ESTABLISHING THE PRESENCE OF EXCRETION FLOW IN X-RAY BINARIES WITH RESOLVE SPECTROSCOPY OF CIRCINUS X-1
In X-ray binaries, the presence of the excretion (outward) flow is theoretically envisioned as inevitable. The excretion flow has been entirely ignored despite its firm theoretical ground, but recent observations point toward the presence of it. Convincing evidence was obtained with the NICER observations of the neutron star binary Cir X-1. Physical properties of the excretion flow can be constrained with two high-resolution X-ray spectra taken at different orbital phases. The diagnostic requires a spectral resolution of R = E/DE ~ 10^3 in 2-8 keV band, which can only be achieved with Resolve. One of the two observations was already executed in the PV phase, and we propose the other one in the AO1 cycle, to verify the presence of the excretion flow.
TELESCOP= 'XRISM ' / Mission name INSTRUME= 'RESOLVE ' / Instrument name FILTER = 'ND ' / Filter name used OBS_ID = '201036010' / Observation identification string OBJECT = 'CIR_X-1 ' / Object name OBSERVER= 'NAGI ATSUCHI' / PI name OBS_MODE= 'POINTING' / POINTING or SLEW or ALL RA_OBJ = 230.1702 / [deg] Object Right ascension DEC_OBJ = -57.1667 / [deg] Object Declination RA_PNT = 230.161119782972 / Pointing RA DEC_PNT = -57.1666525100199 / Pointing DEC RA_NOM = 230.168602185828 / [deg] Nominal aspect point R.A. DEC_NOM = -57.1671505958914 / [deg] Nominal aspect point Dec. PA_NOM = 103.573681922342 / [deg] Nominal aspect point roll. TELAPSE = 157388.963571995 / Elapsed time DATE-OBS= '2025-02-13T07:40:00' / Start date DATE-END= '2025-02-15T03:23:08.963572' / Stop date ONTIME = 76298.895346 / On-source time EXPOSURE= 76298.895346 / 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 = '2025-02-19T07:09:16' / Date and time this file was created or updated SIB2_VER= 'V03.01 ' / SIB2 version JAXA