Northern Cross detection of FRB 20251229A at 408 MHz

ATel #17671; A. Geminardi (IUSS Pavia), D. Pelliciari (INAF-IRA), P. Esposito (IUSS Pavia), G. Bernardi (INAF-IRA), M. Pilia (INAF-OAC), G. Naldi (INAF-IRA) on behalf of a larger collaboration
on 11 Feb 2026; 21:03 UT
Credential Certification: Paolo Esposito (paoloesp@iasf-milano.inaf.it)

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We report the detection of FRB 20251229A with the Northern Cross radio telescope at 408 MHz.

Following the discovery of FRB 20251229A by the CHIME/FRB Collaboration (ATel #17574) and the detections by FAST (ATel #17591), the Northern Cross FRB collaboration is undergoing a follow-up campaign on this active repeating FRB. The monitoring started on 2026-01-29, collecting (so far) a total on-source time of 4.6 hours, with daily observing windows of ∼ 25 minutes. Observations were carried out with a 14.8 MHz bandwidth at a central frequency of 408 MHz, with a 14.468 kHz channel width and a 138.24 μs sampling time. The FRB search was performed using Heimdall (Barsdell et al. 2012) and FETCH (Agarwal et al. 2020) spanning a DM range between 160 and 230 pc cm⁻³ considering only signals with SNR > 7.

The topocentric time of arrival of the burst is 2026-02-07 10:47:01.845 UTC at 400 MHz at Medicina (BO, Italy). The dispersion measure that maximizes the signal-to-noise ratio is 194 ± 2 pc cm⁻³, consistent with previously reported detections (ATel #17574 and #17591). The signal shows multiple substructures, with four clear peaks, and from our best-fit analysis we obtained a total fluence of ∼ 100 Jy ms and a duration of 7.72 ± 0.28 ms.

We will continue the monitoring over the next weeks. The link below provides the waterfall plot for this burst.

https://drive.google.com/drive/folders/1ivPLN50zbCcTW-z15ZjtF2wjPNwz4iKs?usp=sharing