Proper motions in Terzan 5: membership of the multi-iron sub-populations and first constrain to the orbit

Abstract

By exploiting two sets of high-resolution images obtained with HST ACS/WFC over a baseline of ~10 years we have measured relative proper motions of ~70,000 stars in the stellar system Terzan 5. The results confirm the membership of the three sub-populations with different iron abudances discovered in the system. The orbit of the system has been derived from a first estimate of its absolute proper motion, obtained by using bulge stars as reference. The results of the integration of this orbit within an axisymmetric Galactic model exclude any external accretion origin for this cluster. Terzan 5 is known to have chemistry similar to the Galactic bulge; our findings support a kinematic link between the cluster and the bulge, further strengthening the possibility that Terzan 5 is the fossil remnant of one of the pristine clumps that originated the bulge.

25 pages, 14 figures, accepted for publication by ApJ

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Cited by in corpus (19)

• Proper motions and dynamics of the Milky Way globular cluster system from Gaia DR2
• The age of the young bulge-like population in the stellar system Terzan5: linking the Galactic bulge to the high-z Universe
• The Age and Structure of the Galactic Bulge from Mira Variables
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters - XV. The dynamical clock: reading cluster dynamical evolution from the segregation level of blue straggler stars
• The Accreted Nuclear Clusters of the Milky Way
• A new class of fossil fragments from the hierarchical assembly of the Galactic bulge
• A panchromatic view of the bulge globular cluster NGC 6569
• A new model for the multiple stellar populations within Terzan 5
• Astrometry with MCAO: HST-GeMS proper motions in the globular cluster NGC 6681
• Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569
• Proper motions and structural parameters of the Galactic globular cluster M71
• High-resolution extinction map in the direction of the strongly obscured bulge fossil fragment Liller 1
• Clues to the formation of Liller 1 from modeling its complex star formation history
• Are the globular clusters with significant internal [Fe/H] spreads all former dwarf galaxy nuclei?
• Modeling the chemical enrichment history of the Bulge Fossil Fragment Terzan 5
• Towards Realistic Modeling of the Astrometric Capabilities of MCAO Systems: Detecting an Intermediate Mass Black Hole with MAVIS
• On the manifest link between Terzan 5 and the Galactic bulge
• The bulge globular cluster Terzan 6 as seen from multi-conjugate adaptive optics and HST
• Star Cluster Ecology: Revisiting the Origin of Iron and Age Complex Clusters