Shortening the baseline: characterising Type Ia supernovae using Δ m 10( X )
11 affiliations
- 1Astrophysics Research Institute, Liverpool John Moores University , IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF ,
- 2Max-Planck-Institut für Astrophysik , Karl-Schwarzschild-Str 1, D-85748 Garching ,
- 3Institute for Astronomy, University of Hawaii , 2680 Woodlawn Dr, Honolulu, HI 96822 ,
- 4Observatories of the Carnegie Institution for Science , 813 Santa Barbara St, Pasadena, CA 91101 ,
- 5Carnegie Observatories , Las Campanas Observatory, Colina El Pino, Casilla 601 ,
- 6Institute of Space Sciences (ICE-CSIC) , Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona ,
- 7Institut d’Estudis Espacials de Catalunya (IEEC) , E-08860 Castelldefels (Barcelona) ,
- 8Department of Physics and Astronomy, Aarhus University , Ny Munkegade 120, DK-8000 Aarhus C ,
- 9Department of Physics, Florida State University , 77 Chieftan Way, Tallahassee, FL 32306 ,
- 10Center for Astronomy, Space Science and Astrophysics, Independent University , Bashundhara R/A, Dhaka 1229 ,
- 11American Public University System , 111 W. Congress St, Charles Town, WV 25414 ,
Abstract
An explorative study of Type Ia supernovae (SNe Ia) light curves is presented. Δ mt(X) decline-rate metrics are used to evaluate alternative characterisations of light-curve diversity and the luminosity–width relation (LWR). Using a sample of 362 SNe Ia from the Carnegie Supernova Project (CSP-I and CSP-II), Gaussian process regression is used to fit B- and g-band light curves and measure decline-rates across multiple post-maximum time-scales. The LWR is calibrated using a clean subsample of SNe Ia with host-independent distance moduli and Fitzpatrick (1999) reddening corrections. Decline-rates Δ m10(B) and Δ m10(g) are found to capture the LWR effectively, while mitigating the severe degeneracy that affects longer time-scales for fast-declining (Δ m15(B) ≥ 1.6 mag) events. Continuous, piecewise linear models are presented that seamlessly anchor the transition between normal and fast-declining regimes. The decline-rate Δ m10(X) closely approximates the results of the more complex colour-stretch parameters, requiring less post-maximum temporal coverage than Δ m15(B) or sBV, and offers an even greater sensitivity for slow decliners. Δ m10(B) provides a precise and practical tool for large-scale photometric surveys and real-time observer classification.
Versions
Related
- Flashing with colours: Photometric indicators of an early interaction in type II supernovae
- An improved standardization framework for Type II-P supernovae using a hierarchical Bayesian approach
- Searching for Type Ia Supernovae in the Dark Energy Spectroscopic Instrument
- Supernovae Unite: Host-Galaxy Mass Measurements of Type Ia Supernovae and Their Impact on Cosmology
- Study of dynamical dark energy using DESI DR2 BAO, CMB, and Type Ia Supernovae data
BibTeX
@article{velasco2026shortening,
title = {{Shortening the baseline: characterising Type Ia supernovae using Δ m 10( X )}},
author = {Joel M Velasco and Paolo A Mazzali and Christopher Ashall and Christopher R Burns and Mark M Phillips and Lluis Galbany and Nidia Morrell and Maximilian D Stritzinger and Peter Hoeflich and Eric Y Hsiao and Syed A Uddin},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = oct,
doi = {10.1093/mnras/stag1907},
url = {https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1907/8876083},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Shortening the baseline: characterising Type Ia supernovae using Δ m 10( X )
AU - Joel M Velasco
AU - Paolo A Mazzali
AU - Christopher Ashall
AU - Christopher R Burns
AU - Mark M Phillips
AU - Lluis Galbany
AU - Nidia Morrell
AU - Maximilian D Stritzinger
AU - Peter Hoeflich
AU - Eric Y Hsiao
AU - Syed A Uddin
PY - 2026
DA - 2026/10/07
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/stag1907
UR - https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1907/8876083
AB - An explorative study of Type Ia supernovae (SNe Ia) light curves is presented. Δ m_t(X) decline-rate metrics are used to evaluate alternative characterisations of light-curve diversity and the luminosity–width relation (LWR). Using a sample of 362 SNe Ia from the Carnegie Supernova Project (CSP-I and CSP-II), Gaussian process regression is used to fit B- and g-band light curves and measure decline-rates across multiple post-maximum time-scales. The LWR is calibrated using a clean subsample of SNe Ia with host-independent distance moduli and Fitzpatrick (1999) reddening corrections. Decline-rates Δ m_10(B) and Δ m_10(g) are found to capture the LWR effectively, while mitigating the severe degeneracy that affects longer time-scales for fast-declining (Δ m_15(B) ≥ 1.6 mag) events. Continuous, piecewise linear models are presented that seamlessly anchor the transition between normal and fast-declining regimes. The decline-rate Δ m_10(X) closely approximates the results of the more complex colour-stretch parameters, requiring less post-maximum temporal coverage than Δ m_15(B) or s_BV, and offers an even greater sensitivity for slow decliners. Δ m_10(B) provides a precise and practical tool for large-scale photometric surveys and real-time observer classification.
SN - 0035-8711
SN - 1365-2966
ER -