SOFIA Highlights: Galactic center
By Matthew Hankins
Paper: SOFIA/FORCAST Galactic Center Legacy Survey: Overview
Hankins et al., 2020, ApJ.
SOFIA’s first completed legacy program provides researchers with a vastly improved view of warm dust in the center of the Galaxy, revealing signatures of star formation in exquisite detail.
By Kassandra Bell and Joan Schmelz
Supermassive black holes exist at the center of most galaxies, and our Milky Way is no exception. But many other galaxies have highly active black holes, meaning a lot of material is falling into them, emitting high-energy radiation in this “feeding” process. The Milky Way’s central black hole, on the other hand, is relatively quiet. New observations from NASA’s Stratospheric Observatory for Infrared Astronomy, SOFIA, are helping scientists understand the differences between active and quiet black holes.
Ryan Lau of Cornell University and his collaborators presented a poster paper analyzing SOFIA/FORCAST observations of mass loss from extremely luminous stars near the center of the Milky Way Galaxy during the 223rd meeting of the American Astronomical Society in Washington, DC.
SOFIA measurements of ionized carbon and nitrogen gas at the edge of the Central Molecular Zone (CMZ) of the Milky Way were made with the GREAT far-IR heterodyne spectrometer (P.I. Rolf Güsten, MPIfR) as a part of SOFIA’s Guest Investigator program. The observations were made over the course of several nights in July 2013 during SOFIA’s first Southern Hemisphere deployment.
The CMZ is a 400 pc x 80 pc region around the galactic center containing 10 million solar masses of giant molecular clouds, many regions of active star formation, and frequent supernova explosions.
SOFIA/FORCAST images of the H II (ionized hydrogen) complex G0.02-0.07 resolved a string of three compact HII regions (labeled A, B, and C in Figure 1) plus two new infrared sources designated FIRS 1 and 2 (Figures 1 and 2). G0.02-0.07 is located in the Sagittarius A (Sgr A) region, 6 pc (20 light years) from our line of sight to the center of the Milky Way Galaxy. The Galactic Center includes a hot, turbulent interstellar medium, cloud-cloud collisions, stellar winds, and supernova shocks.
Researchers using the Stratospheric Observatory for Infrared Astronomy (SOFIA) have captured new images of a ring 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.