2010ApJ...721.1333M -
Astrophys. J., 721, 1333-1339 (2010/October-1)
The Hercules satellite: a stellar stream in the Milky Way halo?
MARTIN N.F. and JIN S.
Abstract (from CDS):
We investigate the possibility that the recently discovered Hercules Milky Way (MW) satellite is in fact a stellar stream in formation, thereby explaining its very elongated shape with an axis ratio of 3:1. Under the assumption that Hercules is a stellar stream and that its stars are flowing along the orbit of its progenitor, we find an orbit that would have recently brought the system close enough to the MW to induce its disruption and transformation from a bound dwarf galaxy into a stellar stream. The application of simple analytical techniques to the tentative radial velocity gradient observed in the satellite provides tight constraints on the tangential velocity of the system (vt= -16+6–22 km/s in the Galactic standard of rest). Combined with its large receding velocity, the determined tangential velocity yields an orbit with a small pericentric distance (Rperi= 6+9–2 kpc). Tidal disruption is therefore a valid scenario for explaining the extreme shape of Hercules. The increase in the mean flattening of dwarf galaxies as one considers fainter systems could therefore be the impact of a few of these satellites not being bound stellar systems dominated by dark matter but, in fact, stellar streams in formation, shedding their stars in the MW's stellar halo.
Abstract Copyright:
∼
Journal keyword(s):
galaxies: dwarf - galaxies: interactions - galaxies: kinematics and dynamics - Local Group
Simbad objects:
8
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2010ApJ...721.1333M and select 'bookmark this link' or equivalent in the popup menu