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Nov 21

The search for dwarf stars with large telescope arrays with Kovi Rose

Date & Time
21 November 2023 7:30 PM - 10:00 AM
(UTC+11:00) Australia/Sydney

Radio emission from stars and pulsars is a powerful tool for studying these objects. However, it can be difficult to distinguish these objects from other transient sources, like AGN (Active Galactic Nuclei). Using monthly observations from the Australian SKA Pathfinder (ASKAP) we can identify these AGN and pulsars detected in the repeat observations of the new Variables and Slow Transients (VAST) survey. However, stochastic or rotationally modulated emission from stars may only be detected in a single observation, and appear phenomenologically similar to transient radio sources.

One way to distinguish between stars and pulsars and other transients is to use the property of circular polarisation. Stars and pulsars are the only known sources of significant circularly polarised emission. This means that we can use circular polarisation to remove contaminants in transient searches.

We used the Rapid ASKAP Continuum Survey (RACS) to identify circularly polarised sources. We found 32 pulsars and 65 stars; 51 of which had not been previously detected in radio. One of these stars was a brown dwarf, which was the coolest star ever found to produce radio emission. 

Our method provides a new way to identify radio emission from stars and pulsars in all sky surveys. This method can be used with future all sky radio surveys to identify stars, pulsars, and other variables to separate them out from transient radio events. This will be important for future surveys, such as the Square Kilometre Array (SKA), which will be able to detect millions of new radio sources.

Event Type
General Meeting

Saturday 11th Nov 2023
Beginners Night in the Field (BNF), is OFF, with Bad Weather Belrose
This is a night for beginners to come along and learn how to set up a telescope. ...
Monday 4th Dec 2023
Welcome to New Members (zoom)
An introductory zoom session for new members to NSAS. The aim is to welcome new members so that they understand the societies facilities and meetings and how to get the most out of the club. ...