1. The IACHEC Matteo Guainazzi XMM-Newton Science Operations Centre ESAC-ESA

2. Outline 1.What is the IACHEC? 2.How does it work? 3.What do we want to achieve? 4.Examples of cross-calibration results made possible by the IACHEC 5.How can you participate?

3. What it is? The IACHEC is the International Astronomical Consortium for High- Energy Calibration It is a shared undertaking among high-energy calibrators to coordinate (and therefore strengthen) our work It acts as a forum where astronomers involved in calibration of past, present (operational) and future missions work together to improve the cross-calibration among their instruments Past missions: ASCA, BeppoSAX, ROSAT Operational missions: Chandra, Fermi, Integral, MAXI, RXTE, Suzaku, Swift, XMM-Newton Future missions: Astro-H, eRosita, GMES, NuStar, IXO It is not directly funded by any Agencies or institutions. Individual projects/missions contribute through the work and mission budget of their calibration teams Strongly endorsed by the Chandra and XMM-Newton User’s Group

4. How does it work? 1.Through Working Groups, which: a.Define calibration standards and procedures b.Organize observational cross-calibration campaigns c.Define astrophysical models for X-ray “standard candles” d.Publish cross-calibration results on refereed journal papers, so as to provide the community with peer-reviewed references on the calibration and cross-calibration quality e.Maintain and update cross-calibration results on public Wiki pages 2.Through yearly meetings where: a.The calibration status of each operational mission is presented b.Working Groups meet (primarily) to finalize the publication of cross- calibration papers, review the status of ongoing, or start new projects c.The development status of future missions is presented (with particular focus on their calibration plan) d.Theoretical astrophysicists are invited to validate/challenge the astrophysical assumptions underlying our calibration work

5. Working Groups CCD issues (Chair: Catherine Grant). It aims to provide a forum for cross-mission discussion and comparison of CCD-specific modeling and calibration issues, lessons learned, and best practices. CCD issuesCatherine Grant Clusters (Chair: Jukka Nevalainen). It aims at a systematic comparison of cluster temperatures measured by Chandra and XMM-Newton, with a possible extension of this comparison to Suzaku in the nearby future. ClustersJukka Nevalainen Effective area (Chairs: Manabu Ishida and Hermann Marshall). It aims at the analysis of the Chandra, Suzaku and XMM-Newton cross-calibration campaign data on PKS2155-304 collected so far. Effective areaManabu IshidaHermann Marshall High Resolution (Chair: Andy Pollock). It aims at a complete census of emission lines in the RGS and LETG spectrum of Capella. High ResolutionAndy Pollock Isolated Neutron Stars (Chair: Frank Haberl). It aims at the cross-calibration analysis of the RXJ1854.5-3754 spectra Isolated Neutron StarsFrank Haberl Non-Thermal SNR (Chairs: Lorenzo Natalucci and Masahiro Tsujimoto). It aims at the cross-calibration analysis of G21.5-0.9 (mainly below 10 keV) and of the Crab (mainly above 10 keV) spectra. Non-Thermal SNRMasahiro Tsujimoto Thermal SNR (Chair: Paul Plucinsky): analysis of 1E0102.2-7219 Thermal SNRPaul Plucinsky White Dwarfs (Chair: Vadim Burwitz). It aims at comparing atmospheric models in conjunction with analysis of high-resolution data. White DwarfsVadim Burwitz

6. What would we like to achieve? 1.Improve the calibration of our instruments In modern X-ray astronomy “calibration” is “cross-calibration” 2.Provide the astronomical community at large with reliable sources of information on calibration accuracy and systematics in all domains: imaging, spectral, timing 3.Ensure that state-of-the-art astrophysical understanding of celestial sources is assumed when analyzing on-flight calibration data 4.Ensure that statistics is properly used when analysing calibration data 5.Avoid reinventing the wheel: share common problems, find common solutions 6.Make sure that we use the power of all existing data when calibrating 7.Share experience, know-how and “lessons-learned” from past and operational missions with teams working on future missions 8.Create a cooperation rather then a competition atmosphere across calibration teams Traditionally, calibration had been conceived as an “internal project matter”. Very often, cross-calibration among different instrument was evaluated a posteriori by the community. In 2006 Marcus Kirsch and Steve Sembay promoted the IACHEC to:

7. Gallery of IACHEC results: 1E0102-72 OVII OVIII NeIX NeX (Plucinsky et al., 2009)

8. Gallery of IACHEC results: clusters (Nevalainen et al., 2010)

9. Gallery of IACHEC results: G21.5-0.9 (Tsujimoto et al. 2011)