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A method is developed to evaluate the magnifications of the images of galaxies with lensing potentials stratified on similar concentric ellipses. A simple contour integral is provided which enables the sums of the magnifications of even…

Astrophysics · Physics 2009-11-07 N. W. Evans , C. Hunter

Whether the spiral structure of galaxies is trailing or leading has been a subject of debate. We present a new spin parity catalog of 146 spiral galaxies that lists the following three pieces of information: whether the spiral structure…

Astrophysics of Galaxies · Physics 2020-01-08 Masanori Iye , Kenichi Tadaki , Hideya Fukumoto

We present an optical and near-infrared survey of galaxies in nearby clusters aimed at determining fundamental quantities of galaxies, such as multivariate luminosity function and color distribution for each Hubble type. The main…

The generalized Gullstrand-Painleve geometry is investigated for expanding matter. Compared to other studies, we take into account an anisotropic stress tensor as the source of curvature with an equation of state resembling the MIT bag…

General Relativity and Quantum Cosmology · Physics 2025-07-01 Hristu Culetu

The current photometric datasets, that span decades, allow for studying long-term cycles on active stars. Complementary Ca H&K observations give information also on the cycles of normal solar-like stars, which have significantly smaller,…

Solar and Stellar Astrophysics · Physics 2015-11-20 Heidi Korhonen

The universe displays a three-dimensional pattern of hot and cold spots in the radiation remnant from the big bang. The global geometry of the universe can be revealed in the spatial distribution of these spots. In a topologically compact…

Astrophysics · Physics 2009-10-30 Janna Levin , Evan Scannapieco , Giancarlo de Gasperis , Joseph Silk , John D. Barrow

It is well-known that a metric space $(X, d)$ is complete iff the set $X$ is closed in every metric superspace of $(X, d)$. For a given pseudometric space $(Y, \rho)$, we describe the maximal class $\mathbf{CEC}(Y, \rho)$ of superspaces of…

General Topology · Mathematics 2022-06-06 Viktoriia Bilet , Oleksiy Dovgoshey

We carry out a systematic, topos-theoretically inspired, investigation of Wallman compactifications with a particular emphasis on their relations with Gelfand spectra and Stone-Cech compactifications. In addition to proving several specific…

Category Theory · Mathematics 2012-04-17 Olivia Caramello

We introduce reflection properties of cardinals in which the attributes that reflect are expressible by infinitary formulas whose lengths can be strictly larger than the cardinal under consideration. This kind of generalized reflection…

Logic · Mathematics 2022-10-14 Brent Cody

We develop a generalized covering space theory for a class of uniform spaces called coverable spaces. Coverable spaces include all geodesic metric spaces, connected and locally pathwise connected compact topological spaces, in particular…

Algebraic Topology · Mathematics 2007-05-23 Valera Berestovskii , Conrad Plaut

We present the results of a study of the spectral properties of galaxies in the central part of the Shapley Concentration, covering an extremely wide range of densities, from the rich cluster cores to the underlying supercluster…

Astrophysics · Physics 2016-08-30 Alessandro Baldi , Sandro Bardelli , Elena Zucca

There are growing amount of very high-resolution polarized scattered light images of circumstellar disks. Nascent giant planets planets are surrounded by their own circumplanetary disks which may scatter and polarize both the planetary and…

Earth and Planetary Astrophysics · Physics 2021-06-16 J. Szulágyi , A. Garufi

One of the important microlensing applications to stellar atmospheres is the study of spots on stellar surface provided by the high resolution of caustic-crossing binary-lens events. In this paper, we investigate the characteristics of…

Solar and Stellar Astrophysics · Physics 2014-11-20 Kyu-Ha Hwang , Cheongho Han

Stars, and collections of stars, encode rich signatures of stellar physics and galaxy evolution. With properties influenced by both their environment and intrinsic nature, stars retain information about astrophysical phenomena that are not…

Astrophysics of Galaxies · Physics 2020-09-23 Kirsten Blancato

The observed evidence for the existence of strange stars and the concomitant observed masses and radii are used to derive an interpolation formula for the mass as a function of the radial coordinate. The resulting general mass function…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Farook Rahaman , Koushik Chakraborty , P. K. F. Kuhfittig , G. C. Shit , Mosiur Rahman

Let M be the moduli space of irreducible flat PSL(2,R) connections on a punctured surface of finite type with parabolic holonomies around punctures. By using a notion of admissibility of an ideal arc, M is covered by dense open subsets…

Geometric Topology · Mathematics 2007-05-23 R. M. Kashaev

The aim of this note is to complement and extend some recent results on Whitley's indices of thinness and thickness in three main directions. Firstly, we investigate both the indices when forming $\ell_p$-sums of Banach spaces, and obtain…

Functional Analysis · Mathematics 2014-05-28 Trond A. Abrahamsen , Johann Langemets , Vegard Lima , Olav Nygaard

We study additively graceful labelings of signed graphs on stars and double stars. While the case of signed stars is straightforward, the problem becomes significantly more intricate for signed double stars. We obtain a characterization of…

Combinatorics · Mathematics 2026-04-24 Brian DSouza , Jessica Pereira

The properties of a star with constant positive energy density inside (as for the Schwarzschild interior geometry) and a negative pressure are investigated, using a static conformally flat spacetime. Because of the negative pressure, the…

General Relativity and Quantum Cosmology · Physics 2025-04-08 Hristu Culetu

We define a topological space to be an "SDL space" if the closure of each one of its strongly discrete subsets is Lindel\"of. After distinguishing this property from the Lindel\"of property we make various remarks about cardinal invariants…

General Topology · Mathematics 2024-04-02 Angelo Bella , Santi Spadaro