On the Luminosity Functions of Giant Stars in Globular Clusters

1972 ◽  
Vol 177 ◽  
pp. 647 ◽  
Author(s):  
John N. Bahcall ◽  
Amos Yahil
Keyword(s):  
Globular Clusters ◽  
Giant Stars ◽  
Luminosity Functions

Luminosity Functions for Globular Clusters

1998 ◽  
Vol 509 (1) ◽  
pp. 192-202 ◽  
Author(s):  
Fabio Silvestri ◽  
Paolo Ventura ◽  
Francesca D'Antona ◽  
Italo Mazzitelli
Keyword(s):  
Globular Clusters ◽  
Luminosity Functions

scholarly journals The Formation and Evolution of LMC Globular Clusters: The Database

1999 ◽  
Vol 190 ◽  
pp. 460-461 ◽  
Author(s):  
S. F. Beaulieu ◽  
R. Elson ◽  
G. Gilmore ◽  
R. A. Johnson ◽  
N. Tanvir ◽  
...  
Keyword(s):  
Binary Stars ◽  
Globular Clusters ◽  
Star Clusters ◽  
Data Set ◽  
Luminosity Functions ◽  
Formation And Evolution ◽  
Mass Segregation ◽  
Large Cycle

We present details of the database from a large Cycle 7 HST project to study the formation and evolution of rich star clusters in the LMC (see Elson et al., this volume). Our data set, which includes NICMOS, WFPC2 and STIS images of 8 clusters, will enable us to derive deep luminosity functions for the clusters and to investigate the universality of the stellar IMF. We will look for age spreads in the youngest clusters, quantify the population of binary stars in the cores of the clusters and at the half-mass radii, and follow the development of mass segregation.

scholarly journals A Comparison Between the Relative Heavy Metal Abundance of the Extreme Halo Field Stars and Giant Stars of Globular Clusters

1978 ◽  
Vol 80 ◽  
pp. 169-172
Author(s):  
M. Spite ◽  
F. Spite
Keyword(s):  
Heavy Metal ◽  
Chemical Composition ◽  
Globular Clusters ◽  
Giant Stars ◽  
The Galaxy ◽  
Metal Abundance

Until very recently, estimates of the chemical composition at early epochs of the Galaxy were made through the analysis of halo field stars. Recently, however some medium dispersion studies of stars in globular clusters have appeared. It would be expected that both approaches would lead to identical results. However, a quick glance at the literature gives the opposite impression.

scholarly journals Constant light element abundances suggest that the extended P1 in NGC 2808 is not a consequence of CNO-cycle nucleosynthesis

2019 ◽  
Vol 485 (3) ◽  
pp. 4128-4133 ◽  
Author(s):  
I Cabrera-Ziri ◽  
C Lardo ◽  
A Mucciarelli
Keyword(s):  
Mass Fraction ◽  
Globular Clusters ◽  
Light Element ◽  
Complete Characterization ◽  
Alternative Mechanism ◽  
Abundance Pattern ◽  
Element Abundances ◽  
Chemical Enrichment ◽  
Giant Stars ◽  
Cno Cycle

Abstract Recent photometric results have identified a new population among globular cluster stars. This population, referred to as the ‘extended P1', has been suggested to be the manifestation of a new abundance pattern where the initial mass fraction of He changes among cluster stars that share the same CNO values. The current paradigm for the formation of the multiple stellar populations in globular clusters assumes that variations in He are the product of chemical ‘enrichment’ by the ashes of the CNO-cycle (which changes He and other elements like C, N and O simultaneously). We obtained MIKE@Magellan spectra of six giant stars in NGC 2808, a cluster with one of the strongest examples of the extended P1 population. We provide the first complete characterization of the light elements abundances for the stars along a significant range of the extended P1 photometric group. The stars from our sample appear to be homogeneous in C, N, O, Na, Mg and Al. The lack of a significant change in these products of the CNO-cycle suggests that unlike the rest of the populations identified to date, the photometric changes responsible for the extended P1 feature are a consequence of an alternative mechanism. Our measurements are consistent with the interpretations where the changes of the He mass fraction among these stars could be a consequence of p–p chain nucleosynthesis (which could increase the He in stars without affecting heavier elements). Having said that, direct measurements of He are necessary to conclude if variations of this element are present among extended P1 stars.

The range of UV upturn strengths in early-type galaxies can be caused by dissolved metal-rich Globular Clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 112-116
Author(s):  
Paul Goudfrooij
Keyword(s):  
Globular Clusters ◽  
Dynamical Evolution ◽  
Virgo Cluster ◽  
Host Galaxy ◽  
Early Type ◽  
Luminosity Functions ◽  
Central Regions ◽  
Specific Frequency ◽  
Uv Upturn

AbstractI summarize the scenario by Goudfrooij (2018) in which the bulk of the ultraviolet (UV) upturn of giant early-type galaxies (ETGs) is due to helium-rich stellar populations that formed in massive metal-rich globular clusters (GCs) and subsequently dissolved in the strong tidal field in the central regions of the massive host galaxy. These massive GCs are assumed to show UV upturns similar to those observed recently in M87, the central galaxy in the Virgo cluster of galaxies. Data taken from the literature reveals a strong correlation between the strength of the UV upturn and the specific frequency of metal-rich GCs in ETGs. Adopting a Schechter function parametrization of GC mass functions, simulations of long-term dynamical evolution of GC systems show that this correlation can be explained by variations in the characteristic truncation mass Mc such that Mc increases with ETG luminosity in a way that is consistent with observed GC luminosity functions in ETGs. These findings suggest that the nature of the UV upturn in ETGs and the variation of its strength among ETGs are causally related to that of helium-rich populations in massive GCs, rather than intrinsic properties of field stars in ETGs.

scholarly journals LUMINOSITY FUNCTIONS OF LMXBs IN CENTAURUS A: GLOBULAR CLUSTERS VERSUS THE FIELD

2009 ◽  
Vol 701 (1) ◽  
pp. 471-480 ◽  
Author(s):  
Rasmus Voss ◽  
Marat Gilfanov ◽  
Gregory R. Sivakoff ◽  
Ralph P. Kraft ◽  
Andrés Jordán ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Luminosity Functions ◽  
Centaurus A

scholarly journals Insights into the s-process and r-process as revealed by globular clusters

2009 ◽  
Vol 5 (S265) ◽  
pp. 54-56
Author(s):  
D. Yong ◽  
A. I. Karakas ◽  
D. L. Lambert ◽  
A. Chieffi ◽  
M. Limongi
Keyword(s):  
Relative Abundance ◽  
Neutron Capture ◽  
Globular Clusters ◽  
Giant Stars ◽  
The Mean ◽  
R Process ◽  
Process Material

AbstractWe present abundance measurements for a large number of neutron-capture elements in giant stars of the globular clusters M4, M5, and M13. The relative abundance ratios differ between all three clusters. For all clusters, we find that the mean abundances for the elements from Ba to Hf can be well explained by scaled versions of the solar s- and r-process abundances, albeit with different mixtures of s- and r-process material for each clusters.

scholarly journals Rubidium and Lead Abundances in Giant Stars of the Globular Clusters M4 and M5

2008 ◽  
Vol 673 (2) ◽  
pp. 854-863 ◽  
Author(s):  
David Yong ◽  
David L. Lambert ◽  
Diane B. Paulson ◽  
Bruce W. Carney
Keyword(s):  
Globular Clusters ◽  
Giant Stars
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