INVESTIGATING THE NATURE OF NI-RICH SNR G349.7+0.2: SEARCHING FOR FIRST ROBUST EVIDENCE OF ELECTRON-CAPTURE EXPLOSION
Although a textbook explanation says that stars with a mass between 8-30M_sun explodes as a standard core-collapse supernova (SN), the true mass range is still unknown: stars with masses at the lower limit of this range are believed to experience electron capture SN and such SNe is thought to eject large amount of nickel (Ni) during the explosion. Here we propose an observation of G349.7+0.2, whose Ni abundance is highest among all the SNRs. While our previous analysis has large uncertainties, XRISM has the capability to accurately determine the yields of Fe-group elements and their velocity structures, providing valuable insights into the lower mass limit for standard SNe and potentially offer the first robust evidence of electron capture SN in our Galaxy.
TELESCOP= 'XRISM ' / Mission name INSTRUME= 'RESOLVE ' / Instrument name FILTER = 'FE55 ' / Filter name used OBS_ID = '201041020' / Observation identification string OBJECT = 'G349.7+0.2' / Object name OBSERVER= 'HIROYUKI UCHIDA' / PI name OBS_MODE= 'POINTING' / POINTING or SLEW or ALL RA_OBJ = 259.5009 / [deg] Object Right ascension DEC_OBJ = -37.4391 / [deg] Object Declination RA_PNT = 259.495767580166 / Pointing RA DEC_PNT = -37.4395185579535 / Pointing DEC RA_NOM = 259.500881568942 / [deg] Nominal aspect point R.A. DEC_NOM = -37.439050597051 / [deg] Nominal aspect point Dec. PA_NOM = 90.0016561206409 / [deg] Nominal aspect point roll. TELAPSE = 296018.722472996 / Elapsed time DATE-OBS= '2025-03-05T00:38:14' / Start date DATE-END= '2025-03-08T10:51:52.722473' / Stop date ONTIME = 11773.598013 / On-source time EXPOSURE= 11773.598013 / Exposure time PROCVER = '03.00.013.010' / Processing script version MKFFF = 'ISAS/JAXA' / Origin of First FITS file ORIGIN = 'GSFC/NASA' / Origin of Processed FITS file SOFTVER = 'Hea_21Aug2024_V6.34_XRISM_21Aug2024_V001' / Version of HEADAS used CALDBVER= 'gen20241115_xtd20241115_rsl20241115' / Version of CALDB used DATE = '2025-03-28T08:32:36' / Date and time this file was created or updated SIB2_VER= 'V03.01 ' / SIB2 version JAXA