86 GHz SiO maser survey of late-type stars in the inner Galaxy ^*,**

II. Infrared photometry of the SiO target stars

¹ Leiden Observatory, PO Box 9513, 2300 RA Leiden, The Netherlands e-mail: messineo@strw.leidenuniv.nl; habing@strw.leidenuniv.nl
² Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: menten@mpifr-bonn.mpg.de
³ Institut d'Astrophysique de Paris, CNRS & Université Paris 6, 98bis Bd Arago, 75014 Paris, France e-mail: omont@iap.fr
⁴ National Radio Astronomy Observatory, PO Box 0, Socorro NM 87801, USA e-mail: lsjouwerman@aoc.nrao.edu

Corresponding author: M. Messineo, messineo@strw.leidenuniv.nl

Received: 9 October 2003
Accepted: 19 December 2003

Abstract

We present a compilation and study of DENIS, 2MASS, ISOGAL, MSX and IRAS 1–25 μm photometry for a sample of 441 late-type stars in the inner Galaxy, which we previously searched for 86 GHz SiO maser emission [CITE]. The comparison of the DENIS and 2MASS J and K_S magnitudes shows that most of the SiO targets are indeed variable stars. The MSX colours and the IRAS  colour of our SiO targets are consistent with those of Mira type stars with dust silicate feature at 9.7 μm feature in emission, indicating only a moderate mass-loss rate.