Complex small-scale structure in the infrared extinction towards the Galactic Centre

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.

5 pages, 3 figures, accepted for publication in ApJL

Cited by in corpus (6)

• The UKIDSS Galactic Plane Survey
• Tracing the long bar with red-clump giants
• The complex, variable near infrared extinction towards the Nuclear Bulge
• Interstellar Extinction and Long-Period Variables in the Galactic Center
• A Search for the Near-Infrared Counterpart to GCRT J1745-3009
• The Mid-Infrared Colors of the ISM and Extended Sources at the Galactic Center