Are Freeman's Law and the Tully-Fisher Relationship the Same?

[jam12]

Homework Statement

Hello I wanted clarification on freeman's law and the Tully fisher relationship.

Am i correct to say that the tully fisher relationship that states
L=kv^4 where L=luminosity of galaxy and v= max rotational speed of galaxy.
only applies to edge-on spiral galaxies.

what is the general relationship between the luminosity of any edge on galaxy and its rotational speed (not max rational speed)? Is this the freeman's law? (if so what does this law state)

I have looked on numerous webpages and am quite confused in the two laws.
Thanks in advance

 

[member 553083]

.Homework Equations L=kv^4 The Attempt at a SolutionFreeman's law is the observed relationship between the maximum rotational velocity, Vmax, of a spiral galaxy and its luminosity. It states that for a given type of spiral galaxy, there is a linear relationship between the rotational velocity and the fourth root of its luminosity, which can be expressed as Vmax∝L1/4. This law was first proposed by Freeman in 1970 based on observations of a sample of 21 nearby spiral galaxies. The Tully-Fisher relation is a similar relationship, but between the luminosity of a spiral galaxy and its maximum rotational velocity. It states that for a given type of spiral galaxy, there is a linear relationship between the luminosity and the fourth power of its rotational velocity, which can be expressed as L∝Vmax^4. This law was first proposed by Tully and Fisher in 1977 based on observations of a sample of 28 nearby spiral galaxies.