A Linear Relation between the Color Stretch s BV and the Rising Color Slope s0*(B-V) of Type Ia Supernovae

Using data from the Complete Nearby (redshift z (host) < 0.02) sample of Type Ia Supernovae (CNIa0.02), we find a linear relation between two parameters derived from the B - V color curves of Type Ia supernovae: the color stretch s ( BV ) and the rising color slope s(0)*(B-V) BV . The s ( BV ) parameter is known to be tightly correlated with the peak luminosity, especially for fast decliners (dim Type Ia supernovae), and the luminosity correlation with s ( BV ) is markedly better than with the classic light-curve width parameters such as ?m (15)(B). Thus, our new linear relation can be used to infer peak luminosity from s(0)* s ( BV ) (or ?m (15)(B)), the measurement of s(0)*(B-V)

Automated summary

Using data from the Complete Nearby sample of Type Ia Supernovae with a redshift host less than 0.02, a linear relation between two parameters derived from the B - V color curves of Type Ia supernovae (s ( BV ) and s(0)*(B-V) BV ) was found. The s ( BV ) parameter is strongly correlated with peak luminosity, particularly for fast decliners, and this correlation is better than with the classic light-curve width parameters. Therefore, this new linear relation can be used to estimate peak luminosity from s(0)* s ( BV ) (or Δm (15) (B)) measurements.