Near-infrared images of star forming regions containing masers^*,**

Las Campanas observations of 31 southern sources

¹ Division of Physics, Mathematics and Astronomy, California Institute of Technology, MS105-24, Pasadena, CA 91125, U.S.A.
² Dipartimento di Astronomia e Scienza dello Spazio, Università degli Studi di Firenze, Largo E. Fermi 5, I-50125 Firenze, Italy
³ Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy
⁴ Istituto di Astrofisica Spaziale, C.N.R., C.P. 67, I-00044 Frascati, Italy
⁵ Las Campanas Observatory, Casilla 601, La Serena, Chile

Send offprint request to: Testi: Caltech, lt@astro.caltech.edu

Received: 17 July 1997
Accepted: 24 October 1997

Abstract

We present sensitive high resolution near infrared (NIR) broad band (J, H, and K) observations of a sample of 31 Star Forming Regions (SFRs) which contain H₂O and OH maser sources. The observations are aimed at the detection and characterization of Young Stellar Objects (YSOs) which may be the source of excitation of the maser emission. In spite of the large number of sources detected in the regions, using positional coincidence and NIR colours we are able to reliably identify K-band sources related to the masing gas in a large fraction of the observed regions. The NIR infrared sources selected from close positional coincidence with the maser show strong NIR excesses and most probably represent the YSOs still embedded in their parental cocoon where the maser emission occurs.