A morphological Study of the Galactic Inner Bulge

K. S. Baliyan1, S. Ganesh1, U. C. Joshi1, I. S. Glass2, and M. Morris3,A. Omont4, M. Schultheis4, G. Simon5

1 Physical Research Laboratory, Ahmedabad, India
2 South African Astronomical Observatory, Observatory, South Africa
3 UCLA, USA
4 Institut d'Astrophysique de Paris, Paris, France
5 Observatoire de Paris, Paris, France

E-mail contact: baliyan@prl.ernet.in, shashi@prl.ernet.in

A sizable region of the Inner Galaxy was observed by the ISOGAL survey using ISOCAM imaging at 7 and 15um. The images from this survey display spectacular mid infrared emission and absorption features and highly crowded star fields. The regions surrounding the Galactic Center were observed with 3 arcsec resolution at 7 & 15 um narrow bands. However, to avoid damage to the detector due to saturation, Sgr A and nearby region was not observed.

In this poster we present these images and compare them with already known information at other wavelengths. The images exhibit a good correlation between locations of the dark clouds in mid-IR and emission at millimeter wavelengths. Examining the CO spectra in the direction of the dark patches seen in the ISOGAL images one can see that while most of these spots correspond to CO at relatively foreground velocities, there are also regions where the CO spectra indicate these patches of high extinction to be closer to the nuclear regions of the Galaxy. Among other extended emission features, the star forming regions, Sgr B1 and C, stand-out at mid-IR wavelengths with interesting correspondences with structures at 90cm seen in the images obtained by the VLA. Many 7 um sources appear aligned along the non-thermal filament associated with the Sgr C. The emission and absorption features seen in the images will be discussed in some detail.