XRISM RESOLVE observation 201131010

Title

ON THE ONSET OF THE ACCRETION WAKE IN THE HIGH-MASS X-RAY BINARY VELA X-1

Abstract

We propose a 40-ks XRISM observation of the wind-fed High-Mass X-ray Binary (HMXB) Vela X-1 at orbital phase 0.43-0.53 where we expect the largest changes in absorption as the accretion structure crosses and obstructs our line of sight. By tracing the onset of this structure, we obtain an in-depth view of the stellar wind complexity in this source. In particular, the moderate absorption combined with strong continuum emission happening at these orbital phases will reveal emission lines below 12 keV, even with the gate valve closed. We will follow absorption variability and iron line energy shifts down to the pulse period of the neutron star to probe the onset of the accretion wake on our line of sight and radial velocities of the wind.

FITS header

TELESCOP= 'XRISM   '           / Mission name
INSTRUME= 'RESOLVE '           / Instrument name
FILTER  = 'OPEN    '           / Filter name used
OBS_ID  = '201131010'          / Observation identification string
OBJECT  = 'VELA_X-1'           / Object name
OBSERVER= 'CAMILLE DIEZ'       / PI name
OBS_MODE= 'POINTING'           / POINTING or SLEW or ALL
RA_OBJ  =             135.5283 / [deg] Object Right ascension
DEC_OBJ =             -40.5547 / [deg] Object Declination
RA_PNT  =     135.522754542708 / Pointing RA
DEC_PNT =    -40.5532354916979 / Pointing DEC
RA_NOM  =     135.527956395938 / [deg] Nominal aspect point R.A.
DEC_NOM =    -40.5542773939656 / [deg] Nominal aspect point Dec.
PA_NOM  =     111.343800298812 / [deg] Nominal aspect point roll.
TELAPSE =               105735 / Elapsed time
DATE-OBS= '2024-11-19T01:41:55' / Start date
DATE-END= '2024-11-20T07:04:10' / Stop date
ONTIME  =         59291.976692 / On-source time
EXPOSURE=         59291.976692 / 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    = '2024-12-02T03:40:04' / Date and time this file was created or updated
SIB2_VER= 'V03.01  '           / SIB2 version JAXA

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