Summary of the 12th IACHEC Meeting

TL;DR

The 12th IACHEC meeting summarized advances in high-energy mission calibration, including new standards, improved models, and statistical methods to enhance inter-calibration accuracy across instruments and missions.

Contribution

This report introduces a new calibration standard using SNR 1E0102.2-7219, a novel method for Crab spectrum measurement with NuSTAR, and a statistical approach for instrument inter-calibration.

Findings

Improved ACIS contamination model in CALDB 4.7.3.

First calibration results from Hitomi confirm instrument performance.

A new statistical method aids in aligning effective areas of different instruments.

Abstract

We summarize the outcome of the 12th meeting of the International Astronomical Consortium for High Energy Calibration (IACHEC), held at the UCLA conference center in Lake Arrowhead (California) in March 2017. 56 scientists directly involved in the calibration of operational and future high-energy missions gathered during 3.5 days to discuss the status of the X-ray payload inter-calibration, as well as possible ways to improve it. The "Thermal Supernovas Remnant" (SNR) Working Group presented a recently published paper on 1E0102.2-7219 as a calibration standard in the 0.5-1.0 keV band. A new method to measure the high-energy spectrum of the Crab Nebula and pulsar with NuSTAR without using its optics may yield a new absolute flux standard in the 3-7 keV band. A new ACIS contamination model - released with CALDB version 4.7.3 - leads to a significant improvement in modeling the spectral, spatial, and temporal properties of the contaminant. The first calibration results of the scientific payload on board Hitomi confirm the excellent performance of the instruments before the spacecraft operation problems leading to its loss. Finally, the meeting discussed extensively a novel statistic approach to formally identify in which direction the effective areas of different instruments would need to be changed to bring them into concordance. This method could inform future further calibration efforts.