies. This is due to the presence of outer stellar envelopes, thought to have accumulated over the merger history of the central cluster galaxy and also from the tidal stripping of galaxies at larger cluster radii. We therefore simultaneously fit two Sérsic functions to measure the shape of the inner and outer components of the cD galaxies. We show that, for three out of our five galaxies, the surface brightness profiles are best fitted by an inner Sérsic model, with indices n ~ 1 -6, and an outer exponential component. For these systems, the galaxy-to-envelope size ratio is 0.1-0.4 and the contribution of the stellar envelope to the total R-band light (i.e. galaxy + envelope) is around 60-80 per cent (based on extrapolation to a 300 kpc radius). The exceptions are NGC 6173, for which our surface brightness profile modelling is consistent with just a single component (i.e. no envelope) and NGC 4874 which appears to have an envelope with a de Vaucouleurs, rather than exponential, profile.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 378, no. 4 (Jul 2007), pp. 1575-1588

Publication year

2007

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

cD;  Elliptical and lenticular galaxies;  Fundamental parameters of galaxies;  Galaxies;  Galaxy formation;  Galaxy structure;  Haloes

Publisher

Blackwell

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2007.11899.x

Copyright

Copyright © 2007 Royal Astronomical Society. The accepted manuscript of this paper is reproduced here in accordance with the copyright policy of the publisher. The definitive publication is available at www.interscience.wiley.com.

Full text

Peer reviewed