Daily Image
01-03-2024
Milliarcsecond Localisation of the Hyperactive Repeating FRB 20220912A
| Submitter: | Danté Hewitt, Shivani Bhandari, Benito Marcote, Jason Hessels et al. |
| Description: | FRB 20220912A is one of the most active fast radio burst (FRB) sources known to date. During the peak of its activity, it accounted for a few percent of the entire all-sky rate of FRBs above a fluence threshold of 100 Jy ms! Thanks to this, it has been the focus of numerous follow-up campaigns. In a recent MNRAS paper by Hewitt et al., we used the European VLBI Network (EVN) to detect 150 bursts from this hyperactive source, allowing us to localise it to a precision of a few milliarcseconds - hundreds of times more precise than the previous localisation precision. These efforts are part of our ongoing EVN-Lite project, PRECISE, which aims to localise repeating FRB sources to the highest-possible precision. We showed that FRB 20220912A resides closer to (yet still offset from) the center of its host galaxy, which was earlier identified using a localisation from the Deep Synoptic Array 110 (DSA-110). The background in the images above is a deep R-band optical image taken with Keck II/ESI (kindly shared with us by Vikram Ravi). The 90% error ellipse of the DSA-110 localization is overplotted in white, and the contours of a catalogued Apertif (APTF) radio continuum source in grey. Our EVN position is shown by the cyan cross, which falls just outside the DSA-110 localisation ellipse. We found no compact persistent radio continuum source in our EVN observations, meaning that the APTF emission is likely due to star-formation in the host galaxy as opposed to a compact nebula powered by the FRB source. Milliarcsecond localisations such as these will be particularly useful in the coming era where optical telescopes such as the Extremely Large Telescope will be able to match the angular resolution, allowing us to zoom-in on the local environments of FRB sources at the (sub-)parsec level. Imagine finding stellar counterparts to FRB sources by resolving the population of massive stars in the host galaxies! |
| Copyright: | Hewitt |
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