Physics
Scientific paper
Jun 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997phdt........23s&link_type=abstract
Thesis (PHD). CORNELL UNIVERSITY , Source DAI-B 57/12, p. 7571, Jun 1997, 142 pages.
Physics
3
Sgr A*, Accretion Disk, Circumnuclear Disk, Siii, Silicon
Scientific paper
This thesis explores the mid-infrared properties of the Galactic Center from two sets of observations. The goal of the first project was to detect or set an upper limit on the mid-infrared flux from the non-thermal radio source and black hole candidate known as Sgr A*, which is located at the dynamical center of the Galaxy. Deep images of the central parsec of the Galaxy with 0.7'' resolution were obtained at 8.7 μm and 11.6 μm. Analysis of these images reveals for the first time a mid-infrared source coincident with Sgr A* to within the diffraction limit. This detection was difficult due to the poor contrast between the source and the strong background diffuse emission. A detection at each wavelength was established after employing deconvolution techniques. The derived fluxes are too bright and the spectrum is too red to be consistent with current dustless accretion disk models. The mid-infrared emission is best explained by the presence of warm dust which may be associated with an accretion disk at Sgr A* or heated by local stellar sources. The second set of observations is a study of the distribution and kinematics of the atomic gas in the inner few parsecs of the Galaxy as traced by the forbidden (SiII) line at 34.8 μm. The integrated (SiII) emission peaks near Sgr A* and extends past the inner edge of the Circumnuclear Disk (CND), passing through a gap in the dense molecular material to the northwest. The (SiII) maps have a spatial resolution of 15'' and a spectral resolution of 50 km/s. The spectra, which are characterized by generally broad linewidths (>100 km/s), are kinematically consistent with the CND rotation to the southwest but not to the north. The northern extension may be experiencing shocks and is likely to be infalling along the Northern Arm. Observations of high and (SiII) / (OI) and (SiII) dust continuum ratios support the conjecture that turbulent motions and shocks in the inner few parsecs of the Galaxy are destroying dust grains, thus elevating the abundance of atomic silicon.
No associations
LandOfFree
Mid-Infrared Observations of the Galactic Center does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Mid-Infrared Observations of the Galactic Center, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mid-Infrared Observations of the Galactic Center will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1478609