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We present a chemical composition analysis of 36 giant stars in mildly metal-poor globular cluster M5. In comparing the M5 results to those obtained in M4, a cluster previously considered to be a ``twin'' in age, metallicity and chemical…

We report our analysis of a Chandra X-ray observation of the rich globular cluster Terzan 5, in which we detect 50 sources to a limiting 1.0-6 keV X-ray luminosity of 3*10^{31} ergs/s within the half-mass radius of the cluster. Thirty-three…

Astrophysics · Physics 2008-11-26 C. O. Heinke , R. Wijnands , H. N. Cohn , P. M. Lugger , J. E. Grindlay , D. Pooley , W. H. G. Lewin

Globular clusters are large collections of old stars that are orbiting the core of a galaxy. Our Milky Way Galaxy has about 160 known clusters, with perhaps more to be discovered. We first accumulated the necessary parameters for 16…

High Energy Astrophysical Phenomena · Physics 2017-12-22 Hambeleleni Ndiyavala , Christo Venter , Petrus Paulus Kruger

Key information to understand the formation and evolution of disk galaxies are imprinted in the stellar populations of their bulges. This paper has the purpose to make available new measurements of the stellar population properties of the…

Astrophysics of Galaxies · Physics 2015-06-23 L. Morelli , A. Pizzella , E. M. Corsini , E. Dalla Bontà , L. Coccato , J. Méndez-Abreu , M. Parmiggiani

NGC 5986 is a poorly studied but relatively massive Galactic globular cluster that shares several physical and morphological characteristics with "iron-complex" clusters known to exhibit significant metallicity and heavy element…

Galactic nuclei often harbor a disproportionately large amount of star formation activity with respect to their surrounding disks. Not coincidentally, the density of molecular material in galactic nuclei is often also much greater than that…

Astrophysics · Physics 2007-05-23 Donald F. Figer , Mark Morris

A growing number of recent observations have revealed that the Galactic globular cluster (GC) omega Cen is not the only GC that shows abundance spread in heavy elements (e.g., Fe). In order to understand the origin of the Galactic GCs with…

Astrophysics of Galaxies · Physics 2015-06-03 Kenji Bekki

The characteristics of the stellar populations in the Galactic Bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly important in light of cosmological simulations, which predict that…

Globular cluster systems exhibit a bewildering variety of characteristics. No single scenario appears to be able to account for the wide range of specific globular cluster frequencies that are observed in galaxies of various types. The…

Astrophysics · Physics 2009-10-31 Sidney van den Bergh

In the context of a project aimed at characterizing the properties of the so-called Bulge Fossil Fragments (the fossil remnants of the bulge formation epoch), here we present the first determination of the metallicity distribution of Liller…

In the last decade star clusters have been found in the centers of spiral galaxies across all Hubble types. We here present a spectroscopic study of the exceptionally bright (10^6 - 10^8 Lsun) but compact (Re ~ 5 pc) nuclear star clusters…

Various past theoretical considerations and observational efforts suggest the presence of a population of stellar-mass black holes in the innermost parsec of the Galactic centre. In this Letter, we investigate the impact of these black…

Astrophysics of Galaxies · Physics 2025-03-21 Jaroslav Haas , Pavel Kroupa , Ladislav Šubr , Myank Singhal

We present a detailed elemental abundance study of 90 F and G dwarf, turn-off and subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages and abundances for 11…

Some of the most massive globular clusters of our Milky Way, such as for example omega-Centauri, show a mixture of stellar populations spanning a few Gyr in age and 1.5 dex in metallicities. In contrast, standard formation scenarios predict…

Astrophysics · Physics 2009-11-11 Mike Fellhauer , Pavel Kroupa , Wyn Evans

We report on the discovery of three new millisecond pulsars (namely J1748-2446aj, J1748-2446ak and J1748-2446al) in the inner regions of the dense stellar system Terzan 5. These pulsars have been discovered thanks to a method, alternative…

High Energy Astrophysical Phenomena · Physics 2018-03-28 M. Cadelano , S. M. Ransom , P. C. C. Freire , F. R. Ferraro , J. W. T. Hessels , B. Lanzoni , C. Pallanca , I. H. Stairs

Long-slit spectroscopic observations of line-strengths and kinematics made along the minor axes of four spiral bulges are reported. Comparisons are made between central line-strengths in spiral bulges and those in other morphological types.…

Astrophysics · Physics 2009-10-31 R. N. Proctor , A. E. Sansom

Recent wide-field photometric surveys (Lee et al.; Pancino et al.) have shown the existence of a previously unknown metal-rich ([Fe/H] -0.6) stellar population in the galactic globular cluster omega Centauri. The discovery of this new…

Astrophysics · Physics 2009-11-07 F. R. Ferraro , M. Bellazzini , E. Pancino

Diffuse X-ray emission has been detected from a few Galactic globular clusters (GCs), whereas its nature still remains largely unclear. The GC Terzan 5 was previously found to show a significant diffuse thermal X-ray excess from its field,…

High Energy Astrophysical Phenomena · Physics 2025-01-15 Jiaqi Zhao , Craig O. Heinke , Su Fu

We report results from numerical simulations of star formation in the early universe that focus on gas at very high densities and very low metallicities. We argue that the gas in the central regions of protogalactic halos will fragment as…

Astrophysics · Physics 2009-06-23 Paul C. Clark , Simon C. O. Glover , Ralf S. Klessen

We investigate pulsar timing residuals due to the coupling effect of the pulsar transverse acceleration and the R$\rm{\ddot{o}}$mer delay. The effect is relatively small and usually negligible. Only for pulsars in globular clusters, it is…

High Energy Astrophysical Phenomena · Physics 2022-01-05 Li-Chun Wang , Yi Xie
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