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Junji

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Hi!

I want to estimate the distance and mass of a galaxy by given values.

The center of an inclined galaxy sends out light of a certain wavelength (f.ex. the HI line) out to a certain radius r.

At the outer edges of the galaxy the emitted line has a wavelength of l +/- dl

At first, I thought the distance is calculated by using the redshift principle. However, this would mean that one edge has a redshift whereas the other one has a blueshift, so the galaxy plane would be rotating. Can this be possible?

Yet, I don't know why else there are observed different wavelengths at the edges and why the center wavelength is observed out to a radius r. Any ideas?

If my first thought was right, I get to the following equation:

The formula for the redshift is given as c*z = H*d , with redshift z = dl/l and Hubble constant H.

So the distance for the more distance edge would be d = c*(dl/l)/H, right?

However, I don't have any ideas so far, how to estimate the mass of a galaxy.

Is there some relation between the emitted wavelengths and its mass at all?

Thank you in advance!

Junji

I want to estimate the distance and mass of a galaxy by given values.

The center of an inclined galaxy sends out light of a certain wavelength (f.ex. the HI line) out to a certain radius r.

At the outer edges of the galaxy the emitted line has a wavelength of l +/- dl

At first, I thought the distance is calculated by using the redshift principle. However, this would mean that one edge has a redshift whereas the other one has a blueshift, so the galaxy plane would be rotating. Can this be possible?

Yet, I don't know why else there are observed different wavelengths at the edges and why the center wavelength is observed out to a radius r. Any ideas?

If my first thought was right, I get to the following equation:

The formula for the redshift is given as c*z = H*d , with redshift z = dl/l and Hubble constant H.

So the distance for the more distance edge would be d = c*(dl/l)/H, right?

However, I don't have any ideas so far, how to estimate the mass of a galaxy.

Is there some relation between the emitted wavelengths and its mass at all?

Thank you in advance!

Junji

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