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TOPIC: Young massive stellar cluster

Blobrana

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Posts: 131433

Date: Jun 15 06:54 2012

PSR J1813-1749	Permalink

Title: Spin-Down Measurement of PSR J1813-1749: The Energetic Pulsar Powering HESS J1813-178 Authors: J. P. Halpern, E. V. Gotthelf, F. Camilo Two new X-ray timing observations of the 44.7 ms pulsar in G12.82-0.02/HESS J1813-178 were obtained with Chandra and XMM-Newton to determine its precise spin-down rate. With a period derivative of dP/dt = 1.265E-13, PSR J1813-1749 is the third most energetic pulsar in the Galaxy, having spin-down luminosity dE/dt = 5.6E37 erg/s. Lack of pulsed detection in a deep radio search from the Green Bank Telescope, and in gamma-rays from Fermi, are reported. We reconsider the distance to PSR J1813-1749/G12.82-0.02 in view of its large X-ray measured column density, N(H) = 10.E22 cm^-2, which exceeds the visual extinction A(V) = 9.1 to a young stellar cluster at d = 4.8 kpc that has been associated with it. Although the distance may well be larger, existing data do not constrain it further. The small radiative output of PSR J1813-1749/G12.82-0.02 in all bands would not exceed its spin-down power at any distance in the Galactic disk. Read more (45kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jul 30 12:03 2008

Young massive stellar cluster	Permalink

Title: Discovery of a young massive stellar cluster near HESS J1813-178 Authors: Maria Messineo, Donald F. Figer, Ben Davies, R. Michael Rich, E. Valenti, R.P. Kudritzki (Version v2) 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 4.7±0.4 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 magnetised 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. Read more (474kb, PDF) __________________

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