Model-independent measurement of the absolute magnitude of Type Ia supernovae with gravitational-wave sources

Abstract

The similarity of the absolute luminosity profiles of Type Ia supernovae (SNIe), as one kind of distance indicator, has led their use in extragalactic astronomy as secondary standard candles. In general, the empirical relationship of SNIa on the absolute peak magnitude MB is calibrated by Cepheid variables in the near distance scale and directly extrapolated to much farther distances. Therefore, two main problems arise. First of all, their calibration, in particular the determination of MB, depends on the empirical relationship of Cepheid variables, which suffers from various uncertainties. The second is related to the homogeneity of SNIa in their true MB, which is known to be poor in different environments. The observed gravitational-wave (GW) signal of the coalescence of compact binary systems and their electromagnetic counterparts provide the novel and model-independent way to address these two problems. In the era of second-generation GW detectors, the low-redshift GW sources provide a novel method to calibrate the empirical relationship of SNIa, using their self-calibrated distances. In this paper, we use the event GW170817 to calibrate the empirical relationship in different low redshift ranges, and find that the calibration results are consistent with the ones derived from the Cepheid variables. Moreover, the uncertainties of MB in both methods are also comparable. By the observations of third-generation GW detectors, GW sources can also be used to measure the values of MB for the high-redshift SNIe, which provides a unique opportunity to study the dependence of MB on the local environment, strength of gravity, and the intrinsic properties of the explosion, in addition to test the homogeneity of standard candles. We find that the uncertainties of MB in both high and low redshifts are more than one order of magnitude smaller than the current accuracy.