The structure of the Galactic bar

Abstract

We present a deep near-infrared wide-angle photometric analysis of the structure of the inner Galactic bar and central disk. The presence of a triaxial structure at the centre of the Galaxy is confirmed, consistent with a bar inclined at 22+/-5.5 deg from the Sun-Galactic centre line, extending to about 2.5 kpc from the Galactic centre and with a rather small axis ratio. A feature at l=-9.8 deg not aligned with this triaxiality suggests the existence of a second structure in the inner Galaxy, a double triaxiality or an inner ring. We argue that this is likely to be the signature of the end of the Galactic bar, at about 2.5-3 kpc, which is circumscribed by an inner pseudo-ring. No thick dust lane preceding the bar is detected, and a hole in the disc's dust distribution inside the bar radius is inferred.