相关论文: The Norma spiral arm: large-scale pitch angle

Here we fitted a 4-arm spiral structure to the more accurate data on global arm pitch angle and arm longitude tangents, to get the start of each spiral arm near the Galactic nucleus. We find that the tangent to the 'start of the…

We carry out analyses of some parameters of the galactic spiral arms, in the currently available samples. We present a catalog of the observed pitch angle for each spiral arm in the Milky Way disk. For each long spiral arm in the Milky Way,…

There are many published values for the pitch angle of individual spiral arms, and their wide distribution (from -3 to -28 degrees) begs for various attempts for a single value. Each of the four statistical methods used here yields a mean…

We have measured the positions of large numbers of H II regions in four nearly face-on, late-type, spiral galaxies: NGC 628 (M 74), NGC 1232, NGC 3184 and NGC 5194 (M 51). Fitting log-periodic spiral models to segments of each arm yields…

We present a detailed photometric study and measurements of spiral arm pitch angles for a sample of 50 non-barred or weakly barred grand-design spiral galaxies selected from Sloan Digital Sky Survey. In order to find pitch angles, we used a…

We report measurements of parallaxes and proper motions of ten high-mass star-forming regions in the Sagittarius spiral arm of the Milky Way as part of the BeSSeL Survey with the VLBA. Combining these results with eight others from the…

We report measurements of trigonometric parallaxes for six high-mass star-forming regions in the Scutum spiral arm of the Milky Way as part of the BeSSeL Survey. Combining our measurements with 10 previous measurements from the BeSSeL…

A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have…

One of the key parameters that characterize spiral arms in disk galaxies is a pitch angle that measures the inclination of a spiral arm to the direction of galactic rotation. The pitch angle differs from galaxy to galaxy, which suggests…

Using data from the Southern Galactic Plane Survey we present a possible distant spiral arm in the fourth quadrant of the Milky Way. The very distinct and cohesive feature can be traced for over 70 deg as the most extreme positive velocity…

Trigonometric parallax measurements of nine water masers associated with the Local arm of the Milky Way were carried out as part of the BeSSeL Survey using the VLBA. When combined with 21 other parallax measurements from the literature, the…

To estimate the parameters of the Galactic spiral structure - namely, the pitch angle i and the number of spiral arms,- data on Galactic masers with known trigonometric parallaxes were used. We applied the well-known method based on…

We have investigated the pitch angle ($\psi$) of the spiral arms of galaxies in the Hubble Space Telescope COSMOS field. The sample consists of 102 face-on galaxies with a two-armed pattern at a mean redshift $\langle z \rangle \approx…

Spiral galaxies are observed to exhibit a range of morphologies, in particular in the shape of spiral arms. A key diagnostic parameter is the pitch angle, which describes how tightly wound the spiral arms are. Observationally and…

Pulsars provide unique probes of the large-scale interstellar magnetic field in the Galactic disk. Up to now, the limited Galactic distribution of the known pulsar population has restricted these investigations to within a few kiloparsec of…

The origin and maintenance of spiral structure in galaxies, the correlation between different types of spiral structure and several proposed mechanisms for their generation, and the evolution of spiral arms of galaxies with time are…

In this work we determine the parameters of spiral structure for a sample of face-on spiral galaxies. In practice, the solution of this problem is a hard task because of the diversity of the observed characteristics of spiral structure,…

Spiral structure is ubiquitous in the Universe, and the pitch angle of arms in spiral galaxies provide an important observable in efforts to discriminate between different mechanisms of spiral arm formation and evolution. In this paper, we…

In spiral galaxies, the pitch angle, $\alpha$, of the spiral arms is often proposed as a discriminator between theories for the formation of the spiral structure. In Lin-Shu density wave theory, $\alpha$ stays constant in time, being simply…

We consider the problem of determining the geometric parameters of a Galactic spiral arm from its segment by including the distance to the spiral pole, i.e., the distance to the Galactic center ($R_0$). The question about the number of…