Extra-tidal star candidates in globular clusters of the sagittarius dwarf spheroidal galaxy
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2022-09
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Facultad/escuela
Idioma
en
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EDP Sciences
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Atribution 4.0 International (CC BY 4.0)
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https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
Context. Globular clusters (GCs) associated with the Sagittarius dwarf spheroidal galaxy (Sgr dSph) have evolved under the gravita tional potential of both Sgr dSph and the Milky Way. The effects of these potentials are most pronounced in the extra-tidal regions as
compared to the central regions of the GCs.
Aims. We aim to study the extra-tidal regions of the GCs that are possibly associated with Sgr dSph, namely Arp 2, Terzan 8,
NGC 5634, NGC 6284, Terzan 7, NGC 2419, NGC 4147, M 54 and Pal 12, using data from the Gaia early data release 3.
Methods. We selected the extra-tidal candidates based on their angular distances from the cluster centre in the RA-Dec plane, proper
motions of the clusters and the individual extra-tidal star candidates, and their positions on the colour-magnitude diagrams of the
clusters.
Results. We found extra-tidal candidates for the nine studied GCs. For eight of them, the surface density of candidate extra-tidal stars
in the vicinity of the clusters is in significant excess with respect to more distant surrounding fields. No extended extra-tidal features
beyond 5 tidal radii were detected for any of the clusters.
Conclusions. We publish a list of the most probable extra-tidal candidates that we determined using Gaia astrometric and photometric
data. Our analysis shows that the clusters that are associated with Sgr dSph are more likely affected by the gravitational potential of the
Sgr, as the distribution of extra-tidal stars is elongated in the same direction as the local stream. NGC 4147 is the only exception. We
found some high-probability candidate extra-tidal stars in several of the analysed clusters. We failed to detect any coherent large-scale
tidal tail around them
Notas
Indexación: Scopus.
Palabras clave
Globular Clusters: General, Galaxies: Clusters: individual: Sgr dSph, Galaxies: Dwarf, Galaxy: Formation, Galaxy: Stellar Content
Citación
Astronomy and AstrophysicsOpen. Volume 665. September 2022. Article number A8
DOI
DOI: 10.1051/0004-6361/202141912