Converting units for Mass Estimates of Astronomical bodies

[Radiohannah]

Hello!
I'm new so I hope I've posted in the right place
One quickie please, if anyone can help me :-)
I hope to get my mass estimates in units of h₇₀^-1 x 10^{blah} M_sun

However! I have found some values in units of just x10^{blah} M_sun (*)
Where they have used h₅₀ in their calculations...

In order to convert it, should I divide my mass estimate (*) by this h₅₀ (so by '50' ) to get the units of h₅₀ ^-1, then convert it from there into h₇₀?

I'm asking because after I perform that calculation, the masses are significantly smaller than the values which are already quoted in units of h₇₀^-1 x 10^{blah} M_sun

Any help or guidance would be super appreciated! I'm quite baffled as to where I am going wrong :S

 

[lippyka]

Yes, you are correct in your calculation - you should divide your mass estimate by the h50 to get the units of h50-1. From there, you can multiply it by the ratio of h70 and h50 to get the units of h70-1. The difference in the values you're getting could be due to a few factors. First, it's possible that the values you're comparing against have been calculated using a slightly different cosmology or have been corrected for different effects. Second, if you're using different codes or methods to calculate your mass estimates, then the answers may differ due to differences in the assumptions and parameters used in each code/method. Finally, if you're using a sample of galaxies with a wide range of redshifts, then the Hubble parameter used in your calculations (h70 or h50) will also affect the results. This is because the Hubble parameter changes with redshift, and so you'll need to use the appropriate value for each galaxy when calculating its mass. I hope this helps!