Unuasual rotation curve of the galaxy NGC 2814

Astrophysics ◽  
1983 ◽  
Vol 18 (3) ◽  
pp. 205-209
Author(s):  
N. K. Andreasyan ◽  
�. E. Khachikyan
Keyword(s):  
Rotation Curve ◽  
The Galaxy

scholarly journals The rotation curve, mass, light, and velocity distribution of M31

1970 ◽  
Vol 38 ◽  
pp. 51-60
Author(s):  
J. Einasto ◽  
U. Rümmel
Keyword(s):  
Spectroscopic Data ◽  
Total Mass ◽  
Rotation Curve ◽  
Mass Density ◽  
Major Axis ◽  
Deviation Angle ◽  
Andromeda Galaxy ◽  
The Galaxy ◽  
M 31 ◽  
Central Concentration

A model for the Andromeda galaxy, M 31, has been derived from the available radio, photometric, and spectroscopic data. The model consists of four components – the nucleus, the bulge, the disc, and the flat component.For all components the following functions have been found: the mass density; the mass-to-light ratio; the velocity dispersions in three perpendicular directions (for the plane of symmetry and the axis of the galaxy); the deviation angle of the major axis of the velocity ellipsoid from the plane of symmetry; the centroid velocity (for the plane of symmetry).Our model differs in two points from the models obtained by other authors: the central concentration of mass is higher (in the nucleus the mass-to-light ratio is about 170), and the total mass of the galaxy (200 × 109 solar masses) is smaller. The differences can be explained by different rotation curves adopted, and by attributing more weight to photometric and spectroscopic data in the case of our model.

scholarly journals On a possible corrugation of the galactic plane

1970 ◽  
Vol 38 ◽  
pp. 147-150 ◽  
Author(s):  
C. M. Varsavsky ◽  
R. J. Quiroga
Keyword(s):  
Brightness Temperature ◽  
Solid Body ◽  
Rotation Curve ◽  
Galactic Plane ◽  
Maximum Temperature ◽  
Body Rotation ◽  
Maximum Brightness ◽  
Solid Body Rotation ◽  
The Galaxy ◽  
Sinusoidal Pattern

We have studied the rotation curve of the Galaxy at different heights below and above the equator. In the course of this work we noticed that the maximum brightness temperature of hydrogen oscillates around the galactic plane following a fairly sinusoidal pattern. It is further noticed that the maximum temperature of hydrogen occurs right on the plane in the regions where the rotation curve has a form indicating solid body rotation. A rotation curve based on points of maximum hydrogen temperature does not differ appreciably from a rotation curve measured on the galactic plane.

scholarly journals The Massive Dark Corona Of Our Galaxy

1996 ◽  
Vol 173 ◽  
pp. 175-176
Author(s):  
K.C. Freeman
Keyword(s):  
Rotation Curve ◽  
Spiral Galaxies ◽  
Galactic Center ◽  
Galactic Disk ◽  
Galactic Rotation ◽  
Rotation Curves ◽  
Stellar Component ◽  
The Galaxy ◽  
Galactic Rotation Curve

From their rotation curves, most spiral galaxies appear to have massive dark coronas. The inferred masses of these dark coronas are typically 5 to 10 times the mass of the underlying stellar component. I will review the evidence that our Galaxy also has a dark corona. Our position in the galactic disk makes it difficult to measure the galactic rotation curve beyond about 20 kpc from the galactic center. However it does allow several other indicators of the total galactic mass out to very large distances. It seems clear that the Galaxy does indeed have a massive dark corona. The data indicate that the enclosed mass within radius R increases like M(R) ≈ R(kpc) × 1010M⊙, out to a radius of more than 100 kpc. The total galactic mass is at least 12 × 1011M⊙.

The Schwarzschild solution to the Nexus graviton field

2015 ◽  
Vol 12 (04) ◽  
pp. 1550042 ◽  
Author(s):  
Stuart Marongwe
Keyword(s):  
Rotation Curve ◽  
Transition Process ◽  
Cosmic Acceleration ◽  
Late Time ◽  
Field Equations ◽  
Coincidence Problem ◽  
Schwarzschild Solution ◽  
The Galaxy ◽  
Hubble Radius ◽  
Time Changes

The Schwarzschild approach is applied to solve the field equations describing a Nexus graviton field. The resulting solutions are free from singularities which have been a problem in general relativity since its inception. Findings from this work also demonstrate that at the Hubble radius, the metric signature of space-time changes generating short-lived but intense bursts of energy during the transition process. The solutions in this paper also provide an explanation to the enigma of late time cosmic acceleration, the galaxy rotation curve problem and the coincidence problem.

scholarly journals The Galactic Rotation Curve to R = 18 Kpc

1980 ◽  
Vol 87 ◽  
pp. 213-220 ◽  
Author(s):  
Leo Blitz ◽  
Michel Fich ◽  
Antony A. Stark
Keyword(s):  
Rotation Curve ◽  
Hii Regions ◽  
Molecular Gas ◽  
Galactic Rotation ◽  
Galactocentric Distance ◽  
The Past ◽  
The Galaxy ◽  
Galactic Rotation Curve ◽  
Sizable Number

The major stumbling block in the determination of a rotation curve beyond the solar circle has been the lack of a suitable set of objects with well defined and independently measured distances and velocities which can be observed to large galactocentric radii. Two things have changed this situation. The first was the realization that essentially all local HII regions have associated molecular material. The second was the acquisition of reliable distances to the stars exciting a sizable number of HII regions at large galactocentric radii (Moffat, FitzGerald, and Jackson 1979). Because the velocity of the associated molecular gas can be measured very accurately by means of radio observations of CO, we have been able to overcome the past difficulties and have measured the rotation curve of the Galaxy to a galactocentric distance of 18 kpc.

scholarly journals Simple models of galactic bulges

1993 ◽  
Vol 153 ◽  
pp. 361-362
Author(s):  
N.W. Evans
Keyword(s):  
Distribution Function ◽  
Gravity Field ◽  
Rotation Curve ◽  
Logarithmic Potential ◽  
Axisymmetric Model ◽  
The Galaxy ◽  
Flat Rotation Curve ◽  
Simple Models

We present a simple axisymmetric model with an elementary distribution function capable of representing galactic bulges. The gravity field of the galaxy is based on the axisymmetric logarithmic potential, which has a flat rotation curve. Bulges are built as isothermal distributions of stars embedded within the potential.

scholarly journals Longslit spectroscopy of the peculiar Seyfert 2 galaxy HRG 10103

2010 ◽  
Vol 6 ◽  
pp. 11-16
Author(s):  
Paulo C.R. Poppe ◽  
Vera A.F. Martin ◽  
Max Faúndez-Abans ◽  
Mariângela De Oliveira-Abans ◽  
Iranderly F. De Fernandes
Keyword(s):  
Spectroscopic Data ◽  
Rotation Curve ◽  
Abundance Ratio ◽  
Emission Lines ◽  
Physical Parameters ◽  
Narrow Line ◽  
Optical Range ◽  
Peculiar Galaxy ◽  
The Galaxy ◽  
The Continuum

We present the rst optical longslit spectroscopy for the galaxy HRG 10103, an Sa(r) type peculiar galaxy seen face-on with an asymmetrical elliptical structure. The main goal of this work is to provide the spectral classication of the current object using the `traditional' diagnostic diagrams. However, we also present a diagnostic involving the known emission line ratio R23, usually used to estimate the O/H abundance ratio. The idea is to make a better distinction between the narrow-line AGNs and the H II galaxies. The spectra were obtained in two observatories (OPD-LNA/MCT and Gemini-South) and includes some of the most important emission lines for ionization diagnostic. Based on the observed spectra, HRG 10103 is a Seyfert 2 galaxy with typical line-ratios values in the optical range. We have estimated nuclear redshift of z = 0.039. The resulting reddening values as a function of distance from the nucleus are presented too. The errors in the  fluxes were mostly caused by uncertainties in the placement of the continuum level. The rotation curve is typical of spiral disks, rising shallowly and  attening at an observed amplitude of about 200 km s^(-1). Some other physical parameters have been derived whenever possible. The spectroscopic data reduction was carried out using the GEMINI.GMOS package as well as the standard IRAF procedures.

The Rotation Curve from A-F Supergiants

1996 ◽  
Vol 169 ◽  
pp. 703-706
Author(s):  
D. M. Peterson ◽  
D. Slowik
Keyword(s):  
Total Mass ◽  
Rotation Curve ◽  
Galactic Center ◽  
Galactic Rotation ◽  
The Sun ◽  
Critical Information ◽  
New Class ◽  
The Galaxy ◽  
Local Distance

The Galactic rotation law provides critical information for estimating the distribution of mass in the Galaxy, for tying the distance of the Sun from the Galactic center to local distance scales, and, if determined over large enough distances, for estimating the total mass of the system and the amount of nonluminous matter present. Interior to the Sun velocities are well defined by observations of the ISM, particularly HI. These techniques are not available for points exterior to the Sun and we must rely on observations of velocities of objects whose distances can be estimated. Notable among these are the Cepheids (Pont et al 1994) and the combination of CO velocities and OB cluster distances (Brand & Blitz 1993) where the two are found to coexist. Adding a new class of objects, particularly bright, relatively common objects to this effort is of importance.

scholarly journals Dynamical Effects in the Central Region of the Galaxy

1977 ◽  
Vol 45 ◽  
pp. 103-113 ◽  
Author(s):  
Robert H. Sanders
Keyword(s):  
Density Distribution ◽  
Central Region ◽  
Molecular Clouds ◽  
Rotation Curve ◽  
Disk Model ◽  
Gas Density ◽  
Spherical Component ◽  
The Galaxy

For the purpose of this Paper, I will define the central region of the galaxy as being the inner four kiloparsecs. I make this definition for three reasons:1) Outside of four kiloparsecs, the rotation curve for the galaxy is well-defined by the Schmidt disk model; whereas, inside four kiloparsecs, the effects of a central spherical component on the rotation curve become conspicuous. This inner spheroid is a dynamical component of the galaxy which is distinct from the disk and may be distinct from the extended halo component as well.2) There is a conspicuous hole in the total gas density distribution inside 4 kpc.3) High peculiar or non-circular gas velocities are observed within the inner 4 kpc; velocities ranging from the 53 km s-1of the so-called 3 kpc arm, to 165 km s-1in the molecular clouds within 300 pc of the center.I will now discuss these points in some greater detail.

scholarly journals Models of the mass distribution of the Galaxy

1985 ◽  
Vol 106 ◽  
pp. 75-84
Author(s):  
Maarten Schmidt
Keyword(s):  
Gravitational Field ◽  
Mass Distribution ◽  
Rotation Curve ◽  
The Galaxy

Mass models of the Galaxy play an important role in studies of the structure of the Galaxy. The various populations or components combine to yield a gravitational field that produces the observed rotation curve. For the spheroid and disk this requirement can be used to set limits on some of their properties. The properties of the dark corona are entirely defined this way.

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