The Integrated Spectra of Metal-Rich Galactic Globular Clusters: A Two-Parameter Family

We begin with Fig. 1, which somewhat aged though it may be still illustrates important aspects of the subject (Gascoigne 1971) (i)There is a clear division of cloud clusters into a blue and red group. The division corresponds to the mass around 2.51M⊙, at which core degeneracy first develops in stars approaching the giant branch. Such stars spend about three times as long on the giant branch and travel higher up it than the slightly heavier non-degenerate stars, and so dominate the colours of the clusters in which they occur.(ii)The red clusters are somewhat less luminous than the globular clusters in the galaxy. Freeman and Chun (1972) have shown from dynamic arguments that the cloud clusters are also less massive, by enough to keep the M/L ratios roughly the same as those in the galaxy.(iii)For a long time it has been taken that the blue clusters are young and the red clusters old. Thus the clouds present us with a truly two-parameter family of globular-like clusters, the parameters being of course age and abundance.

Download Full-text

Extending the Red Giant Branch versus Metallicity Calibration toward Metal-poor Systems: Near-Infrared Photometry of the Galactic Globular Clusters M56 and M15

The Astronomical Journal ◽

10.1086/301363 ◽

2000 ◽

Vol 119 (5) ◽

pp. 2274-2281 ◽

Cited By ~ 10

Author(s):

Valentin D. Ivanov ◽

Jordanka Borissova ◽

Almudena Alonso-Herrero ◽

Tatiana Russeva

Keyword(s):

Globular Clusters ◽

Near Infrared ◽

Infrared Photometry ◽

Galactic Globular Clusters ◽

Red Giant

Download Full-text

The holographic conformal manifold of 3d $$ \mathcal{N} $$ = 2 S-fold SCFTs

Journal of High Energy Physics ◽

10.1007/jhep07(2021)221 ◽

2021 ◽

Vol 2021 (7) ◽

Author(s):

Nikolay Bobev ◽

Friðrik Freyr Gautason ◽

Jesse van Muiden

Keyword(s):

String Theory ◽

Three Dimensional ◽

Parameter Family ◽

Global Symmetry ◽

Maximal Supergravity ◽

All Solutions ◽

Operator Spectrum ◽

Type Iib String Theory ◽

Two Parameter

Abstract We employ a non-compact gauging of four-dimensional maximal supergravity to construct a two-parameter family of AdS4 J-fold solutions preserving $$ \mathcal{N} $$ N = 2 supersymmetry. All solutions preserve $$ \mathfrak{u} $$ u (1) × $$ \mathfrak{u} $$ u (1) global symmetry and in special limits we recover the previously known $$ \mathfrak{su} $$ su (2) × $$ \mathfrak{u} $$ u (1) invariant $$ \mathcal{N} $$ N = 2 and $$ \mathfrak{su} $$ su (2) × $$ \mathfrak{su} $$ su (2) invariant $$ \mathcal{N} $$ N = 4 J-fold solutions. This family of AdS4 backgrounds can be uplifted to type IIB string theory and is holographically dual to the conformal manifold of a class of three-dimensional S-fold SCFTs obtained from the $$ \mathcal{N} $$ N = 4 T [U(N)] theory of Gaiotto-Witten. We find the spectrum of supergravity excitations of the AdS4 solutions and use it to study how the operator spectrum of the three-dimensional SCFT depends on the exactly marginal couplings.

Download Full-text