The globular cluster NGC7492 and the Sagittarius tidal stream: together but unmixed

Abstract

We have derived from VIMOS spectroscopy the radial velocities for a sample of 71 stars selected from CFHT/Megacam photometry around the Galactic globular cluster NGC7492. In the resulting velocity distribution, it is possible to distinguish two relevant non-Galactic kinematic components along the same line of sight: a group of stars at $⟨v_{\mathrm{r}}⟩\sim 125$km s${}^{-1}$ which is compatible with the velocity of the old leading arm of the Sagittarius tidal stream, and a larger number of objects at $⟨v_{\mathrm{r}}⟩\sim -110$km s${}^{-1}$ that might be identified as members of the trailing wrap of the same stream. The systemic velocity of NGC7492 set at $v_{\mathrm{r}}\sim -177$km s${}^{-1}$ differs significantly from that of both components, thus our results confirm that this cluster is not one of the globular clusters deposited by the Sagittarius dwarf spheroidal in the Galactic halo, even if it is immersed in the stream. A group of stars with $<v_{\mathrm{r}}>\sim -180$km s${}^{-1}$ might be comprised of cluster members along one of the tidal tails of NGC7492.

6 pages, 4 figures, accepted for publication in MNRAS

References in corpus (5)

• The Dartmouth Stellar Evolution Database
• A search for stellar tidal debris of defunct dwarf galaxies around globular clusters in the inner Galactic halo
• Chemical abundances of giant stars in NGC 5053 and NGC 5634, two globular clusters associated with the Sagittarius dwarf Spheroidal galaxy?
• The globular cluster AM 4: yet another young globular associated with the Sgr Dwarf Spheroidal galaxy?
• The discovery of tidal tails around the globular cluster NGC 7492 with Pan-STARRS1

Cited by in corpus (4)

• Purveyors of fine halos: Re-assessing globular cluster contributions to the Milky Way halo build-up with SDSS-IV
• Spherical models of star clusters with potential escapers
• Ultraviolet Imaging Telescope (UVIT) observation of the Galactic Globular Cluster NGC 7492
• A search for stellar structures around nine outer halo globular clusters in the Milky Way