Timing

0. Table of contents

Last Updated 7 May 2020

1.  Timing Calibrations of X-ray missions

1.1 Summary of Timing Requirement and Calibrations

Mission/Instruments	Science Requirement Absolute Time		Timing System Design		Timing Calibration Status	In-orbit Timing Calibration Targets	Reported Issues	Reference
	Requirement	Goal	GPS Receiver	Clock Stability	(Absolute Timing Precision)
RXTE/PCA
Chandra / ACIS
Chandra / HRC
XMM-Newton/EPIC-MOS
XMM-Newtion/EPIC-PN
INTEGRAL/SPI
INTEGRAL/IBIS
Swift/BAT
Swift/XRT
Suzaku/XIS	No science requirement defined.		No	1.9 x 10^-9 s/s (measured)	Not confirmed.	A0535+262, Her X-1, etc	N/A	Y.Terada et al 2008 (10.1093/pasj/60.sp1.S25)
Suzaku/HXD					360±150 μsec (270±130  μsec in condition)	Crab for coordinated PSR1509-58	Timing shift by a failure in time stamp at the ground station during 2012-2014 (Shu Koyama, Fixed)
NuSTAR/FPM				0.1 ms	0.1 ms		~5ms offset using millisecond pulsars (Lucien Kuiper)
Astrosat
HXMT
Hitomi/SXS, SXI, HXI, SGD	350 μsec	35 μsec	Yes	0.01μsec(GPSR) <3.0 μsec(SpW) 0.3 ns (orbit)	~ 120-230 μsec	Crab (with radio) note: using out-of-time event for SXI	absolute timing accuracy is much larger than expected on ground (3 μsec)	Y.Terada et al 2018 (10.1117/1.JATIS.4.1.011206)
NICER
eROSITA
XRISM/Resolve	1 msec	none	Yes	same as Hitomi		(under discussion)
XRISM/Xtend	10 msec	none	Yes			(under discussion)

 Mission completed.

 Future Mission

1.2 Point of Contacts

2. In-orbit Timing Calibration Plan/Observations

2.1 Archive Data

2.1.1 List of Coordinated Observations useful for Timing

2.1.2 Reports

2.2 New Coordinated Observations

3. Studies on Timing

3.1 effects on timing products (power spec, light curve etc) by the detector’s behavior (dead time, grade selection of calorimeter etc)

4. Timing Tools, (with Statistic Group)

5. Notes