A simple, flexible method for timing cross-calibration of space missions

Abstract

The timing (cross-)calibration of astronomical instruments is often done by comparing pulsar times-of-arrival (TOAs) to a reference timing model. In high-energy astronomy, the choice of solar system ephemerides and source positions used to barycenter the photon arrival times has a significant impact on the procedure, requiring a full reprocessing of the data each time a new convention is used. Our method, developed as part of the activities of the International Astronomical Consortium for High Energy Calibration (IACHEC), adapts an existing pulsar solution to arbitrary JPL ephemerides and source positions by simulating geocentric TOAs and refitting timing models (implemented with PINT). We validate the procedure and apply it to thousands of observations of the Crab pulsar from 15 missions spanning 1996--2025, demonstrating inter-ephemeris TOA consistency at the $\lesssim 5\mu$s level, using the DE200/FK5-based Jodrell Bank Monthly Ephemeris as a common reference. We release the TOAExtractor open-source tool and a TOA database to support future calibration and scientific studies. Instrument timing performance is broadly consistent with mission specifications; the X-ray-to-radio phase offset varies with energy and time at a level that is marginally consistent with the uncertainties of the radio ephemeris, motivating coordinated multiwavelength follow-up.

22 pages, 7 figures, 4 tables. Published in PASP

References in corpus (42)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• TEMPO2, a new pulsar timing package. I: Overview
• The second data release from the European Pulsar Timing Array III. Search for gravitational wave signals
• The Second Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
• Tempo2, a new pulsar timing package. II: The timing model and precision estimates
• Binary and Millisecond Pulsars
• The NANOGrav 15-year Data Set: Observations and Timing of 68 Millisecond Pulsars
• Stingray: A Modern Python Library For Spectral Timing
• Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars
• PINT: A Modern Software Package for Pulsar Timing
• In-Orbit Performance of MAXI Gas Slit Camera (GSC) on ISS
• The Soft State of Cygnus X-1 Observed with NuSTAR: A Variable Corona and a Stable Inner Disk
• A Precise Proper Motion for the Crab Pulsar, and the Difficulty of Testing Spin-Kick Alignment for Young Neutron Stars
• A pulsar-based timescale from the International Pulsar Timing Array
• Pulsar Timing for the Fermi Gamma-ray Space Telescope
• Absolute Timing of the Crab Pulsar with RXTE
• Broadband X-ray Imaging and Spectroscopy of the Crab Nebula and Pulsar with NuSTAR
• The neutron star mass, distance, and inclination from precision timing of the brilliant millisecond pulsar J0437$-$4715
• X-ray and Radio Timing of the Pulsar in 3C 58
• Review of X-ray pulsar spacecraft autonomous navigation
• SciServer: a Science Platform for Astronomy and Beyond
• Absolute timing with IBIS, SPI and JEM-X aboard INTEGRAL
• In Orbit Timing Calibration of the Hard X-Ray Detector on Board Suzaku
• All at once: transient pulsations, spin down and a glitch from the Pulsating Ultraluminous X-ray Source M82 X-2
• Detection and timing of gamma-ray pulsations from the $707$ Hz pulsar J0952$-$0607
• Absolute timing of the Crab pulsar with the INTEGRAL/SPI telescope
• High-Precision X-ray Timing of Three Millisecond Pulsars with NICER: Stability Estimates and Comparison with Radio
• The relative and absolute timing accuracy of the EPIC-pn camera on XMM-Newton, from X-ray pulsations of the Crab and other pulsars
• Timing Calibration of the NuSTAR X-ray Telescope
• PSR J1906+0722: An Elusive Gamma-ray Pulsar
• Proper Motion of the Crab Pulsar Revisited
• In-orbit timing calibration of the Insight-Hard X-ray Modulation Telescope
• Hitomi X-ray studies of Giant Radio Pulses from the Crab pulsar
• The Radio Parallax of the Crab Pulsar: A First VLBI Measurement Calibrated with Giant Pulses
• Timing accuracy of the Swift X-Ray Telescope in WT mode
• NinjaSat monitoring of Type-I X-ray bursts from the clocked burster SRGA J144459.2$-$604207
• NinjaSat: Astronomical X-ray CubeSat Observatory
• Time Assignment System and Its Performance aboard the Hitomi Satellite
• Development of the Timing System for the X-Ray Imaging and Spectroscopy Mission
• Absolute Time Calibration of LAXPC aboard AstroSat

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