Summary of the 2015 IACHEC meeting

TL;DR

This paper summarizes the 2015 IACHEC meeting, focusing on high-energy calibration status, inter-calibration discrepancies between X-ray missions, and recent multi-mission comparison results.

Contribution

It provides an overview of calibration issues, recent studies on inter-mission calibration consistency, and progress in cross-calibration of high-energy X-ray instruments.

Findings

Calibration of effective area shape above 2 keV is consistent between XMM-Newton and Chandra.

Significant calibration discrepancies exist below 2 keV, affecting temperature measurements.

Multi-mission comparison of the Crab Nebula shows +/-13% agreement in relative normalization.

Abstract

We summarize the outcome of the 10th meeting of the International Astronomical Consortium for High Energy Calibration (IACHEC), held in Beijing (People's Republic of China) in April 2015. Over 80 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. A recent study on a large sample of galaxy clusters confirmed that the calibration of the effective area shape above 2 keV between XMM-Newton/EPIC and Chandra/ACIS is consistent, but showed a significant discrepancy at lower energies. Temperatures measured by EPIC are therefore smaller, the difference being largest for the highest temperatures, up to ~20% at kT=10 keV (Schellenberger et al. 2015). The latest multi-mission study of the Crab Nebula above 10 keV shows a +/-13% agreement in the relative normalization of the INTEGRAL, NuSTAR, RXTE, and {\it Suzaku} hard X-ray instruments.