Chandra Observations of MBM12 and Models of the Local Bubble

Chandra observations toward the nearby molecular cloud MBM12 show unexpectedly strong and nearly equal foreground O VIII and O VII emission. As the observed portion of MBM12 is optically thick at these energies, the emission lines must be formed nearby, coming either from the Local Bubble (LB) or ch...

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Bibliographic Details
Published in:arXiv.org 2005-01
Main Authors: Smith, R K, Edgar, R J, Plucinsky, P P, Wargelin, B J, Freeman, P E, Biller, B A
Format: Article
Language:English
Subjects:
Charge exchange
Emission
Molecular clouds
Solar system
Online Access:Get full text
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Summary:Chandra observations toward the nearby molecular cloud MBM12 show unexpectedly strong and nearly equal foreground O VIII and O VII emission. As the observed portion of MBM12 is optically thick at these energies, the emission lines must be formed nearby, coming either from the Local Bubble (LB) or charge exchange with ions from the Sun. Equilibrium models for the LB predict stronger O VII than O VIII, so these results suggest that the LB is far from equilibrium or a substantial portion of O VIII is from another source, such as charge exchange within the Solar system. Despite the likely contamination, we can combine our results with other EUV and X-ray observations to reject LB models which posit a cool recombining plasma as the source of LB X-rays.
ISSN:2331-8422
DOI:10.48550/arxiv.0501056