Detection of FRB 20251018 by the PuMA Collaboration at the Argentine Institute of Radio Astronomy
ATel #17580; H. Prajapati (RIT), S. B. Araujo Furlan (IATE, FAMAF), E. Zubieta (IAR, UNLP), C. O. Lousto (RIT), G. Gancio (IAR), F. Garcia (IAR, UNLP), S. del Palacio (Chalmers, IAR), on behalf of the PuMA Collaboration
on 7 Jan 2026; 00:25 UT
Credential Certification: Ezequiel Zubieta (ezubieta@iar.unlp.edu.ar)
Subjects: Radio, Fast Radio Burst
The PuMA Collaboration reports the detection of a new Fast Radio Burst (FRB), designated FRB 20251018, using the 30-m radio telescope (Antenna A2) at the Argentine Institute of Radio Astronomy (IAR). This detection is part of an ongoing high-cadence FRB search program conducted from the Southern Hemisphere [1].
Observations were performed at a central frequency of 1400 MHz with 400 MHz of bandwidth, two circular polarizations, using ROACH1-based digital backends [2,3] with a sampling time of 81.92 microseconds. The burst was detected in an observation starting on MJD 60966.207662 (2025-10-18, 04:59:02 UTC). The pulse arrived approximately 905.754 seconds after the start of the observation. The event has a width of ~ 2.4 +/- 0.8 ms and a Dispersion Measure (DM) of 242 +/- 1 pc cm^-3. This excess DM corresponds to an estimated redshift of z ~ 0.18 and a luminosity distance of approximately 870 Mpc (assuming standard cosmology).
The pointing center for the detection is (J2000):
R.A. = 01h 07.7m
Dec. = -46d 33' (-46.55 deg)
(Galactic coordinates: l = 294.61 deg, b = -70.31 deg)
This location is in the general direction of the Sculptor supercluster of galaxies and is centered on the cluster A2870. The localization uncertainty is limited by the primary beam width of the antenna (FWHM ~ 31'). The candidate was identified using the PRESTO software package with a signal-to-noise ratio (SNR) of 8.2 and validated by the FETCH machine learning classifier with a probability of p>0.999. Based on the radiometer equation and observed parameters, we estimate a peak flux density of approximately 3.9 +/-0.9 Jy. RFI mitigation was performed using RFIClean and rfifind in tandem. To confirm the astrophysical nature of the signal, we performed a hierarchical channel-zapping test: we successively masked frequency channels in five stages, removing up to leaving the cleanest 170 MHz of the central band. The signal remained robust against these cuts, confirming its broadband nature and ruling out narrowband RFI.
This is the first FRB detected by the IAR program after analyzing approximately 95 hours of data at this location of the sky during the second half of 2025.
A plot of the pulse profile and dynamic spectrum is available at:
https://ccrgpages.rit.edu/~lousto/cand_tstart_60966.207662037035_tcand_905.7474970_dm_243_snr_8.20.png
References:
[1] https://puma.iar.unlp.edu.ar/
[2] Gancio, G. et al., 2020, A&A, 633, A84
[3] Lousto, C. O. et al., 2024, RMxAC, 56, 134
