Readout Modes and Automated Operation of the Swift X-Ray Telescope
Abstract
The Swift X-ray Telescope (XRT) is designed to make astrometric, spectroscopic, and photometric observations of X-ray emission from Gamma-ray Bursts and their afterglows in the energy band 0.2-10 keV. In order to provide rapid-response, automated observations of these randomly occurring objects without ground intervention, the XRT must be able to observe objects covering some 7 orders of magnitude in flux, extracting the maximum possible science from each one. This requires a variety of readout modes designed to optimize the information collected in response to shifting scientific priorities as the flux from the burst diminishes.
The XRT will support three major readout modes: imaging, timing, and photon-counting, with several sub-modes. While all of these readout modes are based on readout techniques used on other missions, there are subtle but important differences. We describe in detail the readout modes of the XRT, and compare them with similar readout modes used on ASCA/SIS, Chandra/ACIS, and XMM/EPIC instruments. We describe the flux ranges over which each mode will operate, and the automated mode switching that will occur in the XRT. We also discuss the methods used for collection of bias information for this instrument.- Publication:
-
AAS/High Energy Astrophysics Division #7
- Pub Date:
- March 2003
- Bibcode:
- 2003HEAD....7.2225H