Katherine Blundell OBE

Abstract:

Chandra observations of 3C432, 3C 191 and B2 0902+34 are presented as part of an ongoing search for inverse-Compton scattering of the cosmic microwave background (CMB) from high redshift radio sources (Schwartz, 2000). The energy density of the CMB increases with redshift, z, as (1 + z)4, so the relatively high redshift of these powerful radio galaxies makes them good candidates for detecting extended inverse-Compton scattering along the radio jet axis: we do indeed detect radio-aligned X-ray emission.

Abstract:

A high level of complex structure, or ``granularity'', has been observed in the distribution of infrared-obscuring material towards the Galactic Centre (GC), with a characteristic scale of 5arcsec - 15arcsec, corresponding to 0.2 - 0.6pc at a GC distance of 8.5kpc. This structure has been observed in ISAAC images which have a resolution of 0.6arcsec, significantly higher than that of previous studies of the GC. We have discovered granularity throughout the GC survey region, which covers an area of 1.6deg x 0.8deg in longitude and latitude respectively (300pc x 120pc at 8.5kpc) centred on Sgr A*. This granularity is variable over the whole region, with some areas exhibiting highly structured extinction in one or more wavebands and other areas displaying no structure and a uniform stellar distribution in all wavebands. The granularity does not appear to correspond to longitude, latitude or radial distance from Sgr A*. We find that regions exhibiting high granularity are strongly associated with high stellar reddening.