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We present Classification of Cluster GAlaxy MEmbers (C$^2$-GaMe), a classification algorithm based on a suite of machine learning models that differentiates galaxies into orbiting, infalling, and background (interloper) populations, using…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-25 Daniel Farid , Han Aung , Daisuke Nagai , Arya Farahi , Eduardo Rozo

Context. Machine-Learning (ML) solves problems by learning patterns from data, with limited or no human guidance. In Astronomy, it is mainly applied to large observational datasets, e.g. for morphological galaxy classification. Aims. We…

Astrophysics of Galaxies · Physics 2016-04-27 Mario Pasquato , Chul Chung

Hubble Space Telescope ACS/WFC data in (B,I) are used to investigate the globular cluster populations around 6 gE galaxies ~40 Mpc distant. The total comprises a sample of ~8000 high-probability globular clusters. PSF-convolved King-model…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-25 William E. Harris

Luminosities and tidal radii of globular clusters have been used to estimate the perigalactic distances P of well-observed Galactic globulars that do not have collapsed cores. It is found that the cluster metallicity [Fe/H] correlates…

Astrophysics · Physics 2009-10-28 Sidney van den Bergh

Globular clusters (GCs) are powerful tracers of the galaxy assembly process, and have already been used to obtain a detailed picture of the progenitors of the Milky Way. Using the E-MOSAICS cosmological simulation of a (34.4 Mpc)$^3$ volume…

Only one globular cluster (GC), 47 Tuc, has been found to contain intracluster medium, with an electron density 100 times higher than that of the ISM in its vicinity. The characteristics of this intracluster medium are closely related to GC…

We establish a framework for determing absolute ages of Galactic globular clusters and then use these ages to investigate the age-metallicity and age-Galactocentric distance relations for the 36 clusters with the most reliable age data. The…

The formation of globular clusters (GC) with their multiple stellar populations remains a puzzling, unsolved problem in astrophysics. One way to gather critical insight consists in finding sizable numbers of GC progenitors (GCP) while still…

Astrophysics of Galaxies · Physics 2017-05-31 Alvio Renzini

Color-magnitude diagrams (CMDs) derived from Hubble Space Telescope (HST) Advanced Camera for Surveys F606W,F814W photometry of 6 globular clusters (GCs) are presented. The six GCs form two loose groupings in Galactocentric distance (Rgc):…

Astrophysics of Galaxies · Physics 2015-05-28 Aaron Dotter , Ata Sarajedini , Jay Anderson

Globular clusters (GCs) are the oldest stellar systems in the Milky Way. Long time considered as simple stellar populations, nowadays we recognize their complex star formation history through precise abundance analysis of a variety of…

Astrophysics of Galaxies · Physics 2015-06-05 Nikolay Kacharov , Andreas Koch

Clustering is the technique to partition data according to their characteristics. Data that are similar in nature belong to the same cluster [1]. There are two types of evaluation methods to evaluate clustering quality. One is an external…

Machine Learning · Computer Science 2024-09-05 Anupriya Vysala , Joseph Gomes

Nine presently known "young" Galactic globular clusters, which have ages / 3 Gyr smaller than the oldest clusters of similar metallicity, all have RGC > 15 kpc. Furthermore these young globulars are found to have below-average luminosities.…

Astrophysics · Physics 2009-10-30 Sidney van den Bergh

The formation histories of globular clusters (GCs) are a key diagnostic for understanding their relation to the evolution of the Universe through cosmic time. We use the suite of 25 cosmological zoom-in simulations of present-day Milky…

Astrophysics of Galaxies · Physics 2019-05-15 Marta Reina-Campos , J. M. Diederik Kruijssen , Joel L. Pfeffer , Nate Bastian , Robert A. Crain

We present a first analysis of the dynamics of in-situ globular clusters (GCs) in Milky Way (MW)-like galaxies embedded in fuzzy dark matter (FDM) halos, combining cosmological assembly histories from the TNG50 simulation with dedicated…

Astrophysics of Galaxies · Physics 2026-04-15 Pierre Boldrini , Paola Di Matteo

We use publicly available galaxy merger trees, obtained applying semi-analytic techniques to a large high resolution cosmological simulation, to study the environmental history of group and cluster galaxies. Our results highlight the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Gabriella De Lucia , Simone Weinmann , Bianca Poggianti , Alfonso Aragon-Salamanca , Dennis Zaritsky

Subjective classification of spiral galaxies is not sufficient for studying the effect of bars on their physical characteristics. In reality the problem is to comprehend the complex correlations in a multivariate parametric space.…

Astrophysics of Galaxies · Physics 2021-04-13 Prasenjit Banerjee , Tanuka Chattopadhyay , Asis Kumar Chattopadhyay

The location of a galaxy cluster's centroid is typically derived from observations of the galactic and/or gas component of the cluster, but these typically deviate from the true centre. This can produce bias when observations are combined…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-05 Z. Yan , N. Raza , L. Van Waerbeke , A. J. Mead , I. G. McCarthy , T. Troester , G. Hinshaw

Ages have been derived for 55 globular clusters (GCs) from overlays of isochrones onto the turnoff photometry, assuming distances based on fits of zero-age horizontal branch (ZAHB) models to the lower bound of the observed distributions of…

Astrophysics of Galaxies · Physics 2013-10-14 Don A. Vandenberg , Karsten Brogaard , Ryan Leaman , Luca Casagrande

The mass distribution and chemical composition of globular cluster (GC) systems preserve fossil record of the early stages of galaxy formation. The observed distribution of GC colors within massive early-type galaxies in the ACS Virgo…

Astrophysics of Galaxies · Physics 2015-06-19 Hui Li , Oleg Y. Gnedin

Linking globular clusters (GCs) to the assembly of their host galaxies is an overarching goal in GC studies. The inference of tight scaling relations between GC system properties and the mass of both the stellar and dark halo components of…

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