The  Array  of  Low  Energy  X-ray  Imaging  Sensors  (ALEXIS)  

Satellite ________________________________________________________________     


   EAG is presently collaborating with the Los Alamos National Laboratory to accomplish an all sky survey at soft X-ray - EUV wavelengths of 133Å, 172Å and 188Å using a small satellite called ALEXIS. The ALEXIS satellite has three pairs of multilayer mirror telescopes with prime focus imaging detectors using highly curved microchannel plates and a wedge and strip nodes, developed by EAG. The astrophysical objectives of ALEXIS are: to map the diffuse galactic background with high angular resolution in several emission line bands, perform a 3-color soft X-ray survey of point sources, provide synoptic monitoring of variable ultrasoft X-ray sources such as cataclysmic variables and flare stars, and search for transient phenomena in the ultrasoft X-ray band. The six EAG-built detectors have been in almost constant operation over the past 36 months without failure.

   EAG at UC Berkeley has an ALEXIS satellite support facillity. In 1994, the ALEXIS science support facility at UC Berkeley came on-line. Its purpose is to process the ALEXIS  satellite astrophysical data, provide an ALEXIS  database, and support the needs of the guest investigators. A data pipeline has been developed to detect point sources in the ALEXIS data stream and to archive these in a form suitable for later analysis. EAG scientists Dr. Scott Cully and Dr. Rodriguez-Bell are currently working with guest investigators from Lawrence Livermore Laboratories and the Lockheed-Martin Group to carry out a research program to identify and characterize transient flare events in the soft X-ray sky.