Odin observations of ammonia in the SgrA +50 km s super(-1) cloud and circumnuclear disk

• Published in: Astronomy and astrophysics (Berlin) Vol. 599
• Main Authors: Sandqvist, Aa, Hjalmarson, A, Frisk, U, Lundin, S, Nordh, L, Olberg, M, Olofsson, G
• Format: Journal Article
• Language: English
• Published: 01.03.2017
• Subjects: Absorption; Astronomy; Clouds; Disks; Emission; Galactic structure; Line of sight; Milky Way Galaxy
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201629954

Context. The Odin satellite is now into its sixteenth year of operation, much surpassing its design life of two years. One of the sources which Odin has observed in great detail is the Sgr A complex in the centre of the Milky Way. Aims. To study the presence of NH sub(3) in the Galactic centre and spiral arms. Methods. Recently, Odin has made complementary observations of the 572 GHz NH sub(3) line towards the SgrA +50 kms super(-1) cloud and circumnuclear disk (CND). Results. Significant NH sub(3) emission has been observed in both the +50 kms super(-1) cloud and the CND. Clear NH sub(3) absorption has also been detected in many of the spiral arm features along the line of sight from the Sun to the core of our Galaxy. Conclusions. The very large velocity width (80 kms super(-1)) of the NH sub(3) emission associated with the shock region in the southwestern part of the CND may suggest a formation/desorption scenario similar to that of gas-phase H sub(2) O in shocks/outflows.