SOFIA Observes Signs of Starbursts in the Galactic Center 

The Stratospheric Observatory for Infrared Astronomy (SOFIA) captured
images of the Circumnuclear Ring (CNR) of gas and dust seven light-years in
diameter surrounding the supermassive black hole at the center of the Milky
Way, and of a neighboring cluster of extremely luminous young stars
embedded in dust cocoons. The images were taken with the FORCAST mid-IR
camera (P.I. Terry Herter, Cornell University) and released at the American
Astronomical Society's 221st meeting in Long Beach, California.

The mid-IR images reveal in detail the structure of the warm dust in the
CNR, a torus of material orbiting the supermassive black hole at the
Galactic center, as well as the prominent streamers of ionized gas and hot
dust within the CNR that compose the HII region Sgr A West. The emission at
19.7 microns from the dust in the CNR closely traces the ionized gas
emission as observed in the radio and near-IR, whereas the emission at 31.5
and 37.1 microns trace a cooler distribution of dust located at a slightly
greater radius in the CNR. This is consistent with the prevailing view that
the CNR material is heated and excited by the massive Central Cluster of
stars interior to the CNR. Ryan Lau of Cornell University is lead author of
the poster paper regarding SOFIA/FORCAST images of the CNR that was
presented at the Long Beach AAS meeting.

The Quintuplet Cluster (QC), located about 35 pc from the Central Cluster,
was also imaged by SOFIA/FORCAST. The QC contains the "Pistol Star", a blue
hypergiant that illuminates material of the Pistol Nebula ejected from the
star. Cool dust cocoons surrounding the most luminous members of the QC are
prominent at mid-IR wavelengths. The Central Cluster, the Quintuplet
Cluster, and the Arches Cluster in the Galactic center region have ages
between 6 and 1 million years, indicating a series of astronomically recent
star formation bursts. The Milky Way's center is much nearer than other
galaxies, making it easier to explore possible connections between the
starbursts and the black hole. Matt Hankins of the University of Central
Arkansas is lead author of the poster paper regarding the Quintuplet
Cluster that was presented at the AAS meeting.

The combination of FORCAST with SOFIA resulted in the highest angular
resolution ever obtained at these wavelengths, offering astronomers the
ability to resolve the Circumnuclear Ring and Quintuplet Cluster regions as
well as other exotic features in the Galactic center whose light is
obscured by water vapor in Earth's atmosphere.


More information about the SOFIA/FORCAST Galactic center observations, plus
links to download the images and the AAS poster papers, can be found at:

http://www.sofia.usra.edu/News/news_2013/01_08_13/index.html