FRB 20250316A is an exceptionally bright fast radio burst (FRB) discovered and localised by CHIME/FRB and its Outriggers to a nearby host galaxy, NGC 4141, at ~40 Mpc (ATel #17081, #17086, #17114).

We observed FRB 20250316A at high cadence as part of the HyperFlash project, which monitors known (repeating) FRB sources using a network of 25- to 32-meter European radio telescopes. Observations are carried out on a best-effort basis and, whenever possible, the telescopes observe simultaneously at complementary wavelengths. During this campaign, we observed using telescopes at Westerbork (Netherlands), Dwingeloo (Netherlands), Stockert (Germany), Torun (Poland), and Onsala (Sweden). We previously described our observing strategy in ATel #16565 and Kirsten et al. 2024.

Between 16 March (MJD 60750) and 26 March 2025 (MJD 60760), we accumulated a total of 170 hours of exposure across all five telescopes. Accounting for simultaneous observations, this corresponds to 120 hours at L-band (1.4 GHz) and 20 hours at P-band (0.33 GHz). We detected no bursts above our completeness thresholds of 15 Jy ms (L-band) and 70 Jy ms (P-band), which corresponds to an emitted energy of ~10³⁶ erg assuming a burst bandwidth of 100 MHz.

The absence of subsequent bursts, combined with the source's exceptional proximity, suggests that FRB 20250316A is unlikely to be a hyperactive repeater. Instead, it may emit bursts at a much lower repetition rate or lower energies. Alternatively, this source could be a non-repeating FRB.

Ould-Boukattine et al. 2025, The Astronomer's Telegram, No. 17124.