Hello everyone.
We infer the luminosity distance from the detector data; once we get the luminosity distance, we estimate the redshift.
How exactly do we estimate the redshift, and does the analysis differ from what the cosmological model assumes for each event?
I noticed the datasets contain a “redshift” column. The redshift value corresponds to each luminosity distance posterior value; thus, the redshift is estimated from the previous prior.
So, do the adopted cosmological models affect the results, and do the models change? Like for example, the estimated redshift model used for the first observing run other than the current measurement?
Can anyone help me with answering this issue or tell me where I can find further explanation?
In short, yes! To get redshift from the GWs luminosity distance, you have to assume a cosmology. Usually the cosmology chosen is referred in each paper - for example here, Appendix E.
Hello @MariosKal Thank you for your answer.
So, we have to assume a certain cosmological model for each event, and if the posterior data contains redshift values that means it’s inferred from the luminosity distance and a cosmological model was used? And how could the analysis differ if we choose different cosmological models
No, a fiducial cosmology is chosen and is used for all events. In each paper, it should be mentioned which one chosen.
If a different model is used, your quantities that depend on redshift would be different. For example, if for the same distances you choose a smaller $H_0$ (Hubble constant), you’ll get a smaller redshift (you can check the Hubble law here, for a rough estimate)