National Aeronautics and Space Administration

EXOSAT Medium Energy Proportional Counter

Data products

• Lightcurves : During a typical EXOSAT observation, several configurations for the ME array detector were possible as well as different on board computer set up. Separate lightcurve were accumulated for any change in either the mechanical ME configuration and/or different on board computer programs. All the lightcurves are background subtracted and dead time corrected. Four data sets of on-source lightcurves are available. One set has 30 sec time resolution obtained over 0.8-9 keV energy range. The others have been obtained for the following energy band 0.6-3.8 keV , 3.6-9 keV, 0.8-9 keV with better time resolution. Background lightcurves, in the energy band 0.8-9 keV with 30 sec resolution, are also available only for those observations in which half of the ME detector was on source, and the other half monitoring the background. The EXOSAT ME lightcurves in FITS format make use of the FITS binary table extension (BINTABLE). The specific FITS layout of the data is described in the Legacy 3, 32. The total number of EXOSAT lightcurves is 19592, which includes the background and the four data sets of on-source lightcurves. HEASARC generated also two GIF files of the lightcurves (available from the EXOSAT me FTP area) for each observation. One is the plot of the broad band 0.8-9 keV data, the other show the lightcurves in the low (0.8-3.6 keV) and high (3.6-9 keV) energy band.

• Spectra and Response Matrices For each observing interval there is a background subtracted on-source spectrum integrated over the entire observing interval. If alternatively both halfs of the ME array were on-source during an observation, the average spectrum was corrected for the difference due to the background spectrum and counting rate between the two halfs by using standard "difference spectra". The EXOSAT ME spectra and response matrices in FITS format make use of the FITS binary tavble extension (BINTABLE).The specific FITS layout for spectra and response matrices are described in the Legacy 2, 65 and Legacy 2, 51 respectivaly. The total number of EXOSAT spectra and response matrices is 4602. HEASARC generated also GIF files of the spectra which show the spectrum convolved for the response matrix.

Products naming convention The ME product file names are a 6-character strings, a letter followed by a 5-digit number, generated automatically by the computer, based on the start time of the observation. The first character, which identifies the product type, has a different convention for the 3 experiments (LE+CMA, ME and GS), but within an experiment different products associated with the same observation share the 5 digit number. The ME 30-sec lightcurves have `d' as first character, and the multi-band lightcurves use `a' (lower energy),'b' (higher energy), and 'c' (total band). The background lightcurves have `r' as a suffix and the spectra use `s.'

Software

• Products: XSPEC and XRONOS software packages are useful for analysis of the FITS spectra and lightcurves respectivaly. The FTOOLS package provides also a number of programs to manipulate the FITS file. The GIF files can be viewed on UNIX and VMS with the package xv, under DOS with ColorView and under MacOS with Giffer.