The truncation of the stellar disc of NGC 6504

Free access article

Issue		A&A Volume 472, Number 2, September III 2007


Page(s)		L39 - L42
Section		Letters
DOI		http://dx.doi.org/10.1051/0004-6361:20078214

A&A 472, L39-L42 (2007)
DOI: 10.1051/0004-6361:20078214

Letter

The truncation of the stellar disc of NGC 6504

E. Florido^{1, 2}, E. Battaner^{1, 2}, A. Zurita^{1, 2}, and A. Guijarro^{1, 3, 2}

¹ Departamento de Física Teórica y del Cosmos, Universidad de Granada, Spain
e-mail: estrella@ugr.es
² Instituto Carlos I. Física Teórica y Computacional, Universidad de Granada, Spain
³ Centro Astronómico Hispano Alemán, Almería, Spain

(Received 4 July 2007 / Accepted 19 July 2007)

Abstract
Context.This is the first work reporting observations of the truncation of a stellar disc, in both the optical and the NIR spectral ranges. No galaxy has been observed at both wavelengths with the required depth. The optical radial profiles of spiral galaxy discs seem to suggest a double exponential behaviour, whilst NIR profiles seem to show a real truncation.
Aims.We study one galaxy with the best available resolution and detail, in both optical and NIR bands, with the same deprojection method and similar reduction procedures, to see if the different descriptions are real.
Methods.Optical observations (V band) were made with the William Herschel Telescope. NIR observations (J, H, $K_{\rm s}$ ) were made with the CAIN infrared camera on the Carlos Sánchez Telescope in Tenerife (Spain). The deprojection method was that described in Florido et al. (2001, A&A, 378, 82; 2006a, A&A, 455, 467).
Results.NGC 6504 has a real truncation in both the optical and the NIR radial profiles. A double exponential does not fit the observed optical profile. The truncation radius is larger in the V band than in the NIR by ~10 arcsec, about 3 kpc (equivalent to about 10%). We examine the constraints of this observation in theoretical scenarios.

Key words: galaxies: fundamental parameters -- galaxies: photometry -- galaxies: structure

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.