XRISM XTEND observation 201090010

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Xtend spectrum

p0300: All four CCDs in full window mode

p0300: All four CCDs in full window mode

Xtend light curve

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Light curve

Title

DIRECT MEASUREMENT OF WHITE DWARF MASSES WITH XRISM: GRAVITATIONALLY REDSHIFTED 6.4 KEV LINE IN RT CRU

Abstract

The goal of the proposed XRISM observation is to show that high-resolution X-ray spectroscopy can directly reveal the mass of an accreting white dwarf (WD). By measuring the centroids of Fe Ka and Kb; fluorescent lines reflected from the WD, we will determine the gravitational redshift at the WD surface and hence the WD mass in RT Cru, the most hard-X-ray luminous symbiotic binary star. The mass of this WD is thought to be above the likely upper limit for its birth mass. Confirmation of this situation would imply that the mass is almost certainly increasing, establishing a subset of symbiotic stars as viable progenitors for some Type Ia supernovae. Because this project uses emission lines in the 6-7 keV range, it is minimally impacted by the Gate Valve remaining in the closed configuration

FITS header

TELESCOP= 'XRISM   '           / Mission name
INSTRUME= 'XTEND   '           / Instrument name
OBS_ID  = '201090010'          / Observation identification string
OBJECT  = 'RT_CRU  '           / Object name
OBSERVER= 'JENNIFER SOKOLOSKI' / PI name
OBS_MODE= 'POINTING'           / POINTING or SLEW or ALL
RA_OBJ  =             188.7239 / [deg] Object Right ascension
DEC_OBJ =             -64.5656 / [deg] Object Declination
RA_PNT  =     188.727011493866 / Pointing RA
DEC_PNT =    -64.5635674672453 / Pointing DEC
RA_NOM  =     188.723895663622 / [deg] Nominal aspect point R.A.
DEC_NOM =    -64.5657614409595 / [deg] Nominal aspect point Dec.
PA_NOM  =     261.577136688067 / [deg] Nominal aspect point roll.
TELAPSE =               369415 / Elapsed time
DATE-OBS= '2025-06-09T12:54:34' / Start date
DATE-END= '2025-06-13T19:31:29' / Stop date
ONTIME  =         153453.14153 / On-source time
EXPOSURE=         153453.14153 / Exposure time
PROCVER = '03.02.014.010'      / Processing script version
MKFFF   = 'ISAS/JAXA'          / Origin of First FITS file
ORIGIN  = 'GSFC/NASA'          / Origin of Processed FITS file
SOFTVER = 'Hea_12Mar2025_V6.35_XRISM_28Feb2025_V002' / Version of HEADAS used
CALDBVER= 'gen20241115_xtd20241115_rsl20241115' / Version of CALDB used
DATE    = '2025-07-14T09:07:48' / Date and time this file was created or updated
SIB2_VER= 'V03.01  '           / SIB2 version JAXA

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