Results 101 to 110 of about 443,565 (219)

Modified Newtonian Dynamics: A Falsification of Cold Dark Matter

Advances in Astronomy, 2009
The only viable alternative to dark matter is one in which Newtonian dynamics or gravity breaks down in the limit of low accelerations, as in modified Newtonian dynamics (MONDs).
R. H. Sanders
doaj   +1 more source

Magnetic-Field Vector Maps of Nearby Spiral Galaxies

Galaxies, 2019
We present a method for determining the directions of magnetic-field vectors in a spiral galaxy using two synchrotron polarization maps, an optical image, and a velocity field.
Hiroyuki Nakanishi, Kohei Kurahara, Kenta Anraku   +2 more
doaj   +1 more source

Modelling Spiral Galaxies [PDF]

, 2023
We develop a new technique to equip models of spiral galaxies with self-consistent dynamics that match observations. We apply our technique and construct a model for the Milky Way with a dynamical interstellar medium (ISM).
Frenkler, Joachim
core  

Spin Parity of Spiral Galaxies. VI. A Search for Dynamical Memory in the Spin Distribution of Galaxies in HSC WIDE Survey Regions

The Astronomical Journal
We analyzed the distribution of spin parity in spiral galaxies using the HSC DR2 data. The spiral winding parity of disk galaxies, observed as S-spiral or Z-spiral projected onto the sky plane, provides robust information on the sign of the line-of-sight
Masanori Iye, Masafumi Yagi
doaj   +1 more source

A fundamental plane of spiral structure in disk galaxies [PDF]

, 2015
Spiral structure is the most distinctive feature of disk galaxies and yet debate persists about which theory of spiral structure is correct. Many versions of the density wave theory demand that the pitch angle be uniquely determined by the distribution ...
Flatman, Russell, Daniel Kennefick, Davis, Benjamin L., Hartley, Matthew T., Thomas P. K. Martinsson, Julia Kennefick, Kennefick, Julia, Shields, Douglas W., Berrier, Joel C., Westfall, Kyle B., Martinsson, Thomas P. K., Kyle B. Westfall, Douglas W. Shields, Kennefick, Daniel, Benjamin L. Davis, Swaters, Rob A., Russell Flatman, Joel C. Berrier, Rob A. Swaters, Matthew T. Hartley   +19 more
core   +1 more source

The Impacts of Bars, Spirals, and Bulge Size on Gas-phase Metallicity Gradients in MaNGA Galaxies

The Astrophysical Journal
As galaxies evolve over time, the orbits of their constituent stars are expected to change in size and shape, moving stars away from their birth radius. Radial gas flows are also expected. Spiral arms and bars in galaxies are predicted to help drive this
M. E. Wisz, Karen L. Masters, Kathryne J. Daniel, David V. Stark, Francesco Belfiore   +4 more
doaj   +1 more source

From gas to stars along the spiral wave: CO, HCN, and star formation variations across the spiral arms in NGC 4321 and M51

Astronomy & Astrophysics
Context. Molecular clouds form stars from the interstellar medium via gravitational collapse, following a sequence from low-density gas to high-density cores and eventually the formation of stars. In classical density wave theory, gas clouds orbiting the
Greve Minou, Neumann Lukas, Thorp Mallory, Colombo Dario, Bigiel Frank, Querejeta Miguel, Meidt Sharon E., Barnes Ashley T., Bazzi Zein, Klessen Ralf S., Leroy Adam K., Pan Hsi-An, Pety Jérôme, Ruiz-García Marina, Schinnerer Eva, Smith Rowan, Stuber Sophia, Sun Jiayi, Usero Antonio, Williams Thomas G.   +19 more
doaj   +1 more source

Magnetic spiral arms in galaxies

Large-scale magnetic fields in spiral galaxies are strongest in spiral-shaped regions, the magnetic arms. It was recently discovered for the galaxy NGC 6946 that magnetic arms can be interlaced with the gaseous arms, rather than coinciding with them ...
Shukurov A
core   +4 more sources

On the Role of Noncircular Motions in MaNGA Galaxies. I. Global Properties

The Astrophysical Journal
Noncircular (NC) motions represent the imprints of nonaxisymmetric structures in galaxies, providing opportunities to study the physical properties of gas departing from circular rotation.
Carlos López-Cobá, Lihwai Lin, Justus Neumann, Matthew A. Bershady   +3 more
doaj   +1 more source

Polarimetric Observations of Spiral Galaxies

Publications of the Astronomical Society of the Pacific, 1967
The extragalactic systems NCC 3031, NCC 4594, NGC 5194, and NGC 5457 have been observed polarimetrically. Linear polarization between 0.1 and 1.0 percent was detected in the spiral arms of all four galaxies. The planes of vibration indicate that reflection as well as interstellar absorption of starlight by the internal dust clouds of the observed ...
openaire   +1 more source