Support ATel At Patreon

[ Previous | Next | ADS ]

Discovery of a radio continuum counterpart spatially associated with the repeating FRB 20240114A

ATel #16695; Xian Zhang, Wenfei Yu (Shanghai Astronomical Observatory)
on 8 Jul 2024; 15:30 UT
Credential Certification: Wenfei Yu (wenfei@shao.ac.cn)

Subjects: Radio, Fast Radio Burst

Referred to by ATel #: 16820, 16864, 16885

FRB 20240114A is a repeating FRB discovered by the CHIME/FRB Collaboration (ATel #16420) in January 2024. Follow-up radio observations with multiple telescopes have revealed its hyperactive bursting nature with bursts detected in the frequency range from a few hundreds of MHz up to 6 GHz (e.g., ATel #16432, ATel #16452, ATel #16505, ATel #16597, ATel #16620). Based on the precise localisation of FRB 20240114A achieved with MeerKAT (ATel #16446) and EVN (ATel #16542) observations, its likely host galaxy J212739.84+041945.8 at a redshift of z=0.13 (ATel #16613) (at a luminosity distance of ~610 Mpc) was confidently measured. Efforts on searching for its X-ray (ATel #16645) and radio continuum counterparts (ATel #16452; Panda et al. 2024, arXiv:2405.09749; Kumar et al. 2024, arXiv:2406.12804) were conducted, but only upper limits were reported as of yet. Surprisingly, enhanced gamma-ray activities and a GeV gamma-ray flare coincident with the direction of the FRB (ATel #16594, ATel #16630) were identified in Fermi-LAT data.

During the active bursting phase soon after the discovery of FRB 20240114A, two bursts were detected and reported at L-band (ATel #16446) from the MeerKAT DDT observation performed on February 9, 2024, by MeerTrap team. We analyzed the public data with visibilities of 2s integration time of the observation (see (ATel #16446) for details), and found a radio continuum counterpart with a source position of (R.A., Dec.) [J2000] = (21h27m39.82s, 4d19m47.106s) with 1 sigma statistical uncertainty of (0.65 arcsec, 0.89 arcsec), which is spatially coincident with the FRB positions given by MeerKAT (looks slightly offset from that reported from EVN (ATel #16542), in which the position might have been distorted by sidelobe structure). The measured flux density is 72 +/- 14 microJy (spectral luminosity of L_1.3GHz=3.2*10^{28} erg s^{-1} Hz^{-1} at the luminosity distance of 610 Mpc) with an in-band spectrum index of -1.1 +/- 0.8 using source detections of 92 +/- 17 microJy at 1.07 GHz and 64 +/- 14 microJy at 1.50 GHz.

Therefore, the radio continuum source is very likely the persistent radio source (PRS) of the FRB, thus the FRB is similar to other PRS-FRB associations, or at least a Transient Radio Source (TRS) in association with the FRB that has not been seen before. This mysterious, luminous radio source therefore potentially enlarge the sample of FRB-PRS association or alternatively provide potential new clues to the evolution of FRBs.

We would like to thank the staff at the South African Radio Astronomy Observatory (SARAO) and the MeerTrap team for making the observations and data publicly available.