Understanding Rotation Curves: A Study of Galactic Density and Derivatives

In summary, the conversation discusses the calculation of the curve rotation, specifically the equation V^2=-8GR∫0∞rdz[∂p(r,z)/∂r][K(p)-E(p)]/√(Rrp), where p(x) = x-√(x^2-1), x = (R^2+u^2+z^2)/(2Rr), and p(r,z) = p0e^(-r/h)[ch(z/z0)]^-2. The conversation also mentions the derivative of p(u,z) with respect to u, which is given by -p0e^(-r/h)[ch(z/z0)]^-2/h. The original
  • #1
Dan_
2
0
Hello, I make the calculation of the curve rotation. Casertano(1982г.)
[itex]V^{2}=-8GR \int_{0}^{\infty}{r} \int_{0}^{\infty}{ [\frac {\partial p(r,z)} {\partial r}] \frac {K(p)-E(p)} {\sqrt{R r p}}}dzdr[/itex]
[itex]p = x - \sqrt{x^{2}-1} x=(R^{2}+u^{2}+z^{2})/(2Rr)[/itex]
Density
[itex]p(r,z) = p_{0} \exp(-r/h) [ch(z/z_{0})]^{-2}[/itex]
Derivative
[itex]\frac {\partial p(u,z)} {\partial u} = \frac {-p_{0} \exp(-r/h) [ch(z/z_{0})]^{-2}} {h}[/itex]
Original article http://articles.adsabs.harvard.edu//full/1983MNRAS.203..735C/0000737.000.html
The problem is this. Double integral should be limited. I do not know how.
 
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  • #2
Calculation in C# http://pastebin.com/Dx4xkzYy
 

Related to Understanding Rotation Curves: A Study of Galactic Density and Derivatives

What is a rotation curve?

A rotation curve is a graphical representation of the rotational velocity of an object, such as a galaxy or a planet, as a function of its distance from the center of rotation. It can provide information about the mass distribution within the object.

How is a rotation curve measured?

A rotation curve is typically measured by observing the Doppler shift of spectral lines from different parts of the rotating object. This allows scientists to determine the rotational velocity at different distances from the center.

What is the significance of the Casertano rotation curve?

The Casertano rotation curve is a famous example of a rotation curve for a spiral galaxy, specifically the galaxy NGC 3198. It is significant because it showed a flat rotation curve, which contradicted the predicted rotational velocities based on the visible mass of the galaxy. This led to the discovery of dark matter.

How does the rotation curve of a galaxy relate to dark matter?

The rotation curve of a galaxy is used to determine the mass distribution within the galaxy. In many cases, the observed rotational velocities do not match the predicted velocities based on the visible mass. This discrepancy is often attributed to the presence of dark matter, which is believed to make up a large portion of the mass of galaxies.

What other objects can have rotation curves?

Rotation curves can be measured for any object that rotates, such as planets, stars, and galaxies. They can also be used to study the rotational motion of non-physical systems, such as molecular clouds or accretion disks.

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