| Abstract : | Wide-field satellites like AstroSat, Fermi, Neil Gehrels Swift Observatory, Integral, etc scour the skies for transients, making dozens of discoveries each month. Some of these instruments are designed to detect and report such transient events in near-real time, while others can take hours to days to report discoveries. In such cases, it is hard for a user to discern the cause of the absence of the report - has the search not been undertaken, was the source not detected, or was it simply not visible?
We introduce ASIMOV - Astronomical Satellites: Is My Object Visible - a publicly available web-based tool that addresses the third question. Given the location and time of a transient, ASIMOV uses the latest orbital elements of multiple space telescopes and checks the source visibility for each. The results page divides the instruments into three categories: ones which were passing through the South Atlantic Anomaly (SAA) and likely switched off, ones where the source was occulted by the Earth, and lastly satellites which may have detected the source. The tool does not account for the pointing direction and sensitive field of the satellite within the accessible sky. Furthermore, the tool generates useful skymaps to show the Earth-Occulted region for each satellite, as well as a map of Earth showing the positions of all satellites and the SAA. Such a tool can save valuable time in selecting what data sets should be analysed by a researcher interested in any particular transient. The tool is available on the website of the AstroSat Science Support Cell at http://astrosat-ssc.iucaa.in:8080/ASIMOV/ASIMOV.jsp . |
