First results from a large-scale proper motion study of the Galactic Centre

Abstract

Proper motion studies of stars in the centre of the Milky Way have been typically limited to the Arches and Quintuplet clusters and to the central parsec. Here, we present the first results of a large-scale proper motion study of stars within several tens of parsecs of Sagittarius A* based on our $0.2^{\prime \prime }$ angular resolution GALACTICNUCLEUS survey (epoch 2015) combined with NICMOS/HST data from the Paschen-$\alpha$ survey (epoch 2008). This study will be the first extensive proper motion study of the central $\sim 36^{\prime }\times 16^{\prime }$ of the Galaxy, which is not covered adequately by any of the existing astronomical surveys such as Gaia because of its extreme interstellar extinction ($A_V\gtrsim 30$ mag). Proper motions can help us to disentangle the different stellar populations along the line-of-sight and interpret their properties in combination with multi-wavelength photometry from GALACTICNUCLEUS and other sources. It also allows us to infer the dynamics and interrelationship between the different stellar components of the Galactic Centre (GC). In particular, we use proper motions to detect co-moving groups of stars which can trace low mass or partially dissolved young clusters in the GC that can hardly be discovered by any other means. Our pilot study in this work is on a field in the nuclear bulge associated by HII regions that show the presence of young stars. We detect the first group of co-moving stars coincident with an HII region. Using colour-magnitude diagrams, we infer that the co-moving stars are consistent with being the post-main sequence stars with ages of few Myrs. Simulations show that this group of stars is a real group that can indicate the existence of a dissolving or low to intermediate mass young cluster. A census of these undiscovered clusters will ultimately help us to constrain star formation at the GC in the past few ten Myrs.

arXiv commentAccepted for publication in A&A. 13 pages, 17 figures

References in corpus (44)

• Monitoring stellar orbits around the Massive Black Hole in the Galactic Center
• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
• A large stellar evolution database for population synthesis studies. II. Stellar models and isochrones for an alpha-enhanced metal distribution
• The Stellar Cusp Around the Supermassive Black Hole in the Galactic Center
• The Nuclear Bulge of the Galaxy. III. Large-Scale Physical Characteristics of Stars and Interstellar Matter
• Analysis of isoplanatic high resolution stellar fields by Starfinder code
• Stellar dynamics in the central arcsecond of our galaxy
• Massive Stars in the Quintuplet Cluster
• Massive Stars in the Arches Cluster
• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• The nuclear star cluster of the Milky Way: proper motions and mass
• Line derived infrared extinction towards the Galactic Center
• The structure of the nuclear stellar cluster of the Milky Way
• The most massive stars in the Arches cluster
• Surface Brightness Profile of the Milky Way's Nuclear Star Cluster
• An Extended Star Formation History for the Galactic Center from Hubble Space Telescope/NICMOS Observations
• Interstellar Extinction Law toward the Galactic Center II: V, J, H, and Ks Bands
• The star formation history of the Milky Way's Nuclear Star Cluster
• Really Cool Stars and the Star Formation History at the Galactic Center
• The lives and deaths of star clusters near the Galactic center
• Evidence for a Long-Standing Top-Heavy IMF in the Central Parsec of the Galaxy
• Simultaneous Multi-Wavelength Observations of Sgr A* during 2007 April 1-11
• Three classical Cepheid variable stars in the nuclear bulge of the Milky Way
• HST Paschen-alpha Survey of the Galactic Center: Data Reduction and Products
• The Unusual Initial Mass Function of the Arches Cluster
• Proper motions of the Arches cluster with Keck-LGS Adaptive Optics: the first kinematic mass measurement of the Arches
• The proper motion of the Arches cluster with Keck Laser-Guide Star Adaptive Optics
• The nuclear cluster of the Milky Way: Our primary testbed for the interaction of a dense star cluster with a massive black hole
• Investigating the Relativistic Motion of the Stars Near the Supermassive Black Hole in the Galactic Center
• GALACTICNUCLEUS: A high angular resolution $JH{K}_s$ imaging survey of the Galactic Centre. I. Methodology, performance, and near-infrared extinction towards the Galactic Centre
• HST/NICMOS Paschen-alpha Survey of the Galactic Center: Overview
• GALACTICNUCLEUS: A high-angular-resolution JHKs imaging survey of the Galactic centre II. First data release of the catalogue and the most detailed CMDs of the GC
• Chemodynamical Modelling of the Galactic Bulge and Bar
• Kinematic Detection of the Galactic Nuclear Disc
• Holographic Imaging of Crowded Fields: High Angular Resolution Imaging with Excellent Quality at Very Low Cost
• An updated stellar census of the Quintuplet cluster
• The orbital motion of the Quintuplet cluster - a common origin for the Arches and Quintuplet clusters?
• Variability of the near-infrared extinction curve towards the Galactic centre
• Circumstellar discs in Galactic centre clusters: Disc-bearing B-type stars in the Quintuplet and Arches clusters
• The Quintuplet Cluster: Extended Structure and Tidal Radius
• IRTF/TEXES Observations of the HII Regions H1 and H2 in the Galactic Centre

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