ZTF SN Ia DR2: Exploring SN Ia properties in the vicinity of under-dense environments

February 2025 • 2025A&A...694A...7A

Authors • Aubert, M. • Rosnet, P. • Popovic, B. • Ruppin, F. • Smith, M. • Rigault, M. • Dimitriadis, G. • Goobar, A. • Johansson, J. • Barjou-Delayre, C. • Burgaz, U. • Carreres, B. • Feinstein, F. • Fouchez, D. • Galbany, L. • Ginolin, M. • de Jaeger, T. • Kasliwal, M. M. • Kim, Y. -L. • Lacroix, L. • Masci, F. J. • Müller-Bravo, T. E. • Racine, B. • Ravoux, C. • Regnault, N. • Riddle, R. L. • Rosselli, D. • Rusholme, B. • Smith, R. • Sollerman, J. • Terwel, J. H. • Townsend, A.

Abstract • Context. The unprecedented statistics of detected Type Ia supernovae (SNe Ia) brought by the Zwicky Transient Facility (ZTF) enable us to probe the impact of the large-scale structure (LSS) on the properties of these objects. Aims. The goal of this paper is to explore the possible impact of the under-dense part of the LSS on the intrinsic SALT2 light-curve properties of SNe Ia and uncover possible biases in SN Ia analyses. Methods. With a volume-limited selection of ZTF-Cosmo-DR2 SNe Ia overlapping with the SDSS-DR7 survey footprint, we investigated the distribution of their properties with regard to voids detected in the SDSS-DR7 galaxy sample. We further used Voronoi volumes as a proxy for local density environments within the LSS. Results. We find a moderate dependency of the stretch on the localisation around the void centre and none when considering colour. The local Voronoi volumes mostly affect the fraction of low- and high-stretch supernovae. Conclusions. With the presently available statistics, we consider that the impact of high- or low-local-density environment can be considered as a proxy for the colour of the host galaxy. Under-dense environments should not cause any biases in analyses of supernova.

Links

• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361/202450951/postscript
• PDF https://www.aanda.org/10.1051/0004-6361/202450951/pdf
• PREPRINT http://arxiv.org/abs/2406.11680
• ELECTR https://doi.org/10.1051%2F0004-6361%2F202450951