Discovery of tidal RR lyrae stars in the bulge globular cluster M62
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Fecha
2018-12
Profesor/a Guía
Facultad/escuela
Idioma
en
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Título del volumen
Editor
Institute of Physics Publishing
Nombre de Curso
Licencia CC
Atribution 4.0 International (CC BY 4.0)
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
The RR Lyrae (RRL) rich globular cluster M62 (NGC 6266) is one of the most massive globular clusters in the
Milky Way, located in the dense region of the Galactic bulge, where dynamical processes that affect the survival of
globular clusters are maximized. Using Gaia second data release data we have found clear evidence for an excess
of RRLs beyond the cluster tidal radius of M62, associated partly with stars stripped into the Galaxy field. This is
confirmed with new Visible and Infrared Survey Telescope for Astronomy Variables in the Via Lactea Extended
survey observations, which discard any differential reddening effect as the possible cause of the observed RRL
density excess. We also determined the orbit of M62 using accurate new measurements of its distance, radial
velocity, and proper motions, finding that its orbit is prograde with respect to the direction of the Galactic rotation.
Orbits are integrated in the non-axisymmetric galactic model GravPot16, which includes the perturbations due to
the central Galactic bar. M62 shows a particular orbital behavior, having a dynamical signature of the bar-bulge
region. The small extra-tidal RRLs extensions that are observed are roughly aligned toward the galactic center, and
the direction is almost perpendicular to the galactic plane, not with its motion along its orbit. This may be a clear
sign of bulge-crossing shocks during the last passage close of the cluster toward its perigalacticon. M62 would be
the first clear observed case of bulge shocking in the inner Galaxy acting on a globular cluster
Notas
Indexación: Scopus.
Palabras clave
Galaxy: Bulge, Galaxy: Evolution, Galaxy: Kinematics and Dynamics, Globular Clusters: General
Citación
Astrophysical Journal Letters Volume 869, Issue 110 December 2018 Article number L10
DOI
DOI: 10.3847/2041-8213/aaf1cd