C-19 and Hot, Wide, Star Streams
Abstract
The C-19 star stream has the abundance characteristics of an unusually metal poor globular cluster but kinematically is uncharacteristically hot and wide for a cluster stream, having a line of sight velocity dispersion of 7 +/- 2 km/s and a 1-sigma width of 240 pc. We show that the tidal dissolution of an old, lower mass, globular cluster in a CDM galactic halo can create a hot, wide stream currently near orbital apocenter. A cosmological Milky Way n-body simulation motivates the parameters for an evolving Milky Way halo potential containing an orbiting subhalo population in which we model a star cluster progenitor of C-19. The same model parameters have been used for a GD-1 stream model. The ~7 km/s velocity dispersion is readily accomplished with an evolving CDM subhalo population, a progenitor cluster mass ~2x10^4 M_sun and an orbit that keeps the progenitor orbital pericenter within about 10 kpc of the Milky Way dark halo or its precursors.
Cite
@article{arxiv.2410.22966,
title = {C-19 and Hot, Wide, Star Streams},
author = {Raymond G. Carlberg and Rodrigo Ibata and Nicolas F. Martin and Else Starkenburg and David S. Aguado and Khyati Malhan and Kim Venn and Kim Venn},
journal= {arXiv preprint arXiv:2410.22966},
year = {2025}
}
Comments
ApJ revised