Journal Article

Contemporaneous X-Ray Observations of 30 Bright Radio Bursts from the Prolific Fast Radio Burst Source FRB 20220912A

Scholz, Paul, Cook, Amanda M, Gaensler, B. M, Bhardwaj, Mohit, Lazda, Mattias, Abbott, Thomas C, Eadie, Gwendolyn, Stairs, Ingrid, Pearlman, Aaron B, Michilli, Daniele, Tan, Chia Min, Pandhi, Ayush, Stenning, David C, Shin, Kaitlyn, Sammons, Mawson W, Kaspi, Victoria M, Cruces, Marilyn, Rafiei-Ravandi, Masoud, Smith, Kendrick, Cassanelli, Tomas, Masui, Kiyoshi W, Ibik, Adaeze L, Dong, Fengqiu Adam, Curtin, Alice P

2024

Overview

We present an extensive contemporaneous X-ray and radio campaign performed on the repeating fast radio burst (FRB) source FRB 20220912A for 8 weeks immediately following the source’s detection by CHIME/FRB. This includes X-ray data from XMM-Newton, NICER, and Swift, and radio detections of FRB 20220912A from CHIME/Pulsar and Effelsberg. We detect no significant X-ray emission at the time of 30 radio bursts with upper limits on a 0.5–10.0 keV X-ray fluence of (1.5–14.5) × 10−10 erg cm−2 (99.7% credible interval, unabsorbed) on a timescale of 100 ms. Translated into a fluence ratio η x/r = F X-ray/F radio, this corresponds to η x/r < 7 × 106. For persistent emission from the location of FRB 20220912A, we derive a 99.7% 0.5–10.0 keV isotropic flux limit of 8.8 × 10−15 erg cm−2 s−1 (unabsorbed) or an isotropic luminosity limit of 1.4 × 1041 erg s−1 at a distance of 362.4 Mpc. We derive a hierarchical extension to the standard Bayesian treatment of low-count and background-contaminated X-ray data, which allows the robust combination of multiple observations. This methodology allows us to place the best (lowest) 99.7% credible interval upper limit on an FRB η x/r to date, η x/r < 2 × 106, assuming that all 30 detected radio bursts are associated with X-ray bursts with the same fluence ratio. If we instead adopt an X-ray spectrum similar to the X-ray burst observed contemporaneously with FRB-like emission from the Galactic magnetar SGR 1935+2154 detected on 2020 April 28, we derive a 99.7% credible interval upper limit on η x/r of 8 × 105, which is only 3 times the observed value of η x/r for SGR 1935+2154.

• Publisher: IOP Publishing
• Subject: Astronomy / Astrophysics / Collaboration / Electrical engineering / Emission / Fluence / Luminosity / Magnetars / Neutron stars / Observatories / Pulsars / Radio bursts / Stars & galaxies / X ray spectra / X-ray astronomy / X-ray bursts / X-ray emissions / X-rays / XMM (spacecraft)