ZTF SN Ia DR2: Properties of the low-mass host galaxies of Type Ia supernovae in a volume-limited sample

¹ School of Physics, Trinity College Dublin, College Green, Dublin 2, Ireland
² Department of Physics, Lancaster University, Lancs LA1 4YB, UK
³ Oskar Klein Centre, Department of Astronomy, Stockholm University, SE-10691 Stockholm, Sweden
⁴ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona, Spain
⁵ Institut d’Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain
⁶ Univ. Lyon, Univ. Claude Bernard Lyon 1, CNRS, IP2I Lyon/IN2P3, UMR 5822, F-69622 Villeurbanne, France
⁷ Oskar Klein Centre, Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
⁸ National Research Council of Canada, Herzberg Astronomy & Astrophysics Research Centre, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada
⁹ Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany
¹⁰ Université Clermont Auvergne, CNRS/IN2P3, LPCA, F-63000 Clermont-Ferrand, France
¹¹ Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50B-4206, Berkeley, CA 94720, USA
¹² Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720, USA
¹³ Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, ES-38711 Breña Baja, Spain
¹⁴ Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
¹⁵ Caltech Optical Observatories, California Institute of Technology, Pasadena, CA 91125, USA
¹⁶ IPAC, California Institute of Technology, 1200 E. California Blvd Pasadena, CA 91125, USA

^⋆ Corresponding author; burgazu@tcd.ie

Received: 11 October 2024
Accepted: 10 December 2024

Abstract

In this study, we explore the characteristics of ‘low-mass’ (log(M_⋆/M_⊙) ≤ 8) and ‘intermediate-mass’ (8 < log(M_⋆/M_⊙) ≤ 10) host galaxies of Type Ia supernovae (SNe Ia) from the second data release (DR2) of the Zwicky Transient Facility survey. We investigated their correlations with different sub-types of SNe Ia. We used the photospheric velocities measured from the Si IIλ6355 feature, SALT2 light-curve stretch (x₁), and host-galaxy properties of SNe Ia to re-investigate the existing relationship between host galaxy mass and Si IIλ6355 velocities. We also investigated sub-type preferences for host populations. We show that the more energetic and brighter 91T-like SNe Ia tend to reside among the younger host populations, while 91bg-like SNe Ia are found among the older populations. Our findings suggest that high-velocity SNe Ia (HV SNe Ia) do indeed come from older populations, but they can also come from young populations as well. Therefore, while our findings can partly provide support for HV SNe Ia in the context of single degenerate progenitor models, they indicate that HV SNe Ia (rather than comprising a different population) might be a continued distribution with different explosion mechanisms. Lastly, we investigate the specific rate of SNe Ia in the volume-limited SN Ia sample of DR2 and compare our results with other surveys.