Letter to the Editor

The infrared L'-band view of the Galactic Center with NAOS-CONICA at VLT^*

¹ Observatoire de Paris, LESIA, 5 place Jules Janssen, 92195 Paris Cedex, France e-mail: {yann.clenet; daniel.rouan; eric.gendron; francois.lacombe}@obspm.fr
² Observatoire de Grenoble, LAOG, BP 53, 38041 Grenoble Cedex 09, France e-mail: anne-marie.lagrange@obs.ujf-grenoble.fr
³ Office National d'Etudes et de Recherches Aérospatiales (ONERA), DOTA, BP 72, 92322 Châtillon Cedex, France e-mail: rousset@onera.fr
⁴ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, 85748 Garching, Germany e-mail: {genzel; rainer}@mpe.mpg.de
⁵ I. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937 Köln, Germany e-mail: eckart@ph1.uni-koeln.de
⁶ European Southern Observatory (ESO), Alonso de Córdova, Casilla 3107, Vitacura, Casilla 19001, Santiago 19, Chile e-mail: omarco@eso.org
⁷ European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany e-mail: ltacconi@eso.org

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

Received: 16 April 2003
Accepted: 14 November 2003

Abstract

We report on Galactic Center L'-band observations made during NAOS/CONICA Science Verification. Colors of the inner 2´´ stars reveal an infrared excess of S2, the closest star to the black hole, that could sign the first thermal infrared detection of Sgr A*. A multi-wavelength maximum likelihood analysis has allowed us to eliminate all but two of the candidates for gravitational lensing proposed by [CITE]. Our observations of the thin and intersecting structures of the Northern Arm could trace several shocks heating the neighbooring dust rather than a stream of matter in orbit around the central mass as previously thought.