Speaker: S. Elaheh Hosseini, Andreas Eckart (Cologne University, Max Planck Institute for Radio Astronomy)

Title: A new dense association of stars at the Galactic Center

Abstract: We focus on the 40 sources adjacent to the bow-shock source IRS1W, located at the distance of 6.05'' north-east from the supermassive black hole Sagittarius A*. We present the first proper-motion measurements of these sources which reveals we face a subgroup of co-moving stars. We detected these stars including IRS1W in H, K_s, L'. We confirm IRS 1W and its adjacent sources are forming a dense association of stars. We suggest they could be bound by an intermediate mass black hole (IMBH) or can be the result of a disk-like distribution projected close to the line of sight. We speculate about the existence of an IMBH or a disk explanation or the wind effect. Our measurements for the first time reveal that the dense association of stars including IRS1W is a co-moving group of stars at the distance of 6.05'' north-east from the supermassive black hole Sagittarius A*. The sources in this collection of stars have a similar proper motion and a common nature. This association of stars might be the remnant of a massive stellar cluster that has contained an intermediate mass black hole. The cluster exhibits features similar to IRS13N cluster. We present the proper motion of a group of co-moving stars in the region of IRS1W for the first time.