How to calculate distance to other galaxies using type 1a supernova?

This is for a project in astronomy with extensive data analysis. How should I calculate the distance of galaxies using AGN and supernova Ia? I am using the data from dr17 of SDSS.

• What have you already tried? Type Ia have absolute magnitudes of -19.3, so you probably could use inverse square law given you have magnitude of the Ia in said galaxy. Jan 31, 2022 at 18:19
• @fasterthanlight But who ever has that information? Jan 31, 2022 at 19:18

$$M=-21.726+2.698\cdot \Delta m$$
where $$\Delta m$$ is the observed decline of the B-magnitude 15 days after maximum.
With the observed apparent magnitude $$m$$ you have then the distance modulus $$m-M$$ and thus the distance $$d$$
$$d=10^{1+(m-M)/5} \ \mathrm{Parsecs}$$