Prospects of Searching for Type Ia Supernovae with 2.5-m Wide Field Survey Telescope

Abstract

Type Ia supernovae (SNe Ia) are thermonuclear explosions of carbon-oxygen white dwarfs (WDs) and are well-known as a distance indicator. However, it is still unclear how WDs increase their mass near the Chandrasekhar limit and how the thermonuclear runaway happens. The observational clues associated with these open questions, such as the photometric data within hours to days since the explosion, are scarce. Thus, an essential way is to discover SNe Ia at specific epochs with optimal surveys. The 2.5 m Wide Field Survey Telescope (WFST) is an upcoming survey facility deployed in western China. In this paper, we assess the detectability of SNe Ia with mock observations of the WFST. Followed by the volumetric rate, we generate a spectral series of SNe Ia based on a data-based model and introduce the line-of-sight extinction to calculate the brightness from the observer. By comparing with the detection limit of the WFST, which is affected by the observing conditions, we can count the number of SNe Ia discovered by mock WFST observations. We expect that the WFST can find more than 3.0×104 pre-maximum SNe Ia within one year of running. In particular, the WFST could discover about 45 bright SNe Ia, 99 early phase SNe Ia, or 1.1×104 well-observed SNe Ia with the hypothesized Wide, Deep, or Medium modes, respectively, suggesting that the WFST will be an influential facility in time-domain astronomy.

Limiting Magnitudes of the Wide Field Survey Telescope (WFST)

“…The estimated WFST limiting redshift of Type Ia supernovae (SNe Ia) can reach z ∼ 0.64 (luminosity distance ∼6.3 × 10 3 Mpc) and z ∼ 1.67 (∼1.2 × 10 4 Mpc) when the exposure time is 30 s and 100 × 30 s. SNe Ia can be used to constrain the dark energy in the universe (Riess et al 1998) and directly measure the Hubble constant (Riess et al 2022). By simulating observations of the SNe Ia with the WFST at the Lenghu site, Hu et al (2022) estimate that above 10 4 pre-maximum SNe Ia will be discovered in one-year during the wide or deep observations, which suggests that WFST will be a powerful facility in revealing the physics of SNe Ia. Lin et al (2022) computed the prospects of finding Tidal Disruption Events (TDEs) with the WFST.…”