Insight-HXMT dedicated 33-day observation of SGR J1935+2154 I. Burst Catalog

Abstract

Magnetars are neutron stars with extreme magnetic field and sometimes manifest as soft gamma-ray repeaters (SGRs). SGR J1935+2154 is one of the most prolific bursters and the first confirmed source of fast radio burst (i.e. FRB 200428). Encouraged by the discovery of the first X-ray counterpart of FRB, Insight-Hard X-ray Modulation Telescope (Insight-HXMT) implemented a dedicated 33-day long ToO observation of SGR

Testing afterglow models of FRB 200428 with early post-burst observations of SGR 1935 + 2154

“…4 we show the times of LOFAR and AARTFAAC observations, overplotted with high-energy bursts observed by various X-ray observatories. One high-energy burst observed by Insight-HXMT (burst number 56 in Cai et al 2022a) occurred during our LOFAR observations on 11/5/2022. The burst had a reported 1-250 keV flux of 2.29 +0.18 −0.17 × 10 −7 erg s −1 cm −2 (Cai et al 2022b).…”

“…FRB 200428 occurred during a very active period of high-energy bursts from SGR 1935+2154, and many hundreds of short X-ray bursts were observed by NICER, Fermi, Swift, AGILE, INTEGRAL, Insight-HXMT, Konus-Wind and other X-ray satellite observatories (Fig. 4; for catalogues of X-ray bursts see Younes et al 2020;Cai et al 2022a;Li et al 2022). Remarkably, an X-ray burst temporally coincident with the FRB was observed by four X-ray instruments: Integral (Mereghetti et al 2020), Insight-HXMT (Li et al 2021), AGILE (Tavani et al 2021) and Konus-Wind (Ridnaia et al 2021).…”

“…The Amsterdam-ASTRON Radio Transient Facility And Analysis Centre (AARTFAAC), is an all-sky radio transient monitor operating in parallel with LOFAR (Prasad et al 2016), sensitive to bright transient and variable emission at low-frequencies. AARTFAAC was operating with 16 subbands spanning 60.15−64.84 MHz during an Xray burst observed from SGR 1935+2154 by Insight-HXMT (burst 19 in Cai et al 2022a). The dispersion delay from SGR 1935+2154 from the Insight-HXMT X-ray band to the AARTFAAC band is 𝜏 X−ray = 324 seconds, and the in-band dispersion delay across 60.15 − 64.84 MHz is 𝜏 in−band = 54 seconds.…”

“…The time of the FRB as observed by CHIME & STARE-2 is denoted by the vertical dashed orange line. We also show counts/fluence and times of X-ray bursts as observed by Insight-HXMT (blue dots;Cai et al 2022a), NICER (red dots;Younes et al 2020) and Fermi-GBM (green dots;Lin et al 2020b). Insight-HXMT data points refer to the total number of photon counts in the burst across all detectors (left y-axis), whereas NICER and Fermi-GBM data points refer to the total fluence of the burst in the 0.5-10 keV and 8-200 keV bands respectively.…”