Neutral Hydrogen Clouds in the M81/M82 Group

• Published in: arXiv.org
• Main Authors: Chynoweth, Katie M, Langston, Glen I, Yun, Min S, Lockman, Felix J, Rubin, K H R, Scoles, Sarah A
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 25.03.2008
• Subjects: Angular velocity; Galaxies; Hydrogen clouds; Milky Way Galaxy; Physics - Astrophysics of Galaxies; Physics - Cosmology and Nongalactic Astrophysics; Physics - Earth and Planetary Astrophysics; Physics - High Energy Astrophysical Phenomena; Physics - Instrumentation and Methods for Astrophysics; Physics - Solar and Stellar Astrophysics
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0803.3631

We have observed a 3 degree x 3 degree area centered on the M81/M82 group of galaxies using the Robert C. Byrd Green Bank Telescope (GBT) in a search for analogs to the High Velocity Clouds (HVCs) of neutral hydrogen found around our galaxy. The velocity range from -605 to -85 km/s and 25 to 1970 km/s was searched for HI clouds. Over the inner 2 degrees x 2 degrees the 7-sigma detection threshold was 9.6 x 10^5 M_sun. We detect 5 previously unknown HI clouds associated with the group, as well as numerous associated filamentary HI structures, all lying in the range -105 < V_helio < +280 km/s. From the small angular distance of the clouds to group members, and the small velocity difference between group members and clouds, we conclude that the clouds are most likely relics of ongoing interactions between galaxies in the group.