22 GHz Observations with the Resurfaced Central 17 m of the Parkes Radio Telescope

Abstract

At the centre of the Parkes 64—m radio telescope a region of diameter 17 m has recently been resurfaced to improve its efficiency at high frequencies. The first measurements using this section have been made at 22 GHz, in observations of both continuum sources and water tfapour masers. For these observations the receiver front-end used a mixer cooled in liquid nitrogen, followed by a 5 GHz cryogenic parametric amplifier as a second stage. The option of switching against an offset horn was available and the total system noise temperature was ∽ 750 K.

Weak OH Masers in the Direction of H20 Masers

“…The velocity is -18.0 km s" 1 and the position (epoch 1950) was found to be R.A. 17 h 05 m 58 s , Dec. -41°32'50"; the accuracy of the position is limited by the weakness of the emission and the problem of assessing the underlying baseline in the presence of absorption. It agrees quite well with the 22 GHz continuum measurement of the HII region position, at R.A. 17 h 06 m 01 s .2, Dec. -41°32'l6" (Caswell et al 1976).…”

Accurate OH Maser Positions from the SPLASH Survey. III. The Final 96 deg2

“…This star formation site is a well-known HII region. Several papers reported water maser detections toward this site, e.g., Caswell et al (1976) and Batchelor et al (1980). A 6.7 GHz methanol maser has also been detected toward this maser site (Caswell et al 2010).…”

Observations of NH3 in Southern Sources

“…We report here the results of a preliminary southern hemisphere investigation of ammonia in the direction of HII regions using the inner 17-m surface of the Parkes telescope, which has recently been provided with a precision surface (Yabsley 1977). The telescope parameters (beamwidth =2'.9 arc, beam efficiency ^50%) and pointing corrections we have used are from Caswell et al (1976).…”