Meeting information

  • Date: Wednesday, May 15, 2024 at  18:00–19:30 CEST

  • Location: Parador de La Granja, La Granja, Spain (Room 2)

  • Connection: Zoom connection circulated by email

  • Attendees: TBD
  • Next meeting: TBD

Minutes are shown in magenta.
Action items are shown in red.

Agenda

  • Brief discussion of eROSITA + XMM + Chandra cluster temperature comparison: https://ui.adsabs.harvard.edu/abs/2024arXiv240117297M/abstract (Konrad, Michael, Gerrit?)
    • Konrad: starting next week will check results for largest outliers, does not agree with results from other sources; ground calibration suggests eROSITA ARF adjustments of this magnitude are not possible
    • We should invite Konstantinos Mikgas or Gerrit to present these results at a Zoom meeting in a few months
  • Status of Multi-Mission Study
    • 2017 plan was (from Clusters_WG_session_2017_final.pdf):
      • TASK 1: Define the extraction radius
        • Statistics requirement and PSF minimisation prefer bigger values
        • bkg and vignetting minimisation prefer smaller values
        • Extraction radius = 6 arcmin
      • TASK 2: Define a suitable cluster
        • Hot enough (minimise 1 keV line emission, better src/to bkg at 7 keV energies
        • Not too distant to yield enough photons
        • Preferably low NH... if high, harder to get enough photons at the lowest energies. But we can cut the low energy band and use the rest. No requirement for NH at the moment
        • kT > 6 keV z < 0.1
      • TASK 3: Define a suitable observation
        • Long enough for statistics.
        • Cluster center – FOV center offaxis minimised
        • Proceed with single on-axis observations. If too constraining (not enough clusters with enough counts) we will discuss about merging several observations.
        • 100000 c in central 6 arcmin (40000 for PSPC)
        • Offaxis < 3 arcmin
      • Following PRELIMINARY! list consists hot nearby clusters from HIFLUGCS sample, following these criteria:
        • kT > 6 keV, except for Perseus
        • Offset btw. the cluster center and pointing FOV center < 3 arcmin
        • Exposure > 10 ks in the available data
        • Clusters in the list above are not only HIFLUGCS from Gerrit's paper, so some added, maybe Jukka added some in the Galactic plane.
        • Swift now has lots of data on PKS0745.
        • Chandra has lots of data on A1795.
        • Add A2199 to the sample? Probably cooler than 6 keV, but also probably observed by many missions.
        • Ivan has worked on A1795, adjusting work flow, also worked on chip gap/bad pixel correction on pn using image from MOS, reduces the effect on the ARF to 0.1% (link to technical note: https://arxiv.org/abs/2103.01753)
      • 2017 TASK 4: Compile a list of available clusters and obs. ID:s fulfilling our criteria: Larry (Chandra), Eric (Suzaku), Andy B. (Swift), Steven Snowden (ROSAT), Jukka (XMM) Deadline end of April
      • TASK 5: Extract and process data with May 2024 calibration information. Deadline: ???
      • TASK 6: Eric will do the stack residuals ratio analysis.
      • (A/I All) Update compiled list of available clusters and ObsIDs fulfilling our criteria: 

         

        InstrumentContact PersonNotes
        XMM EPIC MOS & pnIvan
        Chandra ACISLarry & Gerrit
        Suzaku XISEric
        Swift XRTAndy B.
        ROSAT PSPC?(A/I Eric) Ask Konrad and Michael F. about ROSAT cluster person. Kip suggest Steve Snowden.
        NuSTARDanNuSTAR LP, A2029, A478, A1795, A2199, all completed according to Karl
        eROSITA?(A/I Eric) Ask Konrad and Michael F. about eROSITA cluster person and data set.
        ASTROSATGulab
        HXMTChen YongOnly two clusters have been observed: Coma, Perseus; but FoV is probably too large with collimator, so hard to compare with imaging instruments
        NICERCraig (TBC)
        XRISMEricResolve is a problem due to small FOV; Xtend is possible, but will have to wait until 2025
        EP FXTChen YongA1795, A3571 are done; will observe Perseus, A2029
      • Added A2199 to the sample
        • Probably cooler than 6 keV, but also probably observed by many missions.
    • 2018 summary used just XMM EPIC pn vs. ROSAT PSPC, just 6 arcmin extraction radius
    • Action items from 2018
      • 2018 TASK 1: Check ROSAT PSPC calibration using one of our clusters (Jukka & M. Freyberg) (Postponed)
      • 2018 TASK 2: Check one cluster with Konrad's methods. Needs isothermal region for simple and accurate modelling. (Postponed)
      • 2018 TASK 3: Swift XRT flux weighting of ARFs (A/I Andy B.) XRT mkarf doesn't flux-weight ARFs, so Andy has to figure out how to do this by hand.
      • 2018 TASK 4: Draft ready by next IACHEC (Postponed)
  • other business
    • Data for the concordance effort (CalStats WG)? Probably wants fluxes or flux ratios in a number of energy bands.
    • This should be done as part of the MMS.
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