Poster Presentation
The influence of the host galaxy morphology on Type Ia Supernova standardization and cosmological analysis
Presenter: Anastasia Baluta (Sternberg Astronomical Institute, Moscow State University)
Standardization of Type Ia Supernovae (SNe Ia) is necessary for a more accurate measurement of the Universe's cosmological parameters using the Hubble diagram. In the SALT2 SN Ia fitting model two standardization parameters of light curves are used: the color parameter c and the stretch parameter x1. In the latest cosmological analyses the dispersion of peak SN brightness is ~0.1 mag after standardization.
However, SN luminosity also depends on its environment. It could be described by different host galaxy characteristics: its morphological type, star formation rate and metallicity, its stellar mass and color. All these parameters correlate and show whether SN Ia exploded in old, passive and metal-poor or in star-forming, young metal-rich environments.
In our work we focus on morphology of host galaxies of SNe Ia and its influence on supernovae standardization. We provide analysis of the Pantheon sample containing 1047 SNe of which 330 SNe have host galaxies with identified morphological types. We work on improving the standardization equation using environmental corrections. Our idea is to examine whether it is reasonable to introduce 2 different standardization equations depending on the environment characteristics: for SNe Ia exploded in early-type galaxies (E-S0/a) and SNe exploded in late-type galaxies (Sa-Sd, Ir).
For this purpose we reproduce the Hubble diagram fit according to the Pantheon analysis and next we perform two separate fits for supernovae in passive and star-forming environments. Then we introduce the host morphology correction and compare the results with the original fit. Our goal is to receive the best results for dispersion of the peak brightness value and thus perform the best standardization for the SNe Ia sample.
asiaa.sinica.edu.tw