MULTI-MISSION STUDY(XMM/CHANDRA/ROSAT/Suzaku/Swift)

We have a possibility to make one-to-one comparison of a few nearby, relaxed clusters with 5 different 
satellites (XMM/EPIC, CHANDRA/ACIS-I, ROSAT/PSPC, Suzaku/XIS and Swift/XRT). 

Larry agreed to do ACIS-I, Steve agreed to do PSPC, I will do XMM, my student Kimmo Kettula agreed to do 
Suzaku and Andy Beardmore will perhaps do Swift (we need a confirmation on this).

We will use 3-6 arcmin annulus for the extraction of the spectra, so that
- we minimise the scatter from the cool core (we are wasting data, but this enables the comparison with 
  Suzaku which has a larger PSF)
- we minimise the PSF scatter from and to our extraction region (again, dictated by Suzaku)
- we stay in the bright part of the clusters and thus minimise background systematics.

For the comparison, I need the spectra, responses, background and the actual extraction region (arcmin^2) after
the exclusion of point sources, CCD gaps and other dead area.

It would be good to use exactly the same regions for all instruments so that possible spatial variations of the
temperature would cause no significant, additional variation when comparing the measurements from different 
instruments. However, the point sources are variable. In ideal case we should make a combined mask, which 
contains all the regions where any instrument detects significant point sources. I guess this would lead to 
significant data loss, and additionally we would have no emission left in Suzaku, for which we should use 
larger radii for exclusion due to large PSF. Thus, for the March meeting we exclude from each instrument the 
minimal number of point sources required to minimize the point source emission in the 3-6 arcmin annulus. It is
up to each person involved here to estimate this for a given instrument.

For selecting the observations common with the above five missions, we used these criteria:
* The total exposure time must be at least 8 ks to obtain good enough statistics. 
* The center of the cluster must not be too much offset from the center of FOV so that we don't fold in 
  instrument effects which are different between the central and outer regions of the FOV (e.g. vignetting). 

In the following table are listed the obsid:s which have the biggest exposure time and smallest off-axis angle. 
Other obdis:s may be used as well, as long as the cluster center is not more than 3 arcmin away from the 
center of FOV. If the clean exposure is below 10 ks, please use a better observation.

As a cluster center we use the XMM values for A1795, A2029 and PKS0745-19. For Coma we use Steve's ROSAT 
centroid. Please, use these for consistence.


                      A1795 

center           207.22083, 26.590278

                 obsid        off-axis exposure
                              (arcmin)   (ks)
Suzaku/XIS       800012010    0.7      13  
Swift/XRT        00035184002  3.0      13 
ACIS-I           5289         0.1      15
XMM-Newton/EPIC  0097820101   0.2      34
ROSAT/PSPC       RP800105N00  0.5      36
                 RP800055n00  1.8      26


                      A2029 
  
center           227.734167,  5.744639

                 obsid        off-axis exposure
                              (arcmin) (ks)
Suzaku/XIS       804024010    0.5      8  
Swift/XRT        00035187004  2.0      26
ACIS-I           6101         0.0      10
XMM-Newton/EPIC  0551780401   1.0      47        
ROSAT/PSPC       RP800249N00  0.4      13


                      Coma

center           194.9447, 27.932632

                 obsid        off-axis exposure
                              (arcmin) (ks)
Suzaku/XIS       801097010    1.9      179        
Swift/XRT        00035172001  1.9      10  
ACIS-I           13996        1.1      125         
XMM-Newton/EPIC  0300530301   0.5      31 
ROSAT/PSPC       RP800005N00  2.3      21
             
    
                         PKS0745-19   

center           116.88051 -19.294847     

                 obsid        off-axis exposure
                              (arcmin) (ks)
Suzaku/XIS       802062010    0.4      32        
Swift/XRT        00051650023  0.9      15 
ACIS-I           6103         0.1      10          
XMM-Newton/EPIC  0105870101   0.2      28        
ROSAT/PSPC       RP800623N00  0.3      10