CHIME/FRB discovery of a new repeating fast radio burst source FRB 20240114A

ATel #16420; Kaitlyn Shin (MIT) for the CHIME/FRB Collaboration
on 26 Jan 2024; 18:13 UT
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Credential Certification: Kaitlyn Shin (kshin@mit.edu)

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The CHIME/FRB Collaboration reports the discovery of a new repeating source of FRBs (FRB 20240114A). We detected one burst (real-time S/N ~8), and then after a week, observed two more bright bursts (real-time S/Ns 18 and 32) within four days of each other. Both bright detections were streamed through our VOEvents service. This source is especially interesting because it is at a declination ~4.4 degrees where CHIME's daily exposure (FWHM of the beams at 600 MHz) has a median of about 4 minutes (compared to a "typical" daily exposure of ~15 minutes near zenith, e.g., Fig. 5 in CHIME/FRB Collaboration ApJS 257 59), hinting at a high burst rate of the source above ~1 Jy ms fluence thresholds.

From the real-time detection system, the events occurred at 2024-01-14 21:50:39, 2024-01-21 21:30:40, and 2024-01-24 21:20:11 UTC at 400 MHz (topocentric at CHIME near Penticton, Canada). Based on voltage data of the brightest burst, we obtain a brute-force DM of 527.7 pc cm^-3 (consistent with the other bursts, assuming a DM constant of 2.41 x 10^-4 MHz^-2 pc cm^-3 s^-1). The best-fit localization was performed on the voltage data of the two bright events, giving an inverse-variance weighted best position RA (J2000): 321.9162 +- 0.0087 deg, Dec (J2000): 4.3501 +- 0.0124 deg, with errors quoted at 1-sigma uncertainty (Michilli et al. 2021 ApJ, 910, 147).

A preliminary analysis of the voltage data shows that both bright bursts have a Faraday rotation measure consistent with |RM| ~325 rad/m^2 (there is a sign ambiguity because of cable delay effects; Mckinven et al. 2021 ApJ, 920, 138). We also obtain preliminary fluences for the two brightest bursts, averaged over the entire 400-800 MHz CHIME observing band, as 175 +- 22 Jy ms and 919 +- 97 Jy ms (1-sigma uncertainty) for bursts FRB 20240121A and FRB 20240124A, respectively (CHIME/FRB Collaboration arXiv:2311.00111).

Given the large fluences of the bursts and the high estimated burst rate, we encourage rapid multi-wavelength follow-up, especially radio interferometric observations, to further localize FRB 20240114A.

Dynamic spectra of baseband bursts from FRB 20240114A