Abstract. We present observations of the region between | | ≤ 10• and |b| ≤ 3• in the OH 1612.231 MHz line, taken in 1993 October and November with the Australia Telescope Compact Array 1 . The region was systematically searched for OH/IR stars and was covered completely with 539 pointing centres separated by 30 . The size of the dataset calls for a special reduction technique that is fast, reliable and minimizes the output (positions and velocities of possible stars only). Having developed such a reduction method we found 307 OH masing objects, 145 of which are new detections. Out of these, 248 have a standard double-peaked spectral profile, 55 a single-peaked profile and 4 have nonstandard or irregular profiles. In this article we analyse the data statistically and give classifications and identifications with known sources where possible. The astrophysical, kinematical, morphological and dynamical properties of subsets of the data will be addressed in future articles. These observations are part of a larger survey, covering | | ≤ 45• and |b| ≤ 3 • , with the Australia Telescope Compact Array and the Very Large Array.The electronic version of this paper, that includes table and spectra, can be obtainded from http://www.edphys.fr. The table is also available via anonymous ftp (130.79.128.5) or through the World Wide Web (http://cdsweb.u-strasbg.fr/Abstract.html).

Abstract. We present observations of the region between 5• ≤ ≤ 45• and |b| ≤ 3• , in the OH 1612.231 MHz line, taken from 1993 to 1995 with NRAO's Very Large Array (VLA). These observations are the last part of a larger survey, covering | | ≤ 45• and |b| ≤ 3 • , with the Australia Telescope Compact Array (ATCA) and the VLA. The region was systematically observed on a 30 × 30 grid in ( , b) and the resulting coverage was 92%, with 965 pointings. We found 286 OH-masing objects, 161 of which are new detections and 207 have reliable IRAS pointsource identifications. The outflow velocity was determined for 276 sources. A total of 766 sources were detected in the combined ATCA/VLA survey, of which 29 were detected in two regions of the survey. In this article we analyse the data statistically and give identifications with known sources where possible. The "efficiency" of this VLA survey is 75% of that of the ATCA Bulge survey. This efficiency was determined by comparing the detections in the region where the two surveys overlap. The completeness-and error characteristics are similar, though less homogeneous, except for the much larger errors in the flux densities. The relatively large surface number density found in the northern disk, suggests that we can see the Bar extending to higher longitudes on this side of the galactic Centre.

We present the results of 22 GHz H 2 O maser observations of a sample of 85 postYasymptotic giant branch ( post-AGB) candidate stars, selected on the basis of their OH 1612 MHz maser and far-infrared properties. All sources were observed with the Tidbinbilla 70 m radio telescope, and 21 detections were made; 86 GHz SiO Mopra observations of a subset of the sample are also presented. Of the 21 H 2 O detections, 15 are from sources that are likely to be massive AGB stars and most of these show typical, regular H 2 O maser profiles. In contrast, nearly all the detections of more evolved stars exhibited high-velocity H 2 O maser emission. Of the five sources seen, v223 (W43A, IRAS 18450À0148) is a well-known ''water-fountain'' source that belongs to a small group of post-AGB stars with highly collimated, high-velocity H 2 O maser emission. A second source in our sample, v270 (IRAS 18596+0315), is also known to have high-velocity emission. We report the discovery of similar emission from a further three sources, d46 (IRAS 15445À5449), d62 (IRAS 15544À5332), and b292 (IRAS 18043À2116). The source d46 is an evolved post-AGB star with highly unusual maser properties. The H 2 O maser emission from d62 is probably associated with a massive star. The source b292 is a young post-AGB star that is highly likely to be a water-fountain source, with masers detected over a velocity range of 210 km s À1 .

Abstract. We present observations of the region between −45• ≤ ≤ −10• and |b| ≤ 3 • in the OH 1612.231 MHz line, taken in 1994 January with the Australia Telescope Compact Array (ATCA)1 . These observations are part of a larger survey, covering | | ≤ 45• and |b| ≤ 3 • , with the ATCA and the Very Large Array. In a previous article we have discussed the observational strategy in detail. In this paper we present only the objects found in this part of the survey. The region was systematically searched for OH-maser emission and was covered completely with 910 pointing centres separated by 30 . We found 202 OHmasing objects, 112 of which are new detections. Out of the 202 objects, 166 have a standard double-peaked spectral profile, 32 a single-peaked profile and 4 objects have non-standard or irregular profiles. In this article we analyse the data statistically and give classifications and identifications with known sources where possible. The astrophysical, kinematical, morphological and dynamical properties of subsets of the data will be addressed in future articles 2 .

We determine the values of parameters of an N-body model for the Galaxy developed by Fux via comparison with an unbiased, homogeneous sample of OH/IR stars. Via Monte-Carlo simulation, we find the plausibilities of the best-fitting models, as well as their errors. The parameters that are constrained best by these projected data are the total mass of the model and the viewing angle of the central Bar, although the distribution of the latter has multiple maxima. The best model has a viewing angle of 44 degrees, semi-major axis of 2.5 kpc, a bar mass of 1.7E10 solar masses and a tangential velocity of the local standard of rest of 171 km/s . We argue that the lower values that are commonly found from stellar data for the viewing angle (around 25 degrees) arise when too few coordinates are available, when the longitude range is too narrow or when low latitudes are excluded from the fit. The new constraints on the viewing angle of the galactic Bar from stellar line-of-sight velocities decrease further the ability of the Bar's distribution to account for the observed micro-lensing optical depth toward Baade's window : our model reproduces only half the observed value. The signal of triaxiality diminishes quickly with increasing latitude, fading within approximately one scaleheight. This suggests that Baade's window is not a very appropriate region to sample Bar properties.Comment: 10 pages, 8 figures, TeX, accepted for publication in MNRA