86 GHz SiO maser survey of late-type stars in the Inner Galaxy

Abstract

Abstract. We present 86 GHz (v = 1, J = 2 → 1) SiO maser line observations with the IRAM 30-m telescope of a sample of 441 late-type stars in the Inner Galaxy (−4 • < l < +30 • ). These stars were selected on the basis of their infrared magnitudes and colours from the ISOGAL and MSX catalogues. SiO maser emission was detected in 271 sources, and their line-of-sight velocities indicate that the stars are located in the Inner Galaxy. These new detections double the number of line-of-sight velocities available from previous SiO and OH maser observations in the area covered by our survey and are, together with other samples of e.g. OH/IR stars, useful for kinematic studies of the central parts of the Galaxy.

Near- and mid-infrared colors of evolved stars in the Galactic plane. TheQ1 andQ2 parameters

“…Alard et al (2001), large amplitude variables (LAVs) stars from Glass et al (2001), and AGBs with SiO maser emission from Messineo et al (2002). OH/IR stars are from Sevenster (2002).…”

“…The sample of SiO masing stars of Messineo et al (2002) consists of 271 stars, which were color selected from the DENIS, ISOGAL, 2MASS and MSX catalogs. Information on variability and photometric properties suggests that the whole sample consists of Mira-like stars .…”

“…While this is a sample of mostly AGB stars, it may likely include a few RSGs . Positions have an accuracy of 1 Along the text we will consider as an SiO maser sample the SiO masing stars by Messineo et al (2002) plus the 77 masing LAVs by Glass et al (2001); Imai et al (2002), while we will refer to the remaining LAVs by Glass et al (2001) The different numbers of matches found in the GLIMPSE and MSX catalogs are due to differences in their sensitivity and sky coverage. While MSX covers the whole Galactic plane to ±5 • of latitude, the GLIMPSE survey is confined to a narrow latitude range ±1 • .…”

“…AGBs which are older and dynamically relaxed, may serve as direct tracers of the Galactic gravitational potential (Habing et al 2006). Kinematics of AGBs have been successfully used to map mass components devoid of gas (e.g., galactic bars, Habing et al 2006;Messineo et al 2002).…”

“…Several thousands of AGBs have been detected via their maser emission, or photometric pulsation properties (e.g. Habing et al 2006;Alard et al 2001;Glass et al 2001;Deguchi et al 2004;Messineo et al 2002;Sevenster 2002, and references therein). These numbers are too small for quantitatively constraining theories of Galactic formation and evolution (e.g.…”