Radio pulsation and imaging study of SGR J1935+2154 with the uGMRT

ATel #13777; Mayuresh Surnis (JBCA, University of Manchester), Bhal Chandra Joshi (NCRA-TIFR), Manjari Bagchi (IMSc), Maura McLaughlin (WVU), Duncan Lorimer (WVU), Harsha Blumer (WVU), Vishal Gajjar (UC Berkeley), Benetge Perera (Arecibo Observatory), P. K. Manoharan (Arecibo Observatory), Benjamin Stappers (JBCA, University of Manchester)
on 3 Jun 2020; 21:02 UT
Credential Certification: Mayuresh Surnis ([email protected])

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Following a series of recent X-ray bursts (Palmer et al., ATEL #13675; Younes et al., ATEL #13678) and the subsequent radio detection of millisecond duration radio bursts with CHIME (Scholz et al., ATEL #13681), STARE2 (Bochenek et al., ATEL #13684) and FAST (Zhang et al., ATEL # 13699), we observed SGR J1935+2154 with the Arecibo Observatory (AO), Green Bank Telescope (GBT) and upgraded Giant Metrewave Radio Telescope (uGMRT) at six epochs. We have already reported non-detections from the AO and GBT observations (Surnis at al., ATEL #13769). Here we report the results from the uGMRT observations. These observations were carried out with the band-4 (550-750 MHz) on 2020 May 27, 10:30 UT and band-5 (1250-1450 MHz) on 2020 May 28, 10:30 UT for an on-source time of three hours in each session. We observed the nearby millisecond pulsar PSR B1937+21 as a test pulsar.

We made radio images of the associated supernova remnant (SNR) G057.2+00.8 with a synthesized beam size of about 4" at band-4 and 1.8" at band-5. We do not detect any continuum emission at the position of the magnetar with 3 sigma flux density upper limits of 90 and 54 microJy at 0.64 and 1.36 GHz, respectively.

We also carried out harmonic and single-pulse search on the beamformed data resulting in non-detection of any significant radio emission. The 10 sigma upper limit for the single-pulse emission with a pulse width of 1 ms is 0.2 Jy ms at 0.64 GHz. The 10 sigma upper limit for the regular pulsed emission for a duty cycle of 10% is 25 microJy at 0.64 GHz. We are still analysing the band-5 beamformed data.

We detected a few strong single-pulses from PSR B1937+21 in the band-4 data. These pulses along with the SNR images are available at the link below.

We thank the staff of the GMRT who have made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research.

Radio images of the SNR and single-pulse detections from PSR B1937+21