Is there a way to convert distance modulus to get H(z) values

Hubble space.In summary, there is a request to convert distance modulus values to Hubble vs redshift H(z) data with standard deviation. However, it is mentioned that the data is currently in distance_modulus(z) space, making it impossible to directly convert to Hubble space.
  • #1
fab13
312
6
TL;DR Summary
I have a set of distance modulus and I would like to know if this is possible to convert these values into a Hubble vs redshift H(z) data ( with the standard deviation)
Hello,

Everything is in th summary :

I have a set of distance modulus and I would like to know if this is possible to convert numerically these values into a Hubble vs redshift H(z) data ( with the standard deviation).

Any relation between distance modulus and H(z) are welcome.

Regards
 
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  • #2
It's easy to convert distance modulus to distance. See this Wikipedia page for example. But do you also have redshift for these objects? How can you plot a Hubble curve without redshift data?
 
  • #3
@phyzguy

Of course, I forgot to mention that data are not in H(z) space but distance_modulus(z)

that's why I would like to handle them to get H(z) data

Thanks
 
  • #4
Redshifts are not in a fixed number of Hz. They are fractions of the original frequency,
 

1. How do I calculate H(z) values from distance modulus?

The formula for calculating H(z) from distance modulus is H(z) = 10^(mu/5 + 1), where mu is the distance modulus value. This formula is derived from the Hubble's law, which states that the recessional velocity of a galaxy is directly proportional to its distance from Earth.

2. Can I use any distance modulus value to calculate H(z)?

No, the distance modulus value used in the formula for H(z) must be measured or estimated from a standard candle, such as a Type Ia supernova or a Cepheid variable star. These objects have known intrinsic luminosities, which allows for accurate distance calculations.

3. What are the units of H(z)?

H(z) has units of kilometers per second per megaparsec (km/s/Mpc). This unit represents the rate of expansion of the universe at a given redshift (z).

4. How does converting distance modulus to H(z) help in studying the expansion of the universe?

Converting distance modulus to H(z) allows for the creation of a Hubble diagram, which plots the relationship between distance and recessional velocity of galaxies. This diagram can then be used to measure the expansion rate of the universe at different points in time, providing valuable insights into the evolution of the universe.

5. Are there any limitations to using H(z) values calculated from distance modulus?

Yes, there are several limitations to consider. The accuracy of H(z) values depends on the accuracy of the distance modulus measurements, which can be affected by various factors such as dust extinction and uncertainties in the standard candle's luminosity. Additionally, H(z) values may not accurately represent the true expansion rate of the universe due to the presence of dark energy and other unknown factors.

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