Investigation of the stellar population and determination of interstellar extinction toward the Chandra Bulge Field based on RTT-150 data

Abstract

We have investigated the stellar population of the Chandra Bulge Field (CBF) 35′ × 35′ in area using the Russian-Turkish RTT-150 telescope with the goal of constructing an interstellar extinction map and determining the extinction law. The optical extinction has been determined from the positions of red clump giants (a group of red giants with the same luminosity and color) on the color-magnitude diagram in different parts of the field. This has allowed an interstellar extinction map of the field under consideration to be constructed with a resolution of 1′ × 1′. Based on the results of our analysis, we have also shown that the extinction law in the investigated field differs significantly from the standard one, most likely because the dust properties in the Galactic bulge differ from those in the Galactic disk. The derived extinction law confirms the measurements in the outer parts of the Galactic bulge.