One year of in-orbit operation of the AGILE Payload

AGILE, an Italian Space Agency (ASI) mission dedicated to the exploration of the gamma-ray Universe, was successfully launched on April 23, 2007 from the Indian base of Sriharikota in an low-particle background equatorial orbit at 550 km height. AGILE gamma ray range cover the 30 MeV – 50 GeV band with its detectors combined together in the Gamma-Ray Imaging Detector (GRID). An X-ray imager (SuperAGILE) operates in the 18 – 60 keV band. Some of the payload instruments are also operated to detect transient X and gamma events with the main target being the Gamma Ray Burst in the SuperAGILE band and above 300 keV. The GRID instrument consists of a Silicon-Tungsten Tracker, a Caesium Iodide Mini-Calorimeter (MCAL), and a plastic-scintillator Anticoincidence system (ACS). The GRID achieves an angular resolution of about 15’ for bright sources with an unprecedented large field-of-view about 2.5 sr with a time resolution of few microsec and a very reduced dead-time (less than 200 microsec for a gamma detection). The hard X-ray imager (SuperAGILE) combines a tungsten coded mask with Si detector with a technology identical to the Si-Tracker. It is on top of the gamma-ray detector and has an optimal angular resolution (about 6 arcmin) with good sensitivity over about 1 sr field of view (10–15 mCrab on axis for a 1-day integration). The burst monitoring combines the data from SuperAGILE and from MCAL which operates independently with a specific operative mode from 300 keV up to several tens of MeV. All the detector operations are mastered by the Payload Data Handling Unit (PDHU) that includes several operation for data selection and background rejection. AGILE has very innovative scientific payload for what concern both its detectors and its operative mode. After more than one year of in orbit operation the in-flight performances of the instruments as well as the operation of the background reducing algorithm are presented and the main scientific results achieved are discussed.