FAST non-detection of 1E1841-045 following its high-energy reactivation
ATel #16799; W. W. Zhu (NAOC), J. H. Cao (NAOC), J. R. Niu (NAOC), Y. K. Zhang (NAOC), T. C. Wang (BNU), C. F. Zhang (NAOC), D. K. Zhou (ZJL), Q. Wu (NJU), Z. W. Wu (NAOC), L. Lin (BNU), D. J. Zhou(NAOC), H. Xu(NAOC), Y. Feng(ZJL), Y. X. Huang (YNU), R. Luo (GZU) P. Wang (NAOC), D. Li (NAOC), J. L. Han(NAOC), K. J. Lee(PKU), B. Zhang (UNLV)
on 4 Sep 2024; 12:32 UT
Credential Certification: Weiwei Zhu (zhuww@nao.cas.cn)
Subjects: Radio, Magnetar
Referred to by ATel #: 16927
Following the recent reactivation of magnetar 1E1841-045 in X-ray and Gamma-ray (GCN #37222, ATEL #16784 #16786 #16789) observed by Swift, Fermi, and NICER team, the FAST FRB key science project team observed the magnetar using the center beam of the 19-beam L-band receiver onboard the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We observed the target three times: 35 min starting from UTC2024-08-23 13:17:00, 60~min starting from UTC2024-08-29 11:49:00, and 30 min starting from UTC2024-09-01 11:40:00 with 49.152 us time resolution and a 0.122 MHz channelization in the 1.05-1.45GHz band. We detected no significant radio burst with dispersion measure between 5 and 5000 pc cm^{-3} and an S/N>7 sigma, equivalent to a burst fluence limit of about 17.5 mJy ms for a fiducial burst width of 1 ms. We also searched for pulsed radio emission with the spin period of the magnetar (11.8 s). We found no significant signal with S/N>5, equivalent to a pulsed flux limit of 11 uJy, assuming a fiducial pulse duty cycle of 10 percent. Our results indicate that the magnetar was probably not active in Radio when we observed it; we will continue observing this target.
