509 citations · 3.1k across the 33 of their papers we have counts for
7 papers · 1 filter
Revisiting the formaldehyde masers
D. J. van der Walt, L. L. Mfulwane
The 4.8 GHz formaldehyde masers are one of a number of rare types of molecular masers in the Galaxy. The aim of the present calculations is to explore a larger region of parameter…
A note on the periodic methanol masers in G9.62+0.20E
DJ van der Walt, JM Maswanganye, S Etoka +2
A number of mechanisms to understand the periodic class II methanol masers associated with some high-mass star forming regions have been proposed in the past. Two recent proposals,…
Pumping of the 4.8 GHz HCO masers and its implications for the periodic masers in G37.55+0.20
D. J. van der Walt
Periodic or regular flaring of class II methanol masers in nine high mass star forming regions is now a well established phenomenon. Amongst the nine star forming regions, G37.55+0…
A near-infrared study of the star forming region RCW 34
D. J. van der Walt, H. M. de Villiers, R. J. Czanik
We report the results of a near-infrared imaging study of a arcmin region centered on the 6.7 GHz methanol maser associated with the RCW 34 star forming region…
On the methanol masers in G9.62+0.20E and G188.95+0.89
DJ van der Walt
A comparison between the observed light curves of periodic masers in G9.62+0.20E and G188.95+0.89 and the results of a simple colliding-wind binary model is made to establish wheth…
Periodic class II methanol masers in G9.62+0.20E
D. J. van der Walt, S. Goedhart, M. J. Gaylard
We present the light curves of the 6.7 and 12.2 GHz methanol masers in the star forming region G9.62+0.20E for a time span of more than 2600 days. The earlier reported period of 24…
Short-period variability in the Class II methanol maser source G12.89+0.49 (IRAS 18089-1732)
S. Goedhart, M. C. Langa, M. J. Gaylard +1
Time series are presented for the class II methanol maser source G12.89+0.49, which has been monitored for nine years at the Hartebeesthoek Radio Astronomy Observatory. The 12.2 an…