Early color photometry of a possible type Iax supernova 2023mnc: inferring the distance and progenitor constraints

Abstract

Early-time radioactive signals from type Ia supernovae (SNeIa) can provide important constraints on the explosion mechanism and the progenitor system. We present observations and analysis of SN 2023mnc, a SN Ia, $\sim 7$ days following its discovery. Follow-up observations were conducted in optical bands, covering phases from $\sim -4$ days to $\sim 15$ days relative to its r-band peak luminosity. The early photometry allows us to estimate the physical properties of the ejecta and characterize the possible divergence from a normal SN Ia; we were able to characterize it as a Type Iax supernova instead. The estimated date of explosion is $t_{0}=60130$ MJD and implies a short rise time of $t_{rise} \approx 16$ days. The apparent g-band peak magnitude and the post-peak decline rate are $m_{max}(g)=-19.52\pm 0.47$ mag and $\Delta m_{15}(g)=0.825\pm 1.635$ mag, respectively. Based on the light curve fitting of standard SN Ia models, the distance modulus is predicted to be $37.98\pm 0.207$ mag for g-band measurements, and the SN is predicted to be $394.46\pm 38$ Mpc from Earth. Assuming a ⁵⁶Ni powered radiative diffusion, the estimated bolometric light-curve peaks at $3.8 \times 10^{41}$ erg s⁻¹ and indicates that only $0.017 M_{\odot }$ of ⁵⁶Ni was produced, making SN 2023mnc a moderate luminosity object in the Iax class with peak absolute magnitude of $M_{V}=-15.3$ mag. Comparing the observed color evolution with the predicted by different models such as deflagration-to-detonation transition and pure-deflagration scenario, the latter one is favored. The photometry of SN 2023mnc offers a unique opportunity to examine the progenitor systems and ignition process of the SNe Iax, adding weight to the population study of such sub-class SNe.

Appendix: Observational data

Table 1 Photometric Standards in the SN 2023mnc Field for Sloan g-r bands

Table 2 Ground-based Optical Photometry of SN 2023mnc

Table 3 Transformation Coefficients for Photometry of SN 2023mnc

Table 4 Chi-squared values for model supernova light curves fitted to Sloan g and r light curves of SN 2023mnc