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The stellar disks of many spiral galaxies are twice as large as generally thought. We use archival data from the Galaxy Evolution Explorer mission (GALEX) to quantify the statistical properties of young stellar clusters in the outer,…

Astrophysics · Physics 2008-11-26 Dennis Zaritsky , Daniel Christlein

In this paper we report on the discovery of 27 low-surface brightness galaxies, of which 12 are candidate ultra-diffuse galaxy (UDG) in the Hydra I cluster, based on deep observations taken as part of the VST Early-type Galaxy Survey…

The VEGAS imaging survey of the Hydra I cluster reveals an extended network of stellar filaments to the south-west of the spiral galaxy NGC3314A. Within these filaments, at a projected distance of ~40 kpc from the galaxy, we discover an…

It is clear that within the class of ultra-diffuse galaxies (UDGs) there is an extreme range in the richness of their associated globular cluster (GC) systems. Here, we report the structural properties of five UDGs in the Perseus cluster…

Context. Ultra-diffuse galaxies (UDGs) are an intriguing population of galaxies. Despite their dwarf-like stellar masses and low surface brightness, they have large half-light radii and exhibit a diverse range of globular cluster (GC)…

It has been shown that ultra-diffuse galaxies (UDGs) have higher specific frequencies of globular clusters on average than other dwarf galaxies with similar luminosities. The UDG NGC5846-UDG1 is among the most extreme examples of globular…

We explore populations of ultra-diffuse galaxies (UDGs) in isolated, satellite, and cluster environments using the Romulus25 and RomulusC simulations, including how the populations vary with UDG definition and viewing orientation. Using a…

Astrophysics of Galaxies · Physics 2023-09-27 Jordan D. Van Nest , F. Munshi , A. C. Wright , M. Tremmel , A. M. Brooks , D. Nagai , T. Quinn

We report the discovery of post-starburst ultra-diffuse galaxies (UDGs), identified through spectroscopic analysis with KCWI at the Keck II Telescope. Our analysis is based on a sample of 44 candidate UDGs selected from the Systematically…

Using recent dust continuum data, we generate the intrinsic ellipticity distribution of dense, starless molecular cloud cores. Under the hypothesis that the cores are all either oblate or prolate randomly-oriented spheroids, we show that a…

Astrophysics · Physics 2009-11-07 Charles L. Curry

We have discovered a new type of galaxy in the Fornax Cluster: ``ultra-compact'' dwarfs (UCDs). The UCDs are unresolved in ground-based imaging and have spectra typical of old stellar systems. Although the UCDs resemble overgrown globular…

We derive the stellar population parameters of 11 quiescent ultra-diffuse galaxies (UDGs) from Keck/KCWI data. We supplement these with 14 literature UDGs, creating the largest spectroscopic sample of UDGs to date (25). We find a strong…

We decipher intrinsic three-dimensional shape distributions of molecular clouds, cloud cores, Bok globules, and condensations using recently compiled catalogues of observed axis ratios for these objects mapped in carbon monoxide, ammonia,…

Astrophysics · Physics 2009-11-07 C. E. Jones , Shantanu Basu

This paper discusses the observed at rotation curves of galaxies in the context of noncommutative geometry. The energy density of such a geometry is diffused throughout a region due to the uncertainty encoded in the coordinate commutator.…

General Relativity and Quantum Cosmology · Physics 2016-11-25 F. Rahaman , Peter K. F. Kuhfittig , K. Chakraborty , A. A. Usmani , Saibal Ray

By modelling the axis ratio distribution of SDSS DR8 galaxies we find the intrinsic 3D shapes of spirals and ellipticals. We use morphological information from the Galaxy Zoo project and assume a non-parametric distribution intrinsic of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Silvio Rodríguez , Nelson D. Padilla

In the past years a wealth of observations allowed to unravel the structural properties of the Dark Matter Halos around spirals. First, their rotation curves follow an Universal profile (URC) that can be described in terms of an exponential…

Astrophysics · Physics 2016-08-30 Paolo Salucci

We present the discovery of an isolated compact group of galaxies that is extremely dense (median projected galaxy separation: 6.9 kpc), has a very low velocity dispersion ($\sigma_{\rm 2D}$ = 67 km s$^{-1}$), and where all observed members…

Astrophysics · Physics 2009-10-31 R. Weinberger , S. Temporin , F. Kerber

(Abridged) A variety of formation scenarios was proposed to explain the diversity of properties observed in bulges. Studying their intrinsic shape can help in constraining the dominant mechanism at the epochs of their assembly. The…

Astrophysics · Physics 2015-05-13 J. Mendez-Abreu , J. A. L. Aguerri , E. M. Corsini , E. Simonneau

The Milky Way's satellite galaxies and Globular Clusters (GCs) are known to exhibit an anisotropic spatial distribution. We examine in detail this anisotropy by the means of the inertia tensor. We estimate the statistical significance of…

Astrophysics of Galaxies · Physics 2018-08-29 N. R. Arakelyan , S. V. Pilipenko , N. I. Libeskind

Ultra-diffuse galaxies (UDGs) are attractive candidates to probe cosmological models and test theories of galaxy formation at low masses; however, they are difficult to detect because of their low surface brightness. In the Local Group a…

We have then searched for preferential orientations of faint galaxies in the Coma cluster (down I_Vega~-11.5). By applying a deconvolution method to deep u* and I band images of the Coma cluster, we were able to recover orientations down to…

Astrophysics · Physics 2009-11-13 C. Adami , R. Gavazzi , J. C. Cuillandre , F. Durret , O. Ilbert , A. Mazure , R. Pello , M. P. Ulmer