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Globular clusters (GCs) are thought to be ancient relics from the early formative phase of galaxies, although their physical origin remains uncertain. GCs are most numerous around massive elliptical galaxies, where they can exhibit a broad…

Astrophysics of Galaxies · Physics 2020-10-13 Jeremy Lim , Emily Wong , Youichi Ohyama , Tom Broadhurst , Elinor Medezinski

We present a catalogue of low surface brightness (LSB) galaxies in the Coma cluster obtained from deep Subaru/Suprime-Cam V and R-band imaging data within a region of $\sim$4 deg$^2$. We increase the number of LSB galaxies presented in Yagi…

Astrophysics of Galaxies · Physics 2020-06-18 Adebusola B. Alabi , Aaron J. Romanowsky , Duncan A. Forbes , Jean P. Brodie , Nobuhiro Okabe

Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival of these Ultra Diffuse Galaxies (UDGs) in a rich cluster suggests that they have very high masses.…

Ultra-diffuse galaxies (UDGs) and compact dwarfs (CDs) occupy opposite extremes of the structural parameter space of dwarf galaxies, yet their spatial distributions in clusters suggest a possible evolutionary connection. Observational…

Astrophysics of Galaxies · Physics 2026-05-26 Nataša Pavlov , Ana Mitrašinović

The velocity dispersion of globular clusters (GCs) around ultra-diffuse galaxies (UDGs) in the Virgo cluster spans a wide range, including cases where GC kinematics suggest halos as massive as (or even more massive than) that of the Milky…

Using Jeans modelling, we calculate the velocity dispersion profile of the ultra-diffuse galaxy (UDG) Dragonfly 44 in MOND. For the nominal mass-to-light ratio from the literature and an isotropic profile, the agreement with the data is…

Astrophysics of Galaxies · Physics 2019-07-03 Michal Bílek , Oliver Müller , Benoit Famaey

Ultra-diffuse galaxies (UDGs) exhibit morphological similarities with other low-luminosity galaxies indicating a possible evolutionary connection. We investigate for common dynamical characteristics of isolated, HI-rich UDGs with other low…

Astrophysics of Galaxies · Physics 2025-01-22 Nilanjana Nandi , Arunima Banerjee , Ganesh Narayanan

Now almost 70 years since its introduction, the effective or half-light radius has become a very popular choice for characterising galaxy size. However, the effective radius measures the concentration of light within galaxies and thus does…

Astrophysics of Galaxies · Physics 2020-01-10 Nushkia Chamba , Ignacio Trujillo , Johan H. Knapen

We use the \textsc{Romulus25} cosmological simulation volume to identify the largest-ever simulated sample of {\it field} ultra-diffuse galaxies (UDGs). At $z=0$, we find that isolated UDGs have average star formation rates, colors, and…

Astrophysics of Galaxies · Physics 2021-01-20 Anna C. Wright , Michael Tremmel , Alyson M. Brooks , Ferah Munshi , Daisuke Nagai , Ray S. Sharma , Thomas R. Quinn

Unraveling the nature of dark matter (DM) stands as a primary objective in modern physics. Here we present evidence suggesting deviations from the collisionless Cold DM (CDM) paradigm. It arises from the radial distribution of stars in six…

Astrophysics of Galaxies · Physics 2024-07-25 Jorge Sanchez Almeida , Ignacio Trujillo , Angel R. Plastino

The large-scale distribution of globular clusters in the central region of the Coma cluster of galaxies is derived through the analysis of Hubble Space Telescope/Advanced Camera for Surveys data. Data from three different HST observing…

Astrophysics of Galaxies · Physics 2018-11-30 Juan P. Madrid , Conor R. O'Neill , Alexander T. Gagliano , Joshua R. Marvil

Clusters and groups of galaxies are highly aspherical, with shapes approximated by nearly prolate ellipsoids of revolution. An equally fundamental property is the shape of these objects in velocity space which is the anisotropy of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-30 Radoslaw Wojtak

A full understanding of how unusually large "Ultra Diffuse Galaxies" (UDGs) fit into our conventional understanding of dwarf galaxies remains elusive, despite the large number of objects identified locally. A natural extension of UDG…

We present a statistical analysis of the properties of a large sample of dynamically hot old stellar systems, from globular clusters to giant ellipticals, which was performed in order to investigate the origin of ultra-compact dwarf…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Tanuka Chattopadhyay , Margarita Sharina , Emmanuel Davoust , Tuli De , Asis Kumar Chattopadhyay

We present preliminary results of the search for Ultra-compact dwarf galaxies in the central region of the Antlia cluster. This new kind of stellar system has brightness, mass and size between those observed in globular clusters and…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-11 J. P. Caso , L. P. Bassino , A. V. Smith Castelli

We present a sample of 115 very low optical surface brightness, highly extended, HI-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently…

The disks of spiral galaxies are generally elliptical rather than circular. The distribution of ellipticities can be fit with a log-normal distribution. For a sample of 12,764 galaxies from the Sloan Digital Sky Survey Data Release 1 (SDSS…

Astrophysics · Physics 2009-11-10 Barbara S. Ryden

In an earlier paper, we determined the morphological types of galaxies in the Coma Cluster using data from the HST/ACS Coma Cluster treasury survey. We found that of the 132 members, 51 are non dwarfs and 81 are dwarfs. We define dwarfs to…

Astrophysics of Galaxies · Physics 2024-05-21 Nagamani Poloji , Priya Hasan , S. N. Hasan

In this first paper in a series we present a study of the global dust emission distribution in nearby edge-on spiral galaxies. Our sample consists of 16 angularly large and 13 less spatially resolved galaxies selected from the DustPedia…