NRAO/Socorro Colloquium Series
Thomas Dame
CfA
The Milky Way as a Grand Design Spiral
Although many grand design models of our Galaxy's spiral structure
have been proposed over the past fifty years, unambiguous evidence
for the type of two-fold symmetry expected of a barred spiral galaxy
such as ours has remained elusive. In the far side of the Galaxy,
spiral arms outside the solar circle are extremely distant and
relatively deficient in molecular gas, and those within are largely
masked by near-side material at the same velocity. A unique exception
in the inner Galaxy is our recent identification of the Far 3-kpc
Arm, its clear symmetry with respect to its near-side counterpart
apparent only because of the large outward motions of both arms. We
recently identified another far-side spiral arm in CO and H I, this
one in the outer Galaxy at a distance of ~21 kpc. This arm appears to
be the distant end of the prominent Scutum-Centaurus Arm and the
symmetric counterpart of the nearby Perseus Arm. The discovery of
both new arms will be described and discussed in the context of the
large-scale structure of the Milky Way.
March 30, 2012
11:00 am
Array Operations Center Auditorium
All NRAO employees are invited to attend via
video, available in Charlottesville Room 230, Green Bank Room 137 and
Tucson N525.
Local Host: Andres Brunthaler
