A COLLISIONAL ORIGIN FOR THE LEO RING
- Centre de Recherche Astrophysique de Lyon, Universite de Lyon, Universite Lyon 1, Observatoire de Lyon, Ecole Normale Superieure de Lyon, CNRS, UMR 5574, 9 avenue Charles Andre, 69561 Saint-Genis-Laval cedex (France)
- Laboratoire AIM, CEA/Irfu, CNRS, Universite Paris Diderot, SAp, 91191 Gif-sur-Yvette cedex (France)
- Canada-France-Hawaii Telescope, P.O. Box 1597, Kamuela, HI 96743 (United States)
- ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo (Netherlands)
- Observatoire Astronomique de Strasbourg (UMR7550), 11, rue de l'Universite, 67000 Strasbourg (France)
Extended H I structures around galaxies are of prime importance for probing galaxy formation scenarios. The giant H I ring in the Leo group is one of the largest and most intriguing H I structures in the nearby universe. Whether it consists of primordial gas, as suggested by the apparent absence of any optical counterpart and the absence of an obvious physical connection to nearby galaxies, or of gas expelled from a galaxy in a collision is actively debated. We present deep wide field-of-view optical images of the ring region obtained with MegaCam on the CFHT. They reveal optical counterparts to several H I and UV condensations along the ring, in the g', r', and i' bands, which likely correspond to stellar associations formed within the gaseous ring. Analyzing the spectral energy distribution of one of these star-forming regions, we found it to be typical for a star-forming region in pre-enriched tidal debris. We then use simulations to test the hypothesis that the Leo ring results from a head-on collision between Leo group members NGC 3384 and M96. According to our model which is able to explain, at least qualitatively, the main observational properties of the system, the Leo ring is consistent with being a collisional ring. It is thus likely another example of extended intergalactic gas made-up of pre-enriched collisional debris.
- OSTI ID:
- 21451036
- Journal Information:
- Astrophysical Journal Letters, Vol. 717, Issue 2; Other Information: DOI: 10.1088/2041-8205/717/2/L143; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
Intergalactic H I cloud in Leo: A simple modeling of the Spitzer-Baade collision event
THE TIP OF THE RED GIANT BRANCH DISTANCES TO TYPE Ia SUPERNOVA HOST GALAXIES. II. M66 AND M96 IN THE LEO I GROUP