SIMBAD references

The maser site OH 323.459-0.079 has been studied using the Long Baseline Array of the Australia Telescope National Facility. Simultaneous observations of the 1665- and 1667-MHz hydroxyl ground-state transitions yielded a series of maps at a velocity spacing of 0.18km.s^–1, in both senses of circular polarization, with tenth-arcsec spatial resolution. Many small-diameter maser spots were detected within a 2-arcsec region. Pairs of spots with the same position, but with right- and left-hand circular polarization offset in frequency, reveal Zeeman splitting. Six pairs were found, and in four cases, the pairs at 1667 and 1665MHz mutually corroborate the derived values of magnetic field and (central) kinematic velocity. Over the whole site, magnetic field estimates range from +1.47 to +4.13mG with a median value of +2.5mG. The excited state of OH at 6035MHz also displays Zeeman pairs revealing a similar magnetic field, and we show that the most prominent of these pairs coincides with the most prominent pair at 1665 and 1667MHz.

We also compared the morphology and kinematics at 1665 and 1667MHz with those of maser emission from the excited state of OH at 6035MHz and from methanol at 6668MHz. All three varieties of masers appear intermingled, and associated with an ultracompact Hii region. In many respects we find that OH 323.459-0.079 is similar to W3(OH), one of the few other maser sites yet studied in comparable detail.