Adaptive optics -band observations of the Galactic Center region

¹ Observatoire de Paris, DESPA, 5 place Jules Janssen, 92190 Meudon, France
² ONERA, 29 avenue de la Division Leclerc, BP 72, 92322 Chatillon Cedex, France
³ Gemini Observatory, 670 N. A'ohoku Place, Hilo, Hawaii, 96720, USA

Corresponding author: Y. Clénet, yann.clenet@obspm.fr

Received: 5 February 2001
Accepted: 20 June 2001

Abstract

L-band adaptive optics observations of the Galactic Center region have been performed in June 1999 and May 2000 at La Silla with the 3.6 m telescope, using the ADONIS adaptive optics system. In June 1999, we used a dedicated infrared wave-front sensor, RASOIR. This paper reports on the photometry and astrometry of more than 40 stars. Thanks to additional adaptive optics K-band observations made at CFHT, colour-magnitude diagrams have been constructed to identify individual sources with various types of stars known in this region (AGB, LPV, WC9, WN9/WN10, Ofpe/WN9, YSO). The so-called "cool slash" stars (Ofpe/WN9) appear to be numerous in the field and an estimation of the extinction coefficient towards the Galactic Center from the colours of these intrinsically weakly absorbed stars leads to A_K=2.7, which is among the lowest published values.