Fast radio bursts (FRBs), a promising new and mysterious astrophysical phenomenon, are a class of bright transients with millisecond durations detected at ∼GHz (Lorimer et al. 2007; Keane et al. 2011; Thornton et al. 2013; Burke-Spolaor & Bannister 2014; Spitler et al. 2014; Masui & Sigurdson 2015; Petroff et al. 2015, 2016; Ravi et al. 2015, 2016; Champion et al. 2016; Keane et al. 2016; Caleb et al. 2017). Although the physical origin of these intense short pulses has not been figured out so far, most of them have been detected with relatively large dispersion measures (DM) (greater than the maximum produced by the Milky Way). This suggests that they may occur at a cosmological distance, probably at distances of the order of gigaparsecs (Ioka 2003; Inoue 2004; Deng & Zhang 2014; Zheng et al. 2014; Zhang 2018). So far, the cosmological origin of these kinds of mysterious flashes has been confirmed by successfully localizing several bursts (including two repeaters and several apparently nonrepeating ones; Spitler et al. 2016; Scholz et al. 2016; Chatterjee et al. 2017; Marcote et al. 2017; Tendulkar et al. 2017; Bannister et al. 2019; Prochaska et al. 2019; Ravi et al. 2019; Wang & Zhang 2019; Zhang & Wang 2019; Marcote et al. 2020). The confirmation of their cosmological origin allows them to be widely proposed as promising tools for studying the universe and fundamental physics, e.g., the distribution of baryons in the intergalactic medium (IGM) or diffuse gas (Deng & Zhang 2014; Mcquinn 2014; Muñoz & Loeb 2018; Li et al. 2019, 2020; Walters et al. 2019; Wei et al. 2019; Macquart et al. 2020), dark energy (Gao et al. 2014; Zhou et al. 2014; Walters et al. 2018; Wei et al. 2018; Zhao et al. 2020), cosmic ionization history (Deng & Zhang 2014; Zheng et al. 2014), the large-scale structure of the universe (Masui & Sigurdson 2015), the Einstein’s equivalence principle (Wei et al. 2015; Nusser 2016; Tingay & Kaplan 2016), the rest mass of the photon (Wu et al. 2016; Shao & Zhang 2017; Xing et al. 2019), the cosmic proper distance measurements (Yu & Wang 2017), and constraints on the magnetic fields in the IGM (Akahori et al. 2016), as well as measuring the cosmic expansion rate (Wu et al. 2020). Because the event rate of this phenomenon inferred from observations is very high (∼103–104 per day all sky; Thornton et al. 2013; Champion et al. 2016) and due to their extragalactic origin, these bursts are likely to be gravitationally lensed by intervening objects with a different magnitude of mass. Moreover, high time resolutions or short durations of these bursts (∼(1–10) ms) (Lorimer et al. 2007; Keane et al. 2011; Thornton et al. 2013; Spitler et al. 2014, 2016; Petroff et al. 2015, 2016; Ravi et al. 2015; Champion et al. 2016) guarantee that the difference between arrival times of two images can be resolved even if they are lensed by an object as small as 10  M⊙. Therefore, different scale lensing effects of FRBs have been proposed as a probe of compact dark matter (Muñoz et al. 2016; Wang & Wang 2018; Liao et al. 2020; Ranjan 2020), motion of the FRB source (Dai & Lu 2017), and precision cosmology (Li et al. 2018; Liu et al. 2019; Wucknitz et al. 2020). Recently, taking into consideration the theoretical prediction that a portion of FRBs might be associated with GWs, Wei et al. (2018) proposed the joint measurements of DM from FRB observations and DL from GW detections in the same FRB/GW association system (i.e., the combination DM · DL as a function of redshift) as a complementary cosmic probe. The most striking merit of this probe is the independence of the Hubble constant H0, which is a fundamental cosmological parameter now under intense debate because of the well-known Hubble constant tension (Planck Collaboration et al. 2018; Riess et al. 2019). In this paper, we propose that the combination DM · DL as a function of redshift could be further extended to the independent measurements of DMs of localized FRBs and DL of other distance indicators (e.g., SNe Ia) at a similar redshift according to the fundamental assumption that luminosity distance monotonously increases with increasing redshift. Following Masui & Sigurdson (2015), who call brief broadband radio impulses like FRBs “standard pings,” the extended combination DM · DL as a function of redshift can be easily constructed from independent measurements of standard pings and standard candles at similar redshifts (Wei et al. 2018). Moreover, in the CPL framework, we investigate the constraining power on the equation of state of dark energy from this extended combination.
Citation: Li et al.; 2020
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