Mass Profile in Elliptical Galaxies

In summary, Spiral Galaxies are well understood due to their visible internal structure, while Elliptical Galaxies are often obscured by their outer shell. However, there is a lack of non-theoretical data on the mass and density profiles of Elliptical Galaxies. This is because their shapes are not necessarily spherical and the variable R or r is not suitable due to the dependence on z. Additionally, the viewing angle also makes it difficult to obtain a comprehensive 3-dimensional picture of these galaxies. Some empirical fits, such as de Vaucouleurs' law, have been proposed based on luminosity.
  • #1
RCopernicus
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We know a fair amount about Spiral Galaxies because we can basically see their guts. Elliptical Galaxies are obscured by the outer shell. Can anyone direct me to some non-theoretical data on the mass (density) profile of Elliptical galaxies (i.e. the amount of mass (or density) at a given radius, R, from the center)?
 
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Ellipticals are not necessarily (or usually) spherical, so R is not a very good variable to discuss their shapes. Neither, really is r, because it depends on z. Also, we don't have a really good 3-d picture of these galaxies because of the unknown viewing angle. There are empirical fits to luminosities like de Vaucouleurs' law.
 

What is a mass profile in elliptical galaxies?

A mass profile in elliptical galaxies is a measurement of the distribution of mass within the galaxy. It shows how much mass is present at different distances from the center of the galaxy.

How is the mass profile in elliptical galaxies measured?

The mass profile is typically measured through observations of the galaxy's rotation curve, which shows how the speed of stars and gas changes with distance from the center. This can then be used to calculate the amount of mass present at different distances.

What can we learn from studying the mass profile in elliptical galaxies?

Studying the mass profile can provide insights into the formation and evolution of elliptical galaxies. It can also help us understand the distribution of dark matter within these galaxies, as well as the role of mergers and interactions in shaping their mass distribution.

How do mass profiles in elliptical galaxies compare to those in spiral galaxies?

Mass profiles in elliptical galaxies tend to have a steeper slope, meaning that the mass is more concentrated towards the center compared to spiral galaxies. This suggests that the formation processes for these two types of galaxies are different.

Are there any other factors that can affect the mass profile in elliptical galaxies?

Yes, the presence of supermassive black holes, as well as the distribution of dark matter, can also play a role in shaping the mass profile in elliptical galaxies. Additionally, the age and history of the galaxy can also impact its mass profile.

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