A kinematic view of NGC 1261: structural parameters, internal dispersion, absolute proper motion and Blue Straggler Stars

Abstract

We constructed a Hubble Space Telescope (HST) astro-photometric catalog of the central region of the Galactic globular cluster NGC 1261. This catalog, complemented with Gaia DR2 data sampling the external regions, has been used to estimate the structural parameters of the system (i.e., core, half-mass, tidal radii and concentration) from its resolved star density profile. We computed high-precision proper motions thanks to multi-epoch HST data and derived the cluster velocity dispersion profile in the plane of the sky for the innermost region, finding that the system is isotropic. The combination with line-of-sight information collected from spectroscopy in the external regions provided us with the cluster velocity dispersion profile along the entire radial extension. We also measured the absolute proper motion of NGC 1261 using a few background galaxies as a reference. The radial distribution of the Blue Straggler Star population shows that the cluster is in a low/intermediate phase of dynamical evolution.

19 pages, 12 figures, 2 tables; accepted for publication in ApJ

References in corpus (23)

• The Gaia mission
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. I. Overview of the Project and Detection of Multiple Stellar Populations
• Dynamical age differences among coeval star clusters as revealed by blue stragglers
• Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. I. Sample Selection, Data Reduction and NGC 7078 Results
• Hubble Space Telescope proper motion (HSTPROMO) catalogs of Galactic globular clusters. II. Kinematic profiles and maps
• Discovery of Carbon/Oxygen depleted Blue Straggler Stars in 47 Tucanae: the chemical signature of a mass-transfer formation process
• The radial distribution of blue straggler stars and the nature of their progenitors
• Another Non-segregated Blue Straggler Population in a Globular Cluster: the Case of NGC 2419
• The surface density profile of NGC 6388: a good candidate for harboring an intermediate-mass black hole
• Investigating mass segregation process in globular clusters with Blue Straggler Stars: the impact of dark remnants
• A Panchromatic Study of the Globular Cluster NGC 1904. I: The Blue Straggler Population
• The Outer Envelopes of Globular Clusters. II. NGC 1851, NGC 5824 and NGC 1261
• Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. V. The rapid rotation of 47 Tuc traced and modeled in three dimensions
• The Blue Straggler Population of the Globular Cluster M5
• Kinematical fingerprints of star cluster early dynamical evolution
• A family picture: tracing the dynamical path of the structural properties of multiple populations in globular clusters
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XVIII. Proper-motion kinematics of multiple stellar populations in the core regions of NGC 6352
• The Blue Straggler Star Population in NGC 1261: Evidence for a Post-Core-Collapse Bounce State
• Star density profiles of six old star clusters in the Large Magellanic Cloud
• Proper motions and structural parameters of the Galactic globular cluster M71
• Discovery of a double Blue Straggler sequence in M15: new insight into the core-collapse process
• Spectral Energy Distribution of Blue Stragglers in the core of 47 Tucanae
• Blue Straggler Star Populations in Globular Clusters: II. Proper-Motion Cleaned HST Catalogs of BSSs in 38 Galactic GCs

Cited by in corpus (13)

• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XXIII. Proper-motion catalogs and internal kinematics
• A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes
• Ongoing hierarchical massive cluster assembly: the LISCA II structure in the Perseus complex
• Structure and Internal Kinematics of Nine Inner Milky Way Globular Clusters
• The Gaia-ESO Survey: an extremely Li-rich giant in the globular cluster NGC 1261
• Blue Stragglers as tracers of the dynamical state of two clusters in the Small Magellanic Cloud: NGC 339 and NGC 419
• Discovery of double BSS sequences in the old Galactic open cluster Berkeley 17
• Intrinsic Metallicity Variation in the Intermediate Mass Type II Globular Cluster NGC 1261
• A young white dwarf orbiting PSR J1835-3259B in the bulge globular cluster NGC 6652
• The structural properties of multiple populations in the dynamically young globular cluster NGC 2419
• Towards Realistic Modeling of the Astrometric Capabilities of MCAO Systems: Detecting an Intermediate Mass Black Hole with MAVIS
• The ESO-VLT MIKiS survey reloaded: velocity dispersion profile and rotation curve of NGC 1904