scholarly journals Kinematic complexity around NGC 419: resolving the proper motion of the cluster, the Small Magellanic Cloud, and the Magellanic bridge

2020 ◽  
Vol 500 (2) ◽  
pp. 2012-2019
Author(s):  
Davide Massari ◽  
Silvia Raso ◽  
Mattia Libralato ◽  
Andrea Bellini
Keyword(s):  
Proper Motion ◽  
Hubble Space Telescope ◽  
Tangential Direction ◽  
Magellanic Cloud ◽  
Stellar Clusters ◽  
Small Magellanic Cloud ◽  
Proper Motions ◽  
Kinematic Feature ◽  
First Time ◽  
Magellanic System

ABSTRACT We present Hubble Space Telescope proper motions in the direction of the star cluster NGC 419 in the Small Magellanic Cloud. Because of the high precision of our measurements, for the first time it is possible to resolve the complex kinematics of the stellar populations located in the field, even along the tangential direction. In fact, the proper motions we measured allow us to separate cluster stars, which move on average with ($\mu _{\alpha }\cos \delta ^{\rm NGC\, 419}, \mu _{\delta }^{\rm NGC\, 419}$) = (+0.878 ± 0.055, −1.246 ± 0.048) mas yr−1, from those of the Small Magellanic Cloud and those belonging to a third kinematic feature that we recognize as part of the Magellanic Bridge. Resolving such a kinematic complexity enables the construction of decontaminated colour–magnitude diagrams, as well as the measurement of the absolute proper motion of the three separate components. Our study therefore sets the first steps towards the possibility of dynamically investigating the Magellanic system by exploiting the resolved kinematics of its stellar clusters.

New Proper Motions of the Small Magellanic Cloud Using HST and Implications for Milky Way Mass

2017 ◽  
Vol 13 (S334) ◽  
pp. 394-395
Author(s):  
P. Zivick ◽  
N. Kallivayalil ◽  
S. Linden ◽  
T. Fritz ◽  
G. Besla ◽  
...  
Keyword(s):  
Milky Way ◽  
Hubble Space Telescope ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Wide Field ◽  
Small Magellanic Cloud ◽  
Proper Motions ◽  
Exact Mass ◽  
History Of ◽  
Magellanic Stream

AbstractAs new work on the proper motions (PMs) of the Large Magellanic Cloud (LMC) has come out, our view of the history of the Magellanic Clouds has evolved. We now believe they are on their first infall into the Milky Way (MW), having been tidally bound at the start of infall (though not necessarily now). Combining these observations with initial PMs of the Small Magellanic Cloud (SMC) suggests a new formation mechanism of the Magellanic Stream through the stripping of material from the SMC. However, large uncertainties remain in the exact mass of the LMC. We present a measurement of the systemic proper motions of the SMC from astrometry with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST), covering a ~3 year baseline of 30 fields with background QSOs. We find these motions to be μW = −0.82 ± 0.06 mas/yr and μN = −1.23 ± 0.07 mas/yr. Combining these measurements with previous efforts in studying the Clouds will help constrain their interactions with each other and the MW, including the mass of the LMC and the MW, as well as provide new insight into the internal dynamics of the SMC.

scholarly journals The Oldest Star Clusters in the Small Magellanic Cloud

1999 ◽  
Vol 190 ◽  
pp. 445-445 ◽  
Author(s):  
Kenneth J. Mighell ◽  
Ata Sarajedini ◽  
Rica S. French
Keyword(s):  
Star Formation ◽  
Theoretical Model ◽  
Observational Data ◽  
Hubble Space Telescope ◽  
Star Clusters ◽  
Magellanic Cloud ◽  
Wide Field ◽  
Small Magellanic Cloud ◽  
Formation Model ◽  
Age Sequence

We present our analysis of archival Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) observations in F450W (~B) and F555W (~V) of the intermediate-age populous star clusters NGC 121, NGC 339, NGC 361, NGC 416, and Kron 3 in the Small Magellanic Cloud. We use published photometry of two other SMC populous star clusters, Lindsay 1 and Lindsay 113, to investigate the age sequence of these seven star clusters in order to improve our understanding of the formation chronology of the SMC. We analyzed the V vs B–V and MV vs (B–V)o color-magnitude diagrams of these populous Small Magellanic Cloud star clusters using a variety of techniques and determined their ages, metallicities, and reddenings. These new data enable us to improve the age-metallicity relation of star clusters in the Small Magellanic Cloud. In particular, we find that a closed-box continuous star-formation model does not reproduce the age-metallicity relation adequately. However, a theoretical model punctuated by bursts of star formation is in better agreement with the observational data. The full details of this analysis are reported in Mighell, Sarajedini, & French (1998, AJ, 116, 2395).

scholarly journals The dynamics of an extremely young cluster probed for the first time

2009 ◽  
Vol 5 (S266) ◽  
pp. 386-389
Author(s):  
Christine Ducourant ◽  
Sylvain Bontemps ◽  
Didier Despois ◽  
Philippe André ◽  
Ramachrisna Teixeira ◽  
...  
Keyword(s):  
Velocity Field ◽  
Proper Motion ◽  
Velocity Dispersion ◽  
Open Cluster ◽  
Extended Period ◽  
Early Evolution ◽  
Proper Motions ◽  
Crucial Importance ◽  
Cluster Systems ◽  
First Time

AbstractWe present a proper-motion program that we have developed at ESO to measure, for the first time, proper motions of members of the nearby (125 pc), very young (4 × 105 yr) infrared ρ Ophiuchi cluster. Repeated imaging over an extended period will allow us to measure the global proper motion of the cluster and its velocity dispersion and will provide access to the ~ 1 km s−1 velocities for objects as faint as K = 15.7 mag. Access to the velocity field of such an extremely young cluster is of crucial importance to investigate the origin and early evolution of open cluster systems.

scholarly journals The VMC survey

2020 ◽  
Vol 641 ◽  
pp. A134
Author(s):  
Thomas Schmidt ◽  
Maria-Rosa L. Cioni ◽  
Florian Niederhofer ◽  
Kenji Bekki ◽  
Cameron P. M. Bell ◽  
...  
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
Dwarf Galaxies ◽  
Dynamical Evolution ◽  
Large Magellanic Cloud ◽  
Small Population ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Proper Motions ◽  
Flow Motion

Context. The Magellanic Clouds are a nearby pair of interacting dwarf galaxies and satellites of the Milky Way. Studying their kinematic properties is essential to understanding their origin and dynamical evolution. They have prominent tidal features and the kinematics of these features can give hints about the formation of tidal dwarfs, galaxy merging and the stripping of gas. In addition they are an example of dwarf galaxies that are in the process of merging with a massive galaxy. Aims. The goal of this study is to investigate the kinematics of the Magellanic Bridge, a tidal feature connecting the Magellanic Clouds, using stellar proper motions to understand their most recent interaction. Methods. We calculated proper motions based on multi-epoch Ks-band aperture photometry, which were obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA), spanning a time of 1−3 yr, and we compared them with Gaia Data Release 2 (DR2) proper motions. We tested two methods for removing Milky Way foreground stars using Gaia DR2 parallaxes in combination with VISTA photometry or using distances based on Bayesian inference. Results. We obtained proper motions for a total of 576 411 unique sources over an area of 23 deg2 covering the Magellanic Bridge including mainly Milky Way foreground stars, background galaxies, and a small population of possible Magellanic Bridge stars (< 15 000), which mostly consist of giant stars with 11.0 <  Ks <  19.5 mag. The first proper motion measurement of the Magellanic Bridge centre is 1.80 ± 0.25 mas yr−1 in right ascension and −0.72 ± 0.13 mas yr−1 in declination. The proper motion measurements of stars along the Magellanic Bridge from the VISTA survey of the Magellanic Cloud system (VMC) and Gaia DR2 data confirm a flow motion from the Small to the Large Magellanic Cloud. This flow can now be measured all across the entire length of the Magellanic Bridge. Conclusions. Our measurements indicate that the Magellanic Bridge is stretching. By converting the proper motions to tangential velocities, we obtain ∼110 km s−1 in the plane of the sky. Therefore it would take a star roughly 177 Myr to cross the Magellanic Bridge.

scholarly journals The Y dwarf population with HST: unlocking the secrets of our coolest neighbours – I. Overview and first astrometric results

2020 ◽  
Vol 501 (1) ◽  
pp. 911-915
Author(s):  
C Fontanive ◽  
L R Bedin ◽  
D C Bardalez Gagliuffi
Keyword(s):  
Proper Motion ◽  
Hubble Space Telescope ◽  
Proper Motions ◽  
Brown Dwarf ◽  
Space Telescope ◽  
First Results

ABSTRACT In this paper, we present our project that aims at determining accurate distances and proper motions for the Y brown dwarf population using the Hubble Space Telescope. We validate the program with our first results, using a single new epoch of observations of the Y0pec dwarf WISE J163940.83−684738.6. These new data allowed us to refine its proper motion and improve the accuracy of its parallax by a factor of three compared to previous determinations, now constrained to ϖ = 211.11 ± 0.56 mas. This newly derived absolute parallax corresponds to a distance of 4.737 ± 0.013 pc, an exquisite and unprecedented precision for faint ultracool Y dwarfs.

scholarly journals Correlation between mass segregation and structural concentration in relaxed stellar clusters

2019 ◽  
Vol 485 (4) ◽  
pp. 5752-5760 ◽  
Author(s):  
Ruggero de Vita ◽  
Michele Trenti ◽  
Morgan MacLeod
Keyword(s):  
Globular Clusters ◽  
Initial Conditions ◽  
Hubble Space Telescope ◽  
Stellar Clusters ◽  
Low Mass Stars ◽  
Best Fitting ◽  
Low Mass ◽  
The Difference ◽  
Mass Segregation ◽  
First Time

Abstract The level of mass segregation in the core of globular clusters has been previously proposed as a potential indicator of the dynamical constituents of the system, such as presence of a significant population of stellar-mass black holes (BHs), or even a central intermediate-mass black hole (IMBH). However, its measurement is limited to clusters with high-quality Hubble Space Telescope data. Thanks to a set of state-of-the-art direct N-body simulations with up to 200k particles inclusive of stellar evolution, primordial binaries, and varying BH/neutron stars, we highlight for the first time the existence of a clear and tight linear relation between the degree of mass segregation and the cluster structural concentration index. The latter is defined as the ratio of the radii containing 5 per cent and 50 per cent of the integrated light (R5/R50), making it robustly measurable without the need to individually resolve low-mass stars. Our simulations indicate that given R5/R50, the mass segregation Δm (defined as the difference in main-sequence median mass between centre and half-light radius) is expressed as Δm/M⊙ = −1.166R5/R50 + 0.3246, with a root-mean-square error of 0.0148. In addition, we can explain its physical origin and the values of the fitted parameters through basic analytical modelling. Such correlation is remarkably robust against a variety of initial conditions (including presence of primordial binaries and IMBHs) and cluster ages, with a slight dependence in best-fitting parameters on the prescriptions used to measure the quantities involved. Therefore, this study highlights the potential to develop a new observational tool to gain insight on the dynamical status of globular clusters and on its dark remnants.

scholarly journals The Proper Motion Field of the Small Magellanic Cloud: Kinematic Evidence for Its Tidal Disruption

2018 ◽  
Vol 864 (1) ◽  
pp. 55 ◽  
Author(s):  
Paul Zivick ◽  
Nitya Kallivayalil ◽  
Roeland P. van der Marel ◽  
Gurtina Besla ◽  
Sean T. Linden ◽  
...  
Keyword(s):  
Proper Motion ◽  
Magellanic Cloud ◽  
Motion Field ◽  
Small Magellanic Cloud ◽  
Tidal Disruption

scholarly journals N-Body Simulations of the Magellanic System Including Gas Dynamics and Star Formation

1999 ◽  
Vol 186 ◽  
pp. 60-60
Author(s):  
A.M. Yoshizawa ◽  
M. Noguchi
Keyword(s):  
Star Formation ◽  
Gas Dynamics ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud ◽  
Tidal Distortion ◽  
Formation And Evolution ◽  
Magellanic Stream ◽  
Magellanic System

The system of the Magellanic Clouds is considered to be dynamically interacting among themselves and with our Galaxy. This interaction is thought to be the cause of many complicated features seen in the Magellanic Clouds and the Magellanic Stream (see Westerlund 1990, A&AR, 2, 27). In order to better understand the formation and evolution of the Magellanic System, we carry out realistic N-body simulations of the tidal distortion of the Small Magellanic Cloud (SMC) due to our Galaxy and the Large Magellanic Cloud (LMC).

scholarly journals Proper Motions Of 47 TUC And NGC 362 Relative To The Small Magellanic Cloud

1988 ◽  
Vol 133 ◽  
pp. 465-468
Author(s):  
H.-J. Tucholke
Keyword(s):  
Globular Clusters ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Proper Motions ◽  
Stellar Proper Motions ◽  
Galactic Globular Clusters

The proper motions of the galactic globular clusters 47 Tuc and NGC 362 are currently being measured relative to the background of the Small Magellanic Cloud. This paper reports on the reduction routines developed so far for the simultaneous computation of several thousands of stellar proper motions. A preliminary result for NGC 362 is given.

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