Pieces of the puzzle: Ancient substructure in the Galactic disk

Details Pieces of the puzzle: Ancient substructure in the Galactic disk Pieces of the puzzle: Ancient substructure in the Galactic disk

2005-05-19

arxiv.org/abs/astro-ph/0505401v2

Mon.Not.Roy.Astron.Soc. 365 (2006) 1309-1323

Astronomy and Astrophysics

Astrophysics

18 pages, 21 figures, MNRAS in press. Accepted version with high-resolution figures available from http://www.astro.rug.nl/~

Scientific paper

10.1111/j.1365-2966.2005.09818.x

We search for signatures of past accretion events in the Milky Way in the recently published catalogue by Nordstrom et al.(2004), containing accurate spatial and kinematic information as well as metallicities for 13240 nearby stars. To optimize our strategy, we use numerical simulations to characterize the properties of the debris from disrupted satellites. We find that stars with a common progenitor should show distinct correlations between their orbital parameters; in particular, between the apocentre A and pericentre P, as well as their z-angular momentum (L_z). In the APL-space, such stars are expected to cluster around regions of roughly constant eccentricity. The APL space for the Nordstrom catalogue exhibits a wealth of substructure, much of which can be linked to dynamical perturbations induced by spiral arms and the Galactic bar. However, our analysis also reveals a statistically significant excess of stars on orbits of common (moderate) eccentricity, analogous to the pattern expected for merger debris. Besides being dynamically peculiar, the 274 stars in these substructures have very distinct metallicity and age distributions, providing further evidence of their extra-Galactic provenance. It is possible to identify among these stars, three coherent Groups with characteristic ages and metallicities, that, in all likelihood, correspond to the remains of disrupted satellites. [abridged]

Affiliated with

Also associated with

No associations

Rating

Pieces of the puzzle: Ancient substructure in the Galactic disk does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Pieces of the puzzle: Ancient substructure in the Galactic disk, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pieces of the puzzle: Ancient substructure in the Galactic disk will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-582489