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tokens: ). Tanvir et al. ( 2005 ) found a stronger correlation of BATSE SGRBs with early-type than late-type galaxies, which is not expected if nearby SGRBs arise from giant magnetar flares in nearby galaxies, but is consistent with a BNS origin. GRB 170817A is clearly associated with a BNS merger, but even without the connection to GW170817, the spectrum of GRB 170817A in the GBM data strongly disfavored the BB fit expected for a giant magnetar flare. Another possible signature of a giant magnetar flare is the ringing in its tail at the NS period of a few seconds, which could be detected by GBM or by SPI-ACS for flares outside our galaxy providing it was close enough. A search for periodic or quasi-periodic emission in the GBM data for GRB 170817A (Goldstein et al. 2017 ) found no periodic modulation, providing another discriminant between SGRBs and nearby extragalactic giant magnetar flares that might be masquerading as SGRBs. 6.4. Predicted Detection Rates The intrinsic specific volumetric SGRB rate is often quoted to be around 10 Gpc (see, e.g., Guetta Piran 2006 ; Coward et al. 2012 ; Fong et al. 2015 ; with the value originating from Nakar et al. 2006 , who noted that the true rate could be much higher). However, unlike GW signals, SGRBs do not have a clear relationship between the observed distance and brightness. As discussed in the previous section, this can be due to intrinsic variations in SGRB luminosities, as well as structure in the jet. In this Section, we investigate the former scenario presenting the implications of GW170817/GRB 170817A for future GW and SGRB observations in terms of a simple standard model for the SGRB luminosity distribution. Similar interpretations for other, perhaps more elaborate, models are straightforward. We model the SGRB luminosity function as a broken power law, with a logarithmic distribution 186 186 To get the linear distribution of luminosities, both and must be increased by 1. where is the peak isotropic luminosity (in the source frame) between 1 keV and 10 MeV, and and give the power law decay below and above the break at L ⋆ . 187 187 Other studies use a smaller energy band when defining the luminosity, and this has an impact on the value of L ⋆ , although not on the slopes of the power law components. Here, we follow Wanderman Piran ( 2015 ) in using erg s −1 , , and . The other important parameter is the minimum SGRB luminosity, which determines the lower cutoff of the luminosity distribution. This is poorly constrained as only nearby low luminosity SGRBs are observable. In Wanderman Piran ( 2015 ) the minimum luminosity is taken to be erg s −1 , while other studies use values ranging from erg s −1 to erg s −1 (Regimbau et al. 2015 ). We assume a threshold value for detectability in GBM of 2 photons cm −2 s −1 for the 64 ms peak photon flux in the 50–300 keV band, which is higher than the minimum detectability value to account for the sky-dependent sensitivity of GBM. Furthermore, we model the SGRB