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Meeting information

  • Date: May 11, 2021 at 07:00 PDT = 10:00 EDT = 14:00 UTC = 16:00 CEST = 22:00 CST = 23:00 JST
  • Connection: Zoom connection circulated by email
  • Attendees: Eric Miller, Catherine Grant, Andy Beardmore, Chen Yong, Gerrit Schellenberger, Hiro Matsumoto, Ivan Valtchanov, Karl Forster, Kristin Madsen, Larry David
  • Next meeting: TBD

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

Agenda

  • Where the Clusters WG left off (from the 2018 IACHEC workshop in Italy: Clusters_WG_report_2018.pdf)
    • eROSITA cross-calibration with clusters
      • Cluster not useful for absolute calibration. 
      • Clusters good for cross-calibration whichis not a high priority
      • A1795 and A2029 are in the calibration program

      • GO time may yield nearby clusters (with a single pointing far beyond the virial radius)

      • Any updates on eROSITA cluster observations that might be useful for IACHEC?
      • (A/I Eric) Contact Konrad about cluster observations and calibration status.
    • Multi-Mission Study
      • 2017 plan was (from Clusters_WG_session_2017_final.pdf):
        • 2017 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
        • 2017 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
        • 2017 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.
          • 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
        • 2017 TASK 5: Extract and process data with May 2017 calibration information. Deadline end of June
        • 2017 TASK 6: Jukka 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.
          NuSTARKarl and Dan WikNuSTAR LP, A2029, A478, A1795, A2199, all completed according to Karl
          (A/I Eric) contact Dan and Karl about NuSTAR data
          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
          NICERCraig (TBC) 
        • (A/I All) Add 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) (Postpone)
        • 2018 TASK 2: Check one cluster with Konrad's methods. Needs isothermal region for simple and accurate modelling. (Postpone)
        • 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 (Postpone)
  • Where do we go from here?
    • Complete multi-mission study?
      • Jukka has the full details of this and is unlikely to share.
      • Any updates on whether Jukka is actively working on this? It was the subject of an AHEAD award.
      • (A/I Ivan) Contact Jukka to find out whether he is working on IACHEC cluster related work.
    • Simply supply data to the concordance effort (Statistics WG)? Probably wants fluxes or flux ratios in a number of energy bands.
    • We need point people for each mission/instrument.
      • See table above.
  • Next meeting
    • Two more WG meetings before September IACHEC meeting in Virginia.
      • If IACHEC is in person but limited to US participants, we will try to have at least one session convenient for Europe and Asia to connect remotely (e.g. early morning local time).
      • Goal is to have data from each mission ready for analysis for ~5 clusters.

 

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