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ASCA Guest Observer Facility

Simultaneous ASCA, RXTE and BeppoSAX Observations of 3C 273

(ASCA GOF Calibration Memo [ASCA-CAL-00-06-02, v1.0 (06/07/00): T. Yaqoob & ASCATEAM])


This document describes the results of two multimission calibration campaigns on 3C 273 with simultaneous observations by ASCA, RXTE and BeppoSAX (in July 1996 and June 1998). A thorough comparison of the ASCA and BeppoSAX results have been dicussed in detail in a report by Grandi and Guainazzi. That report discusses both the soft and hard X-ray cross-calibrattion. All results from BeppoSAX which are quoted here in this ASCA/RXTE report have been taken from the Grandi and Guainazzi report with kind permission.

This report concerns the comparison of the PCA and ASCA SIS and GIS instruments. Since the PCA does not have a useful repsonse below 3 keV the comparison is necessarily restricted to the hard 3-10 keV X-ray band.


1. Bottom Line
2. Spectral Fits
3. Observation Log & Lightcurves
4. Data Analysis Details


Bottom Line

For those interested in only a summary and "bottom line" of the analysis, here it is. Full details are given on separate pages.

Power-law Slope: The ASCA and PCA slopes are in excellent agreement, within the (small) statistical errors. The BeppoSAXASCA but still in good agreement with both PCA and ASCA within the errors. The MECS slope from July 1996 is smaller than ASCA by ~0.06. BUT BeppoSAX was not truly simultaneous with ASCA and RXTE in the July 1996 campaign so the slope may have varied. In summary, the slope differences between ASCA/PCA/MECS are not worse than 0.06.

Flux: PCA is more than 20% higher than ASCA. BeppoSAX and ASCA agreement is better than 3%.

  • In the July 1996 campaign the 3-10 keV power-law slope for the PCA (1.65 +/- 0.01) is compatible with the ASCA SIS+GIS 4-instrument value (1.65 -0.02,+0.03).

  • In the June 1998 campaign the 3-10 keV power-law slope for the PCA (1.68 +/- 0.01) is just compatible with the ASCA SIS+GIS 4-instrument value (1.66 -0.03,+0.01).

  • In the July 1996 campaign the 4-instrument ASCA 1.5-10 keV slope is steeper than the corresponding BeppoSAX MECS value by about 0.06 but the SIS1 value is in good agreement. BUT, note that the July 1996 ASCA and BeppoSAX observations were not truly simulateous so the slope could have varied. In the June 1998 campaign the 4-instrument ASCA and SIS1 slopes are both in good agreement with the MECS slope in the 1.5-10 keV band and are compatible at the 90% confidence level.

  • The 4-10 keV fluxes from the PCA are 23% and 28% higher than those for ASCA in the July 1996 and June 1998 campaigns respectively. These values are obtained using 4-instrument ASCA averages but approximately the same discrepancy is present no matter which ASCA instrument is used.

  • The 4-10 keV fluxes from the 4-instrument ASCA average and the BeppoSAX MECS agree with each other to better than 3%.


    Next:
    Spectral Fits

    This file was last modified on Monday, 30-Jul-2001 18:17:24 EDT
    Curator: Michael Arida (SP Sys); arida@milkyway.gsfc.nasa.gov
    HEASARC Guest Observer Facility
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    This file was last modified on Monday, 30-Jul-2001 18:17:24 EDT

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