The effect of environment on type Ia supernovae in the dark energy survey three-year cosmological sample

Kelsey, L, Sullivan, M, Smith, M, Wiseman, P, Brout, D, Davis, T M, Frohmaier, C, Galbany, L, Grayling, M, Gutiérrez, C P, Hinton, S R, Kessler, R, Lidman, C, Wilkinson, R D, Romer, A K, DES Collaboration, and others, (2021) The effect of environment on type Ia supernovae in the dark energy survey three-year cosmological sample. Monthly Notices of the Royal Astronomical Society, 501 (4). pp. 4861-4876. ISSN 0035-8711

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Analyses of type Ia supernovae (SNe Ia) have found puzzling correlations between their standardised luminosities and host galaxy properties: SNe Ia in high-mass, passive hosts appear brighter than those in lower-mass, star-forming hosts. We examine the host galaxies of SNe Ia in the Dark Energy Survey three-year spectroscopically-confirmed cosmological sample, obtaining photometry in a series of ‘local’ apertures centred on the SN, and for the global host galaxy. We study the differences in these host galaxy properties, such as stellar mass and rest-frame U − R colours, and their correlations with SN Ia parameters including Hubble residuals. We find all Hubble residual steps to be >3σ in significance, both for splitting at the traditional environmental property sample median and for the step of maximum significance. For stellar mass, we find a maximal local step of 0.098 ± 0.018 mag; ∼0.03 mag greater than the largest global stellar mass step in our sample (0.070 ± 0.017 mag). When splitting at the sample median, differences between local and global U − R steps are small, both ∼0.08 mag, but are more significant than the global stellar mass step (0.057 ± 0.017 mag). We split the data into sub-samples based on SN Ia light curve parameters: stretch (x1) and colour (c), finding that redder objects (c > 0) have larger Hubble residual steps, for both stellar mass and U − R, for both local and global measurements, of ∼0.14 mag. Additionally, the bluer (star-forming) local environments host a more homogeneous SN Ia sample, with local U − R r.m.s. scatter as low as 0.084 ± 0.017 mag for blue (c < 0) SNe Ia in locally blue U − R environments.

Item Type: Article
Keywords: osmology, observations, distance scale, supernovae, general, surveys, Astrophysics, Cosmology and Nongalactic Astrophysics of Galaxies
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
SWORD Depositor: Mx Elements Account
Depositing User: Mx Elements Account
Date Deposited: 19 Jan 2021 08:35
Last Modified: 31 Aug 2021 09:00

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