THE EXOSAT ME SLEW SURVEY

 

The sky coverage in the Medium Energy Slew Survey. This ranges from 0 seconds (black) to 600 seconds (white) and is displayed in galactic coordinates

The EXOSAT Medium Energy Slew provides a unique record of the 1-8 keV sky between 1983 and 1986. 98% of the sky was observed with 85% receiving an exposure of >60 seconds. 1210 sources were detected. By comparing positions with other catalogues, idientifications are given for 992 detections from 250 distinct objects, including 95 different X-ray binaries and 14 different AGN. More information can be found in Reynolds et al. 1999, Astronomy and Astrophysics, 134, 287.

To illustrate how the slew survey worked, here are three Lightcurves generated during EXOSAT slews by the ME instrument. The count rates increase as the detectors slew over a bright X-ray source. The count rates rise and fall in an approximately triangular fashion due to the response of the ME collimators.

The three lightcurves correspond to measurements made at the same time in the aligned array half (upper panel) and the two offset quadrants (middle and lower panels)

The known sources corresponding to the individual peaks are indicated.

Occasionally "new" sources such as EXO 0748-676, EXO 2030+375, EXO 1846-031 etc were discovered during slews before being followed-up with dedicated pointings. 

The "drop outs" in the lightcurves correspond to the short intervals between slew legs.

 

 

 
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