Study of three dimensional mapping of interstellar extinction in milky way galaxy

Abstract

The Ultraviolet Imaging Telescope (UVIT) is scheduled to be launched as a part of the ASTROSAT satellite. As part of the mission planning for the instrument we have studied the efficacy of UVIT observations for interstellar extinction measurements. We find that in the best case scenario, the UVIT can measure the reddening to an accuracy of about 0.02 magnitudes, which combined with the derived distances to the stars, will enable us to model the three-dimensional distribution of extinction in our Galaxy. The knowledge of the distribution of the ISM will then be used to study distant objects, affected by it. This work points the way to further refining the UVIT mission plan to best satisfy different science studies. newlineWe report here on our plans to use data from the Ultraviolet Imaging Telescope (UVIT) aboard the ASTROSAT mission to probe the extinction across the entire sky. This mission has been in develonment since 2000 (Agrawal 2001) and is expected to be launched on a Polar Satellite Launch Vehicle (PSLV) rocket by the Indian Space Research Organization (ISRO) in 2013. The UVIT instrument is being developed at the Indian Institute of Astrophysics (IIA) and includes three telescopes, two in the ultraviolet (FUV and NUV) and one in the visible, each including a filter wheel with a number of different filters (Kumar et al. 2012). We have run a series of simulations to determine which filters are best suited for our purpose and will use these results in planning our observations with the UVIT.