scholarly journals The Hubble Space Telescope UV Legacy Survey of Galactic globular clusters – XIII. ACS/WFC parallel-field catalogues

2018 ◽  
Vol 476 (1) ◽  
pp. 271-299 ◽  
Author(s):  
M Simioni ◽  
L R Bedin ◽  
A Aparicio ◽  
G Piotto ◽  
A P Milone ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Space Telescope ◽  
Parallel Field ◽  
Galactic Globular Clusters

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

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 Simulations of HST Observations of Globular Clusters

1988 ◽  
Vol 126 ◽  
pp. 455-464
Author(s):  
John N. Bahcall ◽  
Donald P. Schneider
Keyword(s):  
Globular Clusters ◽  
Angular Resolution ◽  
Hubble Space Telescope ◽  
High Angular Resolution ◽  
Space Telescope ◽  
Science Institute ◽  
Galactic Globular Clusters ◽  
Space Telescope Science Institute

The high angular resolution of the Hubble Space Telescope will provide opportunities for many fundamental observations of globular clusters, most of which have been extensively discussed in the literature. We have therefore chosen to devote our time (and pages) to a presentation of what HST observations may reveal about some aspects of galactic globular clusters. To avoid infringing upon programs that others may propose, we have limited ourselves to simulations of observations that are part of our Guaranteed Time Observations. [The complete catalog of GTO observations has published by the Space Telescope Science Institute and is available upon request.]

scholarly journals The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters – XIX. A chemical tagging of the multiple stellar populations over the chromosome maps

2019 ◽  
Vol 487 (3) ◽  
pp. 3815-3844 ◽  
Author(s):  
A F Marino ◽  
A P Milone ◽  
A Renzini ◽  
F D’Antona ◽  
J Anderson ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Empirical Relation ◽  
Light Element ◽  
Stellar Populations ◽  
Type I ◽  
Type Ii ◽  
Chemical Abundances ◽  
Space Telescope ◽  
Galactic Globular Clusters

Abstract The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated GCs and their stellar populations. In previous papers of this series we have introduced a pseudo two-colour diagram, or ‘chromosome map’ (ChM) that maximizes the separation between the multiple populations. We have identified two main classes of GCs: Type I, including ∼83 per cent of the objects, and Type II clusters. Both classes host two main groups of stars, referred to in this series as first (1G) and second generation (2G). Type II clusters host more complex ChMs, exhibiting two or more parallel sequences of 1G and 2G stars. We exploit spectroscopic elemental abundances from the literature to assign the chemical composition to the distinct populations as identified on the ChMs of 29 GCs. We find that stars in different regions of the ChM have different compositions: 1G stars share the same light-element content as field stars, while 2G stars are enhanced in N and Na and depleted in O. Stars with enhanced Al, as well as stars with depleted Mg, populate the extreme regions of the ChM. We investigate the intriguing colour spread among 1G stars observed in many Type I GCs, and find no evidence for internal variations in light elements among these stars, whereas either a ∼0.1 dex iron spread or a variation in He among 1G stars remains to be verified. In the attempt of analysing the global properties of the multiple-population phenomenon, we have constructed a universal ChM, which highlights that, though very variegate, the phenomenon has some common pattern among all the analysed GCs. The universal ChM reveals a tight connection with Na abundances, for which we have provided an empirical relation. The additional ChM sequences observed in Type II GCs are enhanced in metallicity and, in some cases, s-process elements. Omega Centauri can be classified as an extreme Type II GC, with a ChM displaying three main extended ‘streams’, each with its own variations in chemical abundances. One of the most noticeable differences is found between the lower and upper streams, with the latter, associated with higher He, being also shifted towards higher Fe and lower Li abundances. We publicly release the ChMs.

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