Letter to the Editor

Stellar dynamics of blue compact galaxies ^*

I. Decoupled star–gas kinematics in ESO 400-G43

¹ Stockholm Observatory, AlbaNova University Center, 10691 Stockholm, Sweden
² Observatoire Astronomique Marseille-Provence & Laboratoire d'Astrophysique de Marseille, 2 place Le Verrier, 13248 Marseille Cedex 4, France
³ Uppsala Astronomical Observatory, Box 515, 75120 Uppsala, Sweden
⁴ Institute d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
⁵ Instituto Astrofisica de Andalucia (CSIC), Camino Bajo de Huetor 24, 18008 Granada, Spain

Corresponding author: G. Östlin, ostlin@astro.su.se

Received: 12 March 2004
Accepted: 10 April 2004

Abstract

In this letter we present the first results from a program aimed at measuring the stellar kinematics of blue compact galaxies by observing the near-infrared Calcium triplet. We show the first results for ESO 400-G43 based on deep VLT/FORS2 spectroscopy. The instabilities found in the central gaseous velocity field are not seen in the solid body stellar rotation curve, indicating that stars and gas are kinematically decoupled in this galaxy. Even if this galaxy has a perturbed gaseous velocity field, the stellar velocity dispersion on average agrees well with that derived from the nebular lines.