Chandra Observation of the X‐Ray Source Population of NGC 6946

Abstract

We present the results of a study of discrete X-raysources in NGC 6946 using a deep Chandra ACIS observation. Based on theslope of the logN-logS distribution and the general correlation ofsources with the spiral arms, we infer that the overall discretesource sample in NGC 6946 is dominated by high-mass X-ray binaries,in contrast to the source distributions in M31 and the Milky Way.This is consistent with the higher star formation rate in NGC 6946than in those galaxies. We find that the strong X-ray sources inthe region of the galactic center do not correlate in detail withimages of the region in the near-IR, although one of them may becoincident with the galactic center. The noncentral ultraluminousX-ray source in NGC 6946, previously identified with a supernovaremnant, has an X-ray spectrum and luminosity that is inconsistent witheither a traditional pulsar wind nebula or a blast wave remnant.