FAST detection of radio bursts and pulsed emission from SGR J1935+2154

ATel #14084; Weiwei Zhu(NAOC), Bojun Wang(PKU), Dejiang Zhou(NAOC), Heng Xu(PKU), Pei Wang(NAOC), Yongkun Zhang(NAOC), Yi Feng(NAOC), Jinlin Han(NAOC), Jinchen Jiang(PKU), Kejia Lee(PKU), Di Li(NAOC), Lin Lin(BNU), Yunpeng Men(PKU), Jiarui Niu(NAOC), Renxin Xu(PKU), Yuanpei Yang(YNU), Wenfei Yu(SHAO), Binbin Zhang(NJU), Bing Zhang(UNLV), Chunfeng Zhang(PKU), Bing Zhang(UNLV), Chunfeng Zhang(PKU)
on 10 Oct 2020; 16:45 UT
Credential Certification: Weiwei Zhu (zhuww@nao.cas.cn)

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SGR J1935+2154, the host magnetar of the Galactic FRB200428 (ATel #13681, #13684), was reported to be radio-active again on 2020 Oct 8th by CHIME/FRB team (ATel #14074, #14080). There was one marginal detection of the magnetar's pulsed radio emission at 408 MHz by the Medicina Northern Cross (ATel #13783) despite many attempts (ATel #13713, #13726, #13778, #13838). FAST observed this magnetar for one hour on 2020 Oct 9th at 1.25 GHz with a bandwidth of 460MHz and detected multiple radio pulses with fluence up to 40 mJy ms. We also searched for *periodical* radio emission from this magnetar and found a period of 3.24781(1)s (https://crafts.bao.ac.cn/news/20201009_SGR1935+2154/1.jpg). The pulses detected by FAST on Oct 9th are well aligned to within 0.03 of the spin phase. Since the discovery of the Galactic FRB200428, FAST observed SGR J1935+2154 for 15 hours in April and May, and 2 hours in Aug and successfully detected one highly polarized pulse on 2020 April 30 (Zhang et al. ATel #13699). The detection of multiple bursts from 1-hour observation indicates a significant increase in low fluence bursting activity from this magnetar. The detected single pulses aligned well with the pulse period suggests that the pulsed emission is genuine. Based on these results and the increasing bursting activities, we speculate that the magnetar may be in the process of turning into an active radio pulsar. FAST will continue to monitor the source in the following days. Detailed data analysis will be reported later.

Figure 1. SGR1935+2154 Pulsed Radio Emission.