Astron. Astrophys. 363, 1026-1028 (2000)

2. Observations and reduction

The radio observations were obtained at the Australia Telescope National Facility by one of us (MW) using the Compact Array at Narrabri on 27 July 1994. The objects 1934-638 and 1236-684 were used as primary and secondary calibrators, respectively. WR 46 and WR 50 were observed intermittently together with a secondary calibrator with on-source total integration time of 7:10 hrs and 6:20 hrs for WR 46 and WR 50, respectively. Because of possible detection problems in the center of the field, a 30" offset to the south was applied for the program stars. The radio fluxes were determined at 3 cm (8640 MHz) and 6 cm (4800 MHz), both with a bandwidth of 128 MHz. The reduction was performed with the NEWSTAR -package of the Westerbork Synthesis Radio Telescope.

The field of WR 50 at 6 cm showed a source at and , with a flux of 45 mJy (7´ east of WR 50). At 3 cm this object is outside the map. The source brightness is on the detection limit for the PMN-S catalogue (Wright et al. 1994) and is not mentioned therein. We could use the source to self-calibrate the observation. These phase corrections improved the radio map considerably and were also used for the WR 46 observation.

The center of the field (30" south of WR 46) shows a faint offset problem (0.4 mJy and 0.3 mJy at 3 and 6 cm, respectively). None of the radio maps show a source at the positions of WR 46 nor of WR 50. Table 1 lists the upper limits as three times the noise in the reduced radio maps.

Table 1. The upper limits (3) for the radio flux (mJy) of WR 46 and WR 50 obtained at the Australia Telescope Compact Array (ATNF)

© European Southern Observatory (ESO) 2000

Online publication: December 5, 2000
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