The puzzle about the radial cut-off in galactic disks

Narayan, CA and Jog, CJ (2003) The puzzle about the radial cut-off in galactic disks. In: Astronomy and Astrophysics, 407 (3). L59-L62.

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Abstract

The stellar disk in a spiral galaxy is believed to be truncated physically because the disk surface brightness is observed to fall faster than that for an exponential in the outer, faint regions. We review the literature associated with this phenomenon and find that a number of recent observations contradict the truncation picture. Hence we question the very existence of a physical outer cut-off in stellar disks. We show, in this paper, that the observed drop in the surface brightness profiles in fact corresponds to a negligible decrease in intensity, and that this minor change at the faint end appears to be exaggerated on a log-normal plot. Since minor deviations from a perfect exponential are common throughout the disk, we suggest that such a deviation at the faint end could easily give rise to the observed sharp drop.

Item Type:	Journal Article
Publication:	Astronomy and Astrophysics
Publisher:	EDP Sciences
Additional Information:	Copyright of this article belongs to EDP Sciences.
Keywords:	Galaxies;Fundamental parameters – galaxies;Photometry – galaxies;Spiral – galaxies;Structure – Galaxy;Structure
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	27 Apr 2007
Last Modified:	19 Sep 2010 04:37
URI:	http://eprints.iisc.ac.in/id/eprint/10729

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