#AthenaNuggets: Observing Bright Sources with the Athena-WFI, by Jörn Wilms, Thomas Dauser & Arne Rau

In the #AthenaNuggets 17, Jörn Wilms, Thomas Dauser and Arne Rau explain that, since Athena’s instruments will have to cope X-ray binaries outbursts with rates above 100000 counts per second and nonlinear effects can distort measurements, it is mandatory to achieve readout frequencies that are significantly higher than the expected count rate. To observe brighter sources, the Wide Field Imager (WFI) will have a Fast Detector (FD) which is mounted beside the WFI Large Detector Array (LDA), keeping the desirable 1% pile-up limit. It is also mentioned in the Nugget, that an additional Be filter is currently under study which would remove photons below 2 keV without affecting the diagnostically important iron band.