Results 41 to 50 of about 144,718 (240)

Galactic Density and Evolution Based on the Virial Theorem, Energy Minimization, and Conservation of Angular Momentum

open access: yesGalaxies, 2018
Spiral galaxies are spinning, internally densified objects. The Virial Theorem explains galactic rotation curves via its linkage of the rotation rate to the gravitational self-potential (Ug) and the moment of inertia of oblate spheroids.
Robert E. Criss, Anne M. Hofmeister
doaj   +1 more source

The optical polarization of spiral galaxies [PDF]

open access: yesMonthly Notices of the Royal Astronomical Society, 2000
Scattering of starlight by dust, molecules and electrons in spiral galaxies will produce a modification of the direct intensity and a polarization in the observed light. We treat the case where the distribution of scatterers can be considered to be optically thin, and derive semi-analytic expressions for the resolved intensity and polarized intensity ...
Edouard Audit, John F. L. Simmons
openaire   +4 more sources

Extragalactic Magnetism with SOFIA (SALSA Legacy Program). V. First Results on the Magnetic Field Orientation of Galaxies

open access: yesThe Astrophysical Journal, 2023
We present the analysis of the magnetic field ( B -field) structure of galaxies measured with far-infrared (FIR) and radio (3 and 6 cm) polarimetric observations.
Alejandro S. Borlaff   +15 more
doaj   +1 more source

Gravitational Instability of Gas–Dust Circumnuclear Disks in Galaxies

open access: yesGalaxies, 2023
We numerically study the origin of the multi-armed spiral structure observed in the circumnuclear gaseous mini-disks of nearby galaxies. We show that the presence of dust in such disks and its interaction with the gravitationally stable gaseous component
Roman Tkachenko   +2 more
doaj   +1 more source

Nuclear Spirals in Galaxies [PDF]

open access: yes, 2008
6 pages, 4 figures, to appear in ""Mapping the Galaxy and Nearby Galaxies", Eds. K. Wada and F.
openaire   +3 more sources

A Catalog of Photometric Redshift and the Distribution of Broad Galaxy Morphologies

open access: yesGalaxies, 2018
We created a catalog of photometric redshift of ∼3,000,000 SDSS galaxies annotated by their broad morphology. The photometric redshift was optimized by testing and comparing several pattern recognition algorithms and variable selection strategies, and ...
Nicholas Paul   +2 more
doaj   +1 more source

Nonlinear Density Wave Theory in a Gaseous Disk

open access: yesThe Astronomical Journal, 2023
A nonlinear solution for the gaseous component of a galactic disk has been derived self-consistently using fluid description and reductive perturbation theory. We show that gas follows a spiral pattern, similarly to the stellar component; but the spirals
Miroslava Vukcevic
doaj   +1 more source

Assembling Spiral Galaxies [PDF]

open access: yesSymposium - International Astronomical Union, 1996
Nearby spiral galaxies offer vital clues to some of the most fundamental questions about galaxy formation and evolution: What is the star formation history of the universe, past and future? When did disks form, during the final stages of a single primeval collapse, or as a continuous or episodic process?
openaire   +2 more sources

ULTRALIGHT SCALARS AND SPIRAL GALAXIES [PDF]

open access: yesModern Physics Letters A, 2001
We study some possible astrophysical implications of a very weakly coupled ultralight dilaton-type scalar field. Such a field may develop an (approximately stable) network of domain walls. The domain wall thickness is assumed to be comparable with the thickness of the luminous part of the spiral galaxies. The walls provide trapping for galactic matter.
Gregory Gabadadze   +2 more
openaire   +4 more sources

Exploring the evolution of spiral galaxies [PDF]

open access: yesMonthly Notices of the Royal Astronomical Society, 2002
We have constructed a family of simple models for spiral galaxy evolution to allow us to investigate observational trends in star formation history with galaxy parameters. The models are used to generate broad band colours from which ages and metallicities are derived in the same way as the data.
Eric F. Bell   +2 more
openaire   +3 more sources

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