Early In-orbit Performance of Scanning Sky Monitor Onboard AstroSat


We report the in-orbit performance of Scanning Sky Monitor (SSM) onboard AstroSat. The SSM operates in the energy range 2.5 to 10 keV and scans the sky to detect and locate transient X-ray sources. This information of any interesting phenomenon in the X-ray sky as observed by SSM is provided to the astronomical community for follow-up observations. Following the launch of AstroSat on 28th September, 2015, SSM was commissioned on October 12th, 2015. The first power ON of the instrument was with the standard X-ray source, Crab in the field-of-view. The first orbit data revealed the basic expected performance of one of the detectors of SSM, SSM1. Following this in the subsequent orbits, the other detectors were also powered ON to find them perform in good health. Quick checks of the data from the first few orbits revealed that the instrument performed with the expected angular resolution of 12’ \(\times \) 2.5\(^\circ \) and effective area in the energy range of interest. This paper discusses the instrument aspects along with few on-board results immediately after power ON.

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The SSM team would like to acknowledges Director, ISAC for the constant support for delivery of this payload followed by the successful launch of AstroSat. The team also acknowledges various entities including SMG, CSG and others at ISAC and also CMSE, VSSC, who have contributed in making of the payload and the successful completion of various processes and procedures towards delivery of the payload. The SSM team also acknowledges all the members of SAG and other groups at ISAC who have contributed to the development of this successful payload. They also thank all the members of the review committees at various stages for the support in making this payload a success.

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Correspondence to M. C. Ramadevi.

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Ramadevi, M.C., Ravishankar, B.T., Sitaramamurthy, N. et al. Early In-orbit Performance of Scanning Sky Monitor Onboard AstroSat. J Astrophys Astron 38, 32 (2017). https://doi.org/10.1007/s12036-017-9454-9

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  • X-ray sky monitor
  • 1D position sensitive proportional counter
  • coded mask
  • AstroSat
  • X-ray transients