Using Type Ia Supernovae to Measure Distances

Type Ia supernovae are scattered throughout the Universe in many different galaxies. To find the distance to these galaxies use these four steps:

1. Fit a model light curve to the data, paying particular attention to the part from the peak to 15 days after the peak (the 𝚫m₁₅).

2. Determine the peak apparent magnitude from the light curve.

3. Use the 𝚫m₁₅ from the model curve to determine the peak absolute magnitude of the supernova.

4. Use the peak apparent and absolute magnitudes to calculate the distance to the supernova.

Watch this animation to better understand how to fit a model light curve to data and determine the 𝚫m_15.