2011/04/15 by Patrick Kavanagh, P. J. Kavanagh, L. Norci +1
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Coma Cluster #Core (optical fiber) #Emission spectrum #Galaxy #Galaxy cluster #Optics #Physics #Population #RADIUS #Spectral line #Stellar, planetary, and galactic studies #Supernova #Thermal #astro-ph.HE
paper · pdf · doi:10.1016/j.newast.2011.04.001
published as New Astronomy 16 (2011), pp. 461-469
openalex publication_date 2011/04/15 · arxiv created 2011/06/14 · arxiv updated 2011/06/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present an analysis of the diffuse hard X-ray emission in the core of the young massive Galactic cluster Westerlund 1 based on a 48 ks XMM-Newton observation. Chandra results for the diffuse X-ray emission have indicated a soft thermal component together with a hard component that could be either thermal or non-thermal. We seek to resolve this ambiguity regarding the hard component exploiting the higher sensitivity of XMM-Newton to diffuse emission. Our new X-ray spectra from the central (2' radius) diffuse emission are found to exhibit He-like Fe 6.7 keV line emission, demonstrating that the hard emission in the cluster core is predominantly thermal in origin. Potential sources of this hard component are reviewed, namely an unresolved Pre-Main Sequence population, a thermalized cluster wind and Supernova Remnants interacting with stellar winds. We find that the thermalized cluster wind likely contributes the majority of the hard emission with some contribution from the Pre-Main Sequence population. It is unlikely that Supernova Remnants are contributing significantly to the Wd1 diffuse emission at the current epoch.