Detection of 51 bursts from the active repeater FRB 20240114A with micro-structure by the uGMRT

ATel #16494; Ujjwal Panda (NCRA-TIFR), Siddhartha Bhattacharyya (NCRA-TIFR), Chahat Dudeja (NCRA-TIFR), Sanjay Kudale (NCRA-TIFR) and Jayanta Roy (NCRA-TIFR)
on 29 Feb 2024; 18:29 UT
Credential Certification: Jayanta Roy (jroy@ncra.tifr.res.in)

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We report the detection of 51 bursts from the repeating FRB 20240114A, observed using the uGMRT’s Band 4 (550 to 750 MHz) receivers on 25th February 2024 between 03:11:22 and 10:49:24 UTC above 10-sigma significance. We followed up on this FRB after its detection was reported by the CHIME/FRB Collaboration (ATel #16420), and its subsequent localisation by MeerKAT (ATel #16446). We observed the FRB using a phased array (PA) beam of the uGMRT formed towards the position given in ATel #16446. This study follows the detection of 10 bursts with the uGMRT reported in ATel #16452 prior to the localisation. The 51 bursts reported in this ATel have fluences ranging from 0.6 to 27.8 Jy ms, dispersion measures (DMs) ranging from 527.1 to 530.3 pc cm^-3, and intrinsic widths ranging from 0.7 to 12.3 ms, illustrating a highly variable burst morphology for this repeater. The burst rate observed at the GMRT is about 8 per hour above a fluence of 0.6 Jy ms. Some of the bursts are significantly scattered with a time scale of up to 4.7 ms. We also report the detection of rich temporal structure from FRB 20240114A, using coherently dedispersed data at 40.96 micro-seconds, which probed sub-burst time scale up to 100s of micro-second (see Dynamic spectra of two bright bursts). Band-limited emissions of 55 MHz (median value) are seen from this repeater. We would like to thank the Director and the operations group of the observatory for the prompt time allocation and scheduling of our observation. The GMRT is run by the National Centre for Radio Astrophysics, of the Tata Institute of Fundamental Research.

Dynamic spectra of two bright bursts