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In L\"ovdal et al, we presented a data-driven method for clustering in Integrals of Motion space and applied it to a large sample of nearby halo stars with 6D phase-space information. We identified a large number of clusters, many of which…

Astrophysics of Galaxies · Physics 2022-09-14 Tomás Ruiz-Lara , Tadafumi Matsuno , S. Sofie Lövdal , Amina Helmi , Emma Dodd , Helmer H. Koppelman

We revisit the determination of the age of the Universe from galactic globular clusters, extending previous analyses by explicitly accounting for the presence of multiple stellar populations within each cluster. Using high--quality…

Astrophysics of Galaxies · Physics 2026-03-06 David Valcin , Raul Jimenez , Carmela Lardo , Uroš Seljak , Licia Verde

We present a set of 148 independent $N$-body simulations of globular clusters (GCs) computed using the code $\texttt{CMC}$ ($\texttt{Cluster Monte Carlo}$). At an age of $\sim10-13\,$Gyr, the resulting models cover nearly the full range of…

Globular clusters (GCs) display much lower binary fractions than found among main-sequence stars in the solar neighborhood. The physical cause of this difference is debatable: does it reflect different star formation outcomes at low…

Astrophysics of Galaxies · Physics 2026-04-06 Christopher E. O'Connor , Kyle Kremer , Frederic A. Rasio

We develop a simple analytic model for the gravitational clustering of dark haloes. The statistical properties of dark haloes are determined from the initial density field (assumed to be Gaussian) through an extension of the Press-Schechter…

Astrophysics · Physics 2007-05-23 H. J. Mo , S. D. M. White

We present new catalogs of likely globular clusters (GCs) in 17 nearby spiral galaxies studied as part of the PHANGS-HST Treasury Survey. The galaxies were imaged in five broad-band filters from the near-ultraviolet through the $I$ band.…

I present a simple phenomenological model for the observed linear scaling of the stellar mass in old globular clusters (GCs) with $z=0$ halo mass in which the stellar mass in GCs scales linearly with progenitor halo mass at $z=6$ above a…

Astrophysics of Galaxies · Physics 2017-09-26 Michael Boylan-Kolchin

We use a semi-analytic model for globular cluster (GC) formation built on dark matter merger trees to explore the relative role of formation physics and hierarchical assembly in determining the properties of GC populations. Many previous…

Astrophysics of Galaxies · Physics 2018-11-14 Kareem El-Badry , Eliot Quataert , Daniel R. Weisz , Nick Choksi , Michael Boylan-Kolchin

As a kind of basic machine learning method, clustering algorithms group data points into different categories based on their similarity or distribution. We present a clustering algorithm by finding hyper-planes to distinguish the data…

Computer Vision and Pattern Recognition · Computer Science 2020-04-28 Luhong Diao , Jinying Gao1 , Manman Deng

Machine learning is a powerful technique, becoming increasingly popular in astrophysics. In this paper, we apply machine learning to more than a thousand globular cluster (GC) models simulated as part of the 'MOCCA-Survey Database I'…

Astrophysics of Galaxies · Physics 2019-03-13 Ammar Askar , Abbas Askar , Mario Pasquato , Mirek Giersz

Because of their extreme stellar densities, globular clusters are highly efficient factories of X-ray binaries and radio pulsars: per unit of stellar mass, they contain about 1000 times more of these exotic objects. Thus far, 345 radio…

Star clusters have hierarchical patterns in space and time, suggesting formation processes in the densest regions of a turbulent interstellar medium. Clusters also have hierarchical substructure when they are young, which makes them all…

Astrophysics of Galaxies · Physics 2015-05-14 Bruce G. Elmegreen

We investigate the clustering and dark matter halo mass for a sample of $\sim$16,000 central galaxies selected from the SDSS/DR7 group catalog. We select subsamples of central galaxies on three two-dimensional planes, each formed by stellar…

Astrophysics of Galaxies · Physics 2016-03-16 Lixin Wang , Cheng Li , Y. P. Jing

Globular clusters (GCs) are sensitive tracers of galaxy assembly histories but interpreting the information they encode is challenging because mergers are thought to promote both the formation and disruption of GCs. We use simulations with…

The properties of old globular cluster systems in galaxy halos are used to infer quantitative constraints on aspects of generic star (cluster) formation. First, the spatial distribution of globulars in three large galaxies, together with…

Astrophysics · Physics 2007-05-23 Dean E. McLaughlin

The regularity/chaoticity of orbits of 45 globular clusters in the central region of the Galaxy with a radius of 3.5 kpc, which are subject to the greatest influence of the elongated rotating bar, is analyzed. Various methods of analysis…

Astrophysics of Galaxies · Physics 2025-12-16 A. T. Bajkova , A. A. Smirnov , V. V. Bobylev

We analyze the clustering of photometrically selected galaxy pairs by using the halo-occupation distribution (HOD) model. We measure the angular two-point auto-correlation function, $\omega(\theta)$, for galaxies and galaxy pairs in three…

Astrophysics of Galaxies · Physics 2015-06-22 Yiran Wang , R. J. Brunner

We present an analysis of the spatial distribution of globular cluster (GC) systems of 118 nearby early-type galaxies in the Next Generation Virgo Cluster Survey (NGVS) and Mass Assembly of early-Type GaLAxies with their fine Structures…

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

(Abridged): The total populations of globular cluster systems (GCSs) are discussed in terms of their connection to the efficiency of globular cluster formation---the mass fraction of star-forming gas that was able to form bound stellar…

Astrophysics · Physics 2009-10-31 Dean E. McLaughlin