AAS 201st Meeting, January, 2003
Session 31. The Galactic Center and Its Environs
Oral, Monday, January 6, 2003, 2:00-3:30pm, 6AB

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[31.05] Deep Chandra Imaging of the Central 20 Parsecs of the Galaxy: X-ray Filaments and Extended Structures

M.R. Morris (UCLA), F.K. Baganoff (MIT), C.D. Howard (UCLA), Y. Maeda (ISAS), E. Bautz (MIT), M. Feigelson, N. Brandt, G. Chartas, G. Garmire, L. Townsley (PSU)

The Galactic center was observed for 0.5 Msec with the ACIS-I instrument on the Chandra X-Ray Observatory between 22 May 2002 and 04 June 2002, with the primary goal of measuring short-term temporal fluctuations from SgrA* (reported separately by Baganoff at this meeting). A wealth of detail was observed in the ubiquitous, extended emission and over 2000 point sources were detected in the 17'x17' field of view. Diffuse X-ray emission is extended all along the Galactic plane, supplemented by a strong extended source identified with Sgr A East (Maeda et al. 2002, ApJ 570, 671). In addition, a strong X-ray complex appears at L=0.013, B=-0.054, and has no known counterpart at other wavelengths. Perhaps the most suggestive structure is a pair of apparent bipolar X-ray lobes placed roughly symmetrically about Sgr A* at distances of ~8.5 pc. These lobes are oriented perpendicular to the Galactic plane, raising the possibility that they have resulted from collimated ejections from the vicinity of SgrA*. The spectra of these features will be discussed in the context of this interpretation. On smaller scales, a number of filamentary X-ray structures, some with radio counterparts, have been found within the extended emission structures. The alternative hypotheses that these be edge-on shocks or linear magnetic filaments akin to nonthermal radio filaments will be discussed. In addition to the X-ray filaments, some other known radio sources are found to have X-ray counterparts, but the overall X-ray/radio correlation is relatively weak. Finally, the spatial relationship between dense interstellar clouds and edges or discontinuities in the extended X-ray emission has been examined in order to decide whether these are absorption edges attributable to foreground absorption or whether they represent density-bounded edges to the hot, X-ray emitting gas distribution.

This work was supported by NASA, under grant GO2-3115B.

The author(s) of this abstract have provided an email address for comments about the abstract: morris@astro.ucla.edu

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