Catalogue of Infrared Images of OH/IR stars


These pages are still in preparation.

Acknowledgements: Thanks to J.P. Krumme for running DUSTY to create the model spectral energy distributions and S. Tippenhauer for preparation of most of the 2MASS finding charts. A. Berkner prepared the GLIMPSE finding charts and extracted flux densities from the GLIMPSE source lists (Version: 04/15/2005). The 2MASS images were taken from the 2MASS All-Sky Survey Data server. The GLIMPSE images were taken from the GLIMPSE Image Atlas-Version 1.0 in July 2006.

Description: The current list of OH/IR stars was taken from the compilation of Baud et al. 1981. It contains N=114 objects with double-peaked 1612 MHz OH maser profiles selected from three surveys along the galactic plane carried out end of the seventies. They were found at galactic longitudes 10 < l < 150 and galactic latitudes |b| < 4. Typical limiting sensitivities were around 1 Jansky. I added the OH/IR star OH 19.2-1.0, which was omitted by Baud et al. because of its peculiar maser profile having three peaks. OH 57.5+1.8 was found by Engels (1997) to be a blend of two OH masers and is counted here as two objects OH 57.5+1.8A and B. The final list contains therefore N=116 stars.

In many cases the radio coordinates of the OH/IR stars have large uncertainties (up to arcminutes) inhibiting its identification in the near-infrared, for example with the 2MASS and DENIS surveys. It was therefore necessary to search for the most accurate coordinates from a variety of sources beforehand. Follow-up observations of the OH/IR stars listed here are inhomogeneous comprising sources with hundreds of references like the prototype OH/IR star OH 26.5+0.5 and sources like OH 20.4+1.4, which were never reobserved.

The input list of "radio coordinates" (hereafter radio input list ) used to search for infrared counterparts was created in the following way:

Search for IRAS counterparts

IRAS counterparts were searched for in the IRAS Point-Source Catalog, within five arcminutes of the coordinates given in the radio input list. The result was: It should be noted that for several OH/IR stars IRAS counterparts are listed in the literature, for example in the catalogue of stellar 1612 MHz maser sources of Te Lintel-Hekkert (1989). The associations were however never proven despite uncertainties in the radio coordinates of several arc minutes.

Search for MSX counterparts

Searching for counterparts in the mid-infrared point source catalog MSX PSC V2.3 from the Midcourse Space Experiment (MSX) was done using either the radio input list or the coordinates of the IRAS counterpart, whichever coordinate was more accurate. The N=8 questionable IRAS counterparts were searched at the original radio positions and the IRAS positions. All OH masers positions were covered by the MSX survey. The search radius was 1 arcmin. Plausible MSX counterparts were found for all OH/IR stars, except three. These N=113 OH maser sources are For 6 out of 8 OH masers with questionable IRAS counterparts the MSX counterparts were found at the IRAS position and not at the original radio position. This confirms the IRAS counterparts. For OH 23.8+0.2 the MSX counterpart was found at the radio input position and the IRAS counterpart was discarded. No MSX counterpart was found at the radio position of OH 39.6+0.9. The questionable IRAS counterpart to OH 39.6+0.9 is IRAS 18584+0616, which is 259" away from the radio position of Johansson et al. (1977). The spectral energy distribution for IRAS 18584+0616 constructed with data from 2MASS, GLIMPSE and MSX is rather blue and unlike the typical SEDs of OH/IR stars.

The two sources OH 18.3+0.1 and OH 42.8-1.0 remain without IRAS and MSX counterpart within 5 arc minutes of their radio positions.

Search for 2MASS counterparts

Near infrared counterparts were searched for in the Two Micron All Sky Survey using the All-Sky Point Source Catalog and the Atlas images. The maximum search radius was 5 arcsec around the MSX position for the N=113 sources with MSX counterpart.

Comments on individual sources: