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4th of October 2023
ASKAP Variable Sources on Minute Timescales
by Wang et al.
Wang et al. present results from a radio survey for variable and transient sources on 15-min timescales, using ASKAP pilot survey data. The variability search was conducted within each 8–10 hour pilot survey observation on a 15-min timescale. In total, 38 variable and transient sources were detected: seven are known pulsars, and another eight sources are stars, only one of which had previously identified as a radio star. For the remaining 23 objects, 22 are associated with active galactic nuclei or galaxies, and their variations are caused by discrete, local plasma screens. The remaining source has no multi-wavelength counterparts and is therefore yet to be identified. This is the first large-scale radio survey for variables and transient sources on minute timescales at a sub-mJy sensitivity level. The team expect to discover ∼1 highly variable source per day using the same technique on the full ASKAP surveys. The figures above show the radio flux density (in mJy per beam) for one of the radio stars, CD-28 302, which was identified as a non-single star by Gaia with an orbital period of ∼147.0 days. CD-28 302 had not previously been identified as a radio star. The measured Gaia parallax yields a distance of 11.8 parsecs (38 light years).

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