http://arxiv.org/abs/2005.03517
We have performed a multi-wavelength study of supernova remnant (SNR) G57.2+0.8 hosting the magnetar SGR 1935+2154, which emitted an extremely bright ms-duration radio burst on Apr 28, 2020 (Scholz & Chime/Frb Collaboration 2020; Bochenek et al. 2020). We used the 12CO and 13CO J=1-0 data from the MWISP CO line survey to search for molecular gas associated G57.2+0.8, in order to constrain the physical parameters (e.g., the distance) of the SNR and its magnetar. We report that SNR G57.2+0.8 is likely impacting the molecular clouds (MCs) at the local standard of rest (LSR) velocity V_{LSR} ~ 30 km/s and excites a weak 1720 MHz OH maser. The LSR velocity of the MCs places the SNR and magnetar at a kinematic distance of d=6.6 +/- 0.7 kpc. The non-detection of thermal X-ray emission from the SNR and the relatively dense environment suggests G57.2+0.8 be an evolved SNR with an age $t>1.6 \times 10^4$ (d/6.6 kpc) yr. The explosion energy of G57.2+0.8 is lower than $2 \times 10^{51}(n_0/10 cm^{-3})^{1.16} (d/~6.6 kpc)^{3.16}$ erg, which is not very energetic even assuming a high ambient density $n_0$ = 10 cm$^{-3}$. This reinforces the opinion that magnetars do not necessarily result from very energetic supernova explosions.
P. Zhou, X. Zhou, Y. Chen, et. al.
Fri, 8 May 20
66/72
Comments: 8 pages, 5 figures, submitted