Unraveling the mysteries of the Leo Ring: An absorption line study of an unusual gas cloud
- School of Physics, Astronomy, and Computational Science, George Mason University, Fairfax, VA 22030 (United States)
- Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States)
- Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)
Since the discovery of the large (2 × 10{sup 9} M{sub ☉}) intergalactic cloud known as the Leo Ring in the 1980s, the origin of this object has been the center of a lively debate. Determining the origin of this object is still important as we develop a deeper understanding of the accretion and feedback processes that shape galaxy evolution. We present Hubble Space Telescope/Cosmic Origins Spectrograph observations of three sightlines near the ring, two of which penetrate the high column density neutral hydrogen gas visible in 21 cm observations of the object. These observations provide the first direct measurement of the metallicity of the gas in the ring, an important clue to its origin. Our best estimate of the metallicity of the ring is ∼10% Z{sub ☉}, higher than expected for primordial gas but lower than expected from an interaction. We discuss possible modifications to the interaction and primordial gas scenarios that would be consistent with this metallicity measurement.
- OSTI ID:
- 22365571
- Journal Information:
- Astrophysical Journal, Vol. 790, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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