Detection of 9 new bursts from FRB20201124A with the 100 m Effelsberg Telescope

ATel #14933; Robert Main (MPIfR), Suryarao Bethapudi (MPIfR), Viswesh Marthi (NCRA)
on 23 Sep 2021; 20:58 UT
Credential Certification: Robert Main (ramain@mpifr-bonn.mpg.de)

Tweet

We report on the detection of 9 bursts from FRB20201124A at 1.2 - 1.6 GHz with the Effelsberg 100m telescope. The observations spanned 5 hours beginning at 2021-09-21T01:00:00 UTC, and the burst fluences were in the range of ~1 - 12 Jy ms, suggesting a rate of ~1.8 bursts per hour above 1 Jy ms. These detections were followed by a CHIME detection later on the same day, as reported on the CHIME/FRB repeaters webpage (https://www.chime-frb.ca/repeaters/FRB20201124A). This follows 4 months of no detections, including during targeted observations with both uGMRT (2 hours of total exposure) and Effelsberg (20 hours of total exposure) in the interim.

During March-May 2021, FRB20201124A was the most active known FRB, at times with burst detection rates greater than ~10 / hour. The CHIME announcement of heightened activity (ATEL #14497) triggered extensive follow up, leading to the reporting of precise interferometric positions (ATEL #14592, #14526, #14538, #14603). The recent detections may indicate that the source is entering another period of heightened activity. If similar to March-May 2021, the source may be active for weeks to months, and now may be a fruitful time for targeted observations of the source.

Below we link de-dispersed dynamic spectra plots showing the bursts. The frequency axis is cropped to 1.25 - 1.5 GHz. Timestamps in the inset are the topocentric time-of-arrival when de-dispersed to the top of the band.

http://www.ncra.tifr.res.in/~viswesh/FRB20201124A/Atel2021Sept21_burstpanorama.pdf

Below we plot the burst rate over time. CHIME/FRB rates were computed using the timestamps on the CHIME/FRB repeaters webpage and assuming a daily exposure of 20mins. uGMRT detections of MJD59309 are described in Marthi et al. 2021. Effelsberg detections of MJD59313 in Hilmarsson et al. 2021. The downwards pointing arrows denote observations with non-detections.

http://www.ncra.tifr.res.in/~viswesh/FRB20201124A/Atel2021Sept21_rateplot.pdf