About the morphology of dwarf spheroidal galaxies and their dark matter content

¹ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
² Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
³ Sterrewacht Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands

Corresponding author: C. J. Walcher, walcher@mpia.de

Received: 18 July 2002
Accepted: 20 May 2003

Abstract

The morphological properties of the Carina, Sculptor and Fornax dwarfs are investigated using new wide field data with a total area of 29 square degrees. The stellar density maps are derived, hinting that Sculptor possesses tidal tails indicating interaction with the Milky Way. Contrary to previous studies we cannot find any sign of breaks in the density profiles for the Carina and Fornax dwarfs. The possible existence of tidal tails in Sculptor and of King limiting radii in Fornax and Carina are used to derive global ratios, without using kinematic data. By matching those ratios to kinematically derived values we are able to constrain the orbital parameters of the three dwarfs. Fornax cannot have smaller than 3 and must be close to its perigalacticon now. The other extreme is Sculptor that needs to be on an orbit with an eccentricity bigger than 0.5 to be able to form tidal tails despite its kinematic .