DYNAMICAL STATE OF A UNIQUE COOLING-FLOW GALAXY CLUSTER AT Z~0.6
We propose a 250 ksec observation of the Phoenix cluster at z=0.597, the most X-ray luminous galaxy cluster as well as the only cooling flow cluster known to date. By combining Fe XXV and Fe XXVI lines, we will be able to measure velocities both inside and outside the cool core, thereby complementing the lack of spatial resolution of XRISM by its spectral capability. Our goals include testing if (i) turbulent heating can be a generic mechanism for heating the cool core, (ii) hydrostatic equilibrium is valid for this apparently quiescent system, and (iii) there are any large-scale structures associated with the most massive galaxy cluster at z~0.6. The proposed XRISM observation will provide unprecedented view of the distant diffuse Universe even with the closed Gate Valve configuration.
TELESCOP= 'XRISM ' / Mission name INSTRUME= 'RESOLVE ' / Instrument name FILTER = 'OPEN ' / Filter name used OBS_ID = '201022010' / Observation identification string OBJECT = 'SPT-CL_J2344-4243' / Object name OBSERVER= 'TETSU KITAYAMA' / PI name OBS_MODE= 'POINTING' / POINTING or SLEW or ALL RA_OBJ = 356.1829 / [deg] Object Right ascension DEC_OBJ = -42.72 / [deg] Object Declination RA_PNT = 356.179552268878 / Pointing RA DEC_PNT = -42.7237930806993 / Pointing DEC RA_NOM = 356.183010195649 / [deg] Nominal aspect point R.A. DEC_NOM = -42.7205910298077 / [deg] Nominal aspect point Dec. PA_NOM = 45.0032163309829 / [deg] Nominal aspect point roll. TELAPSE = 580014.801108986 / Elapsed time DATE-OBS= '2025-04-27T05:35:33' / Start date DATE-END= '2025-05-03T22:42:27.801109' / Stop date ONTIME = 274738.03072 / On-source time EXPOSURE= 274738.03072 / 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 = '2025-07-13T17:36:02' / Date and time this file was created or updated SIB2_VER= 'V03.01 ' / SIB2 version JAXA