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A Candidate Neutron Star Associated with Galactic Center Supernova Remnant Sagittarius A East

Sangwook Park·Michael P. Muno·Frederick K. Baganoff·Yoshitomo Maeda·Mark Morris·George Chartas·Divas Sanwal·David N. Burrows·Gordon P. Garmire
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Abstract

We present imaging and spectral studies of the supernova remnant (SNR) Sagittarius (Sgr) A East from deep observations with the {\it Chandra X-Ray Observatory}. The spatially-resolved spectral analysis of Sgr A East reveals the presence of a two-temperature thermal plasma ($kT$ $\sim$ 1 keV and 5 keV) near the center of the SNR. The central region is dominated by emission from highly-ionized Fe-rich ejecta. We estimate a conservative upper limit on the total Fe ejecta mass of the SNR, M$_{Fe}$ $<$ 0.27 M$_{\odot}$. Comparisons with standard SN nucleosynthesis models suggest that this Fe mass limit is consistent with a Type II SN explosion for the origin of Sgr A East. On the other hand, the soft X-ray emission extending toward the north of the SNR can be described by a single-temperature ($kT$ $\sim$ 1.3 keV) thermal plasma with normal chemical composition. This portion of the SNR is thus X-ray emission from the heated interstellar medium rather than the metal-rich stellar ejecta. We point out that a hard pointlike source CXOGC J174545.5$-$285829 (the so-called ``cannonball'') at the northern edge of the SNR shows unusual X-ray characteristics among other Galactic center sources. The morphological, spectral, and temporal characteristics of this source suggest an identification as a high-velocity neutron star. Based on the suggested Type II origin for the SNR Sgr A East and the proximity between the two, we propose that CXOGC J174545.5$-$285829 is a high-velocity neutron star candidate, born from the core-collapse SN which also created the SNR Sgr A East.

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Sangwook Park, Michael P. Muno, Frederick K. Baganoff, Yoshitomo Maeda, Mark Morris, George Chartas, Divas Sanwal, David N. Burrows, Gordon P. Garmire. 2005-06-08. A Candidate Neutron Star Associated with Galactic Center Supernova Remnant Sagittarius A East. https://doi.org/10.1086/432639

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