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arXiv · 0807.4573

Discovery of a young massive stellar cluster near HESS J1813-178

Maria Messineo·Donald F. Figer·Ben Davies·R. Michael Rich·E. Valenti·R. P. Kudritzki
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Abstract

We present the serendipitous discovery of a young stellar cluster in the Galactic disk at l=12deg. Using Keck/NIRSPEC, we obtained high- and low-resolution spectroscopy of several stars in the cluster, and we identified one red supergiant and two blue supergiants. The radial velocity of the red supergiant provides a kinematic cluster distance of 4.7pm0.4 kpc, implying luminosities of the stars consistent with their spectral types. Together with the known Wolf-Rayet star located 2.4' from the cluster center, the presence of the red supergiant and the blue supergiants suggests a cluster age of 6-8 Myr, and an initial mass of 2000 Msun. Several stars in the cluster are coincident with X-ray sources, including the blue supergiants and the Wolf-Rayet star. This is indicative of a high binary fraction, and is reminiscent of the massive young cluster Westerlund 1. The cluster is coincident with two supernova remnants, SNR G12.72-0.0 and G12.82-0.02, and the highly magnetized pulsar associated with the TeV gamma-ray source HESS J1813-178. The mixture of spectral types suggests that the progenitors of these objects had initial masses of 20 - 30 Msun.

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Maria Messineo, Donald F. Figer, Ben Davies, R. Michael Rich, E. Valenti, R. P. Kudritzki. 2008-07-29. Discovery of a young massive stellar cluster near HESS J1813-178. https://doi.org/10.1086/591673

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