Approximate analytical description of the high latitude extinction

Abstract

The distribution of visual interstellar extinction A_V has been mapped in selected areas over the Northern sky, using available LAMOST DR5 and Gaia DR2/EDR3 data. A_V was modelled as a barometric function of galactic latitude and distance. The function parameters were then approximated by spherical harmonics. The resulting analytical tridimensional model of the interstellar extinction can be used to predict A_V values for stars with known parallaxes, as well as the total Galactic extinction in a given location in the sky.