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ZTF SN Ia DR2: Study of Type Ia Supernova lightcurve fits

Fuente: arXiv

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Hauptverfasser:	Rigault, M., Smith, M., Regnault, N., Kenworthy, D. W., Maguire, K., Goobar, A., Dimitriadis, G., Amenouche, M., Aubert, M., Barjou-Delayre, C., Bellm, C. E., Burgaz, U., Carreres, B., Copin, Y., Deckers, M., de Jaeger, T., Dhawan, S., Feinstein, F., Fouchez, D., Galbany, L., Ginolin, M., Graham, J. M., Kim, Y. -L., Kowalski, M., Kuhn, D., Kulkarni, R. S., Muller-Bravo, E. T., Nordin, K., Popovic, M., Purdum, J., Rosnet, P., Rosselli, D., Racine, B., Ruppin, F., Sollerman, J., Terwel, H. J., Townsend, A.
Format:	Preprint
Veröffentlicht:	2024
Schlagworte:	Cosmology and Nongalactic Astrophysics
Online-Zugang:	Acceder al recurso
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author	Rigault, M. Smith, M. Regnault, N. Kenworthy, D. W. Maguire, K. Goobar, A. Dimitriadis, G. Amenouche, M. Aubert, M. Barjou-Delayre, C. Bellm, C. E. Burgaz, U. Carreres, B. Copin, Y. Deckers, M. de Jaeger, T. Dhawan, S. Feinstein, F. Fouchez, D. Galbany, L. Ginolin, M. Graham, J. M. Kim, Y. -L. Kowalski, M. Kuhn, D. Kulkarni, R. S. Muller-Bravo, E. T. Nordin, K. Popovic, M. Purdum, J. Rosnet, P. Rosselli, D. Racine, B. Ruppin, F. Sollerman, J. Terwel, H. J. Townsend, A.
author_facet	Rigault, M. Smith, M. Regnault, N. Kenworthy, D. W. Maguire, K. Goobar, A. Dimitriadis, G. Amenouche, M. Aubert, M. Barjou-Delayre, C. Bellm, C. E. Burgaz, U. Carreres, B. Copin, Y. Deckers, M. de Jaeger, T. Dhawan, S. Feinstein, F. Fouchez, D. Galbany, L. Ginolin, M. Graham, J. M. Kim, Y. -L. Kowalski, M. Kuhn, D. Kulkarni, R. S. Muller-Bravo, E. T. Nordin, K. Popovic, M. Purdum, J. Rosnet, P. Rosselli, D. Racine, B. Ruppin, F. Sollerman, J. Terwel, H. J. Townsend, A.
contents	Type Ia supernova (SN Ia) cosmology relies on the estimation of lightcurve parameters to derive precision distances that leads to the estimation of cosmological parameters. The empirical SALT2 lightcurve modeling that relies on only two parameters, a stretch x1, and a color c, has been used by the community for almost two decades. In this paper we study the ability of the SALT2 model to fit the nearly 3000 cosmology-grade SN Ia lightcurves from the second release of the Zwicky Transient Facility (ZTF) cosmology science working group. While the ZTF data was not used to train SALT2, the algorithm is modeling the ZTF SN Ia optical lightcurves remarkably well, except for lightcurve points prior to -10 d from maximum, where the training critically lacks statistics. We find that the lightcurve fitting is robust against the considered choice of phase-range, but we show the [-10; +40] d range to be optimal in terms of statistics and accuracy. We do not detect any significant features in the lightcurve fit residuals that could be connected to the host environment. Potential systematic population differences related to the SN Ia host properties might thus not be accountable for by the addition of extra lightcurve parameters. However, a small but significant inconsistency between residuals of blue- and red-SN Ia strongly suggests the existence of a phase-dependent color term, with potential implications for the use of SNe Ia in precision cosmology. We thus encourage modellers to explore this avenue and we emphasize the importance that SN Ia cosmology must include a SALT2 retraining to accurately model the lightcurves and avoid biasing the derivation of cosmological parameters.
format	Preprint
id	arxiv_https___arxiv_org_abs_2406_02073
institution	arXiv
publishDate	2024
record_format	arxiv
spellingShingle	ZTF SN Ia DR2: Study of Type Ia Supernova lightcurve fits Rigault, M. Smith, M. Regnault, N. Kenworthy, D. W. Maguire, K. Goobar, A. Dimitriadis, G. Amenouche, M. Aubert, M. Barjou-Delayre, C. Bellm, C. E. Burgaz, U. Carreres, B. Copin, Y. Deckers, M. de Jaeger, T. Dhawan, S. Feinstein, F. Fouchez, D. Galbany, L. Ginolin, M. Graham, J. M. Kim, Y. -L. Kowalski, M. Kuhn, D. Kulkarni, R. S. Muller-Bravo, E. T. Nordin, K. Popovic, M. Purdum, J. Rosnet, P. Rosselli, D. Racine, B. Ruppin, F. Sollerman, J. Terwel, H. J. Townsend, A. Cosmology and Nongalactic Astrophysics Type Ia supernova (SN Ia) cosmology relies on the estimation of lightcurve parameters to derive precision distances that leads to the estimation of cosmological parameters. The empirical SALT2 lightcurve modeling that relies on only two parameters, a stretch x1, and a color c, has been used by the community for almost two decades. In this paper we study the ability of the SALT2 model to fit the nearly 3000 cosmology-grade SN Ia lightcurves from the second release of the Zwicky Transient Facility (ZTF) cosmology science working group. While the ZTF data was not used to train SALT2, the algorithm is modeling the ZTF SN Ia optical lightcurves remarkably well, except for lightcurve points prior to -10 d from maximum, where the training critically lacks statistics. We find that the lightcurve fitting is robust against the considered choice of phase-range, but we show the [-10; +40] d range to be optimal in terms of statistics and accuracy. We do not detect any significant features in the lightcurve fit residuals that could be connected to the host environment. Potential systematic population differences related to the SN Ia host properties might thus not be accountable for by the addition of extra lightcurve parameters. However, a small but significant inconsistency between residuals of blue- and red-SN Ia strongly suggests the existence of a phase-dependent color term, with potential implications for the use of SNe Ia in precision cosmology. We thus encourage modellers to explore this avenue and we emphasize the importance that SN Ia cosmology must include a SALT2 retraining to accurately model the lightcurves and avoid biasing the derivation of cosmological parameters.
title	ZTF SN Ia DR2: Study of Type Ia Supernova lightcurve fits
topic	Cosmology and Nongalactic Astrophysics
url	https://arxiv.org/abs/2406.02073