scholarly journals Imprints of evolution on the internal kinematics of Globular Clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 544-548
Author(s):  
Laura L. Watkins ◽  
Roeland P. van der Marel ◽  
Andrea Bellini ◽  
Mattia Libralato ◽  
Jay Anderson
Keyword(s):  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Proper Motions ◽  
Transfer Energy ◽  
Space Telescope ◽  
Velocity Anisotropy ◽  
Energy Equipartition ◽  
Age Of The Universe ◽  
Set Up ◽  
The Universe

AbstractGlobular clusters are collisional systems, meaning that the stars inside them interact on timescales much shorter than the age of the Universe. These frequent interactions transfer energy between stars and set up observable trends that tell the story of a cluster’s evolution. This contribution focuses on what we can learn by studying velocity anisotropy and energy equipartition in globular clusters with Hubble Space Telescope proper motions.

Internal kinematics of multiple stellar populations in globular clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 324-328
Author(s):  
Mattia Libralato
Keyword(s):  
High Precision ◽  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Stellar Populations ◽  
Stellar Systems ◽  
Proper Motions ◽  
Space Telescope ◽  
Formation And Evolution ◽  
Galactic Globular Clusters ◽  
Shed Light

AbstractSpectroscopy and photometry have revealed existence, complexity and properties of the multiple stellar populations (mPOPs) hosted in Galactic globular clusters. However, the conundrum of the formation and evolution of mPOPs is far from being completely exploited: the available pieces of information seem not enough to shed light on these topics. Astrometry, and in particular high-precision proper motions, can provide us the sought-after answers about how mPOPs formed and have evolved in these ancient stellar systems. In the following, I present a brief overview of the observational results on the internal kinematics of the mPOPs in some GCs thanks to Hubble Space Telescope high-precision proper motions.

scholarly journals The Hubble Constant

2000 ◽  
Vol 17 (1) ◽  
pp. 45-47 ◽  
Author(s):  
Jeremy Mould
Keyword(s):  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Hubble Constant ◽  
Big Bang ◽  
Accelerating Universe ◽  
De Sitter ◽  
Age Of The Universe ◽  
Extragalactic Distance Scale ◽  
The Big Bang ◽  
The Universe

AbstractWith the completion of the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale, it is interesting to form the dimensionless quantity H0t0 by multiplying the Hubble Constant by the age of the Universe. In a matter dominated decelerating Universe with a density exceeding 0·26 of the critical value, H0t0 < 1; in an accelerating Universe with the same Ωm = 0·26, but dominated by vacuum energy with ΩV ≥ 1 – Ωm, H0t0 ≥ 1. If the first globular clusters formed 109 years after the Big Bang, then with 95% confidence H0t0 =1·0 ± 0·3. The classical Einstein–de Sitter cosmological model has H0t0 = ⅔.

scholarly journals The H0 Key Project: Cepheids in NGC925, M101 and M100

1995 ◽  
Vol 155 ◽  
pp. 258-259
Author(s):  
S. M. G. Hughes
Keyword(s):  
Standard Model ◽  
Hubble Space Telescope ◽  
Big Bang ◽  
Distance Scale ◽  
Space Telescope ◽  
The Standard Model ◽  
Age Of The Universe ◽  
Extragalactic Distance Scale ◽  
The Big Bang ◽  
The Universe

AbstractAs part of the Extragalactic Distance Scale Key Project, the Hubble Space Telescope has been used to identify Cepheids in M100, M101 and NGC925, and to measure distances derived from the Cepheid PL relation. For M100, the distance of 17.1 ± 1.8 Mpc has been used to infer a preliminary value for H0 of ~ 80 km/s/Mpc, which brings the age of the Universe derived from the standard model of the Big Bang into conflict with the ages of the oldest stars.

[ITAL]Hubble Space Telescope[/ITAL] Imaging of the Globular Clusters in the Fornax Cluster: Color and Luminosity Distributions

1999 ◽  
Vol 117 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Carl J. Grillmair ◽  
Duncan A. Forbes ◽  
Jean P. Brodie ◽  
Rebecca A. W. Elson
Keyword(s):  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Space Telescope ◽  
Fornax Cluster

scholarly journals Measuring proper motions of galactic dwarf galaxies with Hubble Space Telescope

2007 ◽  
Vol 3 (S248) ◽  
pp. 244-247 ◽  
Author(s):  
S. Piatek ◽  
C. Pryor
Keyword(s):  
Research Group ◽  
Dwarf Galaxies ◽  
Hubble Space Telescope ◽  
Proper Motions ◽  
Future Directions ◽  
Space Telescope ◽  
The Past ◽  
Scientific Justification ◽  
Satellite Galaxies ◽  
Using Data

AbstractOver the past several years, our research group has been measuring proper motions for nearby dwarf satellite galaxies using data taken with the Hubble Space Telescope. In order to measure proper motions with an expected size of several tens of milliarcseconds per century using a time baseline of 2-4 years, our work required that positions of stars and QSOs be measured to an accuracy of ~0.25 mas (~0.005 pixel). This contribution reviews the scientific justification of this work and our methodology. It concludes with a few general results and future directions.

scholarly journals Hubble Space Telescope Studies of the Dense Central Regions of Globular Clusters

1996 ◽  
Vol 174 ◽  
pp. 19-28
Author(s):  
Puragra Guhathakurta ◽  
Brian Yanny ◽  
Donald P. Schneider ◽  
John N. Bahcall
Keyword(s):  
Density Profile ◽  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Stellar Populations ◽  
Core Collapse ◽  
Red Giants ◽  
Space Telescope ◽  
Blue Straggler ◽  
Central Regions ◽  
Stellar Density

We present results from an ongoing program to probe the dense central parts of Galactic globular clusters using multicolor Hubble Space Telescope images (WF/PC-I and WFPC2). Our sample includes the dense clusters M15, 47 Tuc, M30, NGC 6624, M3 and M13. The two main goals of our program are to measure the shape of stellar density profile in clusters (the slope of the density cusp in post core collapse clusters, in particular) and to understand the nature of evolved stellar populations in very dense regions and their variation as a function of radius. The latter includes studies of blue straggler stars and of the central depletion of bright red giants. Our recent WFPC2 study of M15 is described in detail.

scholarly journals The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters – XVII. Public Catalogue Release

2018 ◽  
Vol 481 (3) ◽  
pp. 3382-3393 ◽  
Author(s):  
D Nardiello ◽  
M Libralato ◽  
G Piotto ◽  
J Anderson ◽  
A Bellini ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Space Telescope ◽  
Galactic Globular Clusters
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