AAS 203rd Meeting, January 2004
Session 105 Dwarf, Irregular, LUM IR and Starburst Galaxies
Oral, Wednesday, January 7, 2004, 2:00-3:30pm, Regency VII

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[105.04] A Statistical investigation of HI in the Magellanic Bridge

E. Muller (Arecibo Observatory, Arecibo, Puerto Rico), S. Stanimirovic, E. Rosolowsky (Radio Astronomy Lab, UC Berkeley CA.), L. Staveley-Smith (ATNF, CSIRO, N.S.W. Australia)

We present results from two statistical structural analyses of the nearby tidal HI Bridge in the Magellanic system. Analyses of the spatial power spectrum suggest that the Magellanic Bridge, historically considered to be a single coherent feature, may in fact be a projection of two kinematically and morphologically distinct structures, possibly representing two arms of the Small Magellanic Cloud (SMC). The more turbulent southern parts of the Bridge appear to show structure organised similarly to the adjacent SMC, while the northern regions are shown to be relatively deficient in a large scale power. The modifications to the spatial power index by velocity fluctuations and the turbulent component are also highly variant across these two regions, where the northern part is significantly more affected by slower velocity perturbations than is the southern part.

We also probe the rate of variation of the HI spectra throughout the Bridge, by measuring the Spectral Correlation over selected subsets. The Spectral correlation algorithm is shown to be more sensitive to low-power structural variations than is the Fourier transformations used for the spatial power spectrum, and the results from this analysis highlight a tendency for the spectra of bright parts of the HI in the Bridge to have a more persistent correlation along a direction towards the Large Magellanic Cloud (LMC) and SMC. We attbribute this arrangement of structure to the large-scale tidal processes active during the evolution of the Magellanic Bridge.

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.