A pilot study of the radio-continuum emission from MASH planetary nebulae

TL;DR

This study presents radio-continuum observations of 26 planetary nebulae from the MASH catalogue, revealing low surface brightness and old age, and highlights the need for deeper surveys to improve detection rates and parameter accuracy.

Contribution

First radio-continuum survey of MASH planetary nebulae, providing detection statistics, physical parameters, and insights into their evolutionary status.

Findings

11 PNe detected with low surface brightness

Detected nebulae are large and highly diluted, indicating old age

Detection rate is lower compared to non-MASH samples

Abstract

We report an Australia Telescope Compact Array (ATCA) radio-continuum observations of 26 planetary nebulae (PNe) at wavelengths of 3 and 6 cm. This sample of 26 PNe were taken from the Macquarie/AAO/Strasbourg Halpha PNe (MASH) catalogue and previous lists. We investigate radio detection quality including measured and derived parameters for all detected or marginally detected PNe from this combined sample. Some 11 objects from the observed sample have been successfully detected and parametrized. Except for one, all detected PNe have very low radio surface brightnesses. We use a statistical distance scale method to calculate distances and ionised masses of the detected objects. Nebulae from this sample are found to be large (>0.2 pc in diameter) and highly diluted which indicates old age. For 21 PNe from this sample we list integrated Halpha fluxes and interstellar extinction coefficients, either taken from the literature or derived here from the Balmer decrement and radio to Halpha ratio methods. Finally, our detected fraction of the MASH pilot sample is relatively low compared to the non-MASH sub-sample. We conclude that future radio surveys of the MASH sample must involve deeper observations with better uv coverage in order to increase the fraction of detected objects and improve the quality of the derived parameters.