paper

Cosmology-independent estimate of the fraction of baryon mass in the IGM from fast radio burst observations

arXiv:1904.08927 · doi:10.3847/1538-4357/ab18fe

Abstract

The excessive dispersion measure (DM) of fast radio bursts (FRBs) has been proposed to be a powerful tool to study intergalactic medium (IGM) and to perform cosmography. One issue is that the fraction of baryons in the IGM, , is not properly constrained. Here we propose a method of estimating using a putative sample of FRBs with the measurements of both DM and luminosity distance . The latter can be obtained if the FRB is associated with a distance indicator (e.g. a gamma-ray burst or a gravitational wave event), or the redshift of the FRB is measured and at the corresponding is available from other distance indicators (e.g. type Ia supernovae) at the same redshift. Since essentially does not depend on cosmological parameters, our method can determine independent of cosmological parameters. We parameterize as a function of redshift and model the DM contribution from a host galaxy as a function of star formation rate. Assuming has a mild evolution with redshift with a functional form and by means of Monte Carlo simulations, we show that an unbiased and cosmology-independent estimate of the present value of with a uncertainty can be obtained with 50 joint measurements of and DM. In addition, such a method can also lead to a measurement of the mean value of DM contributed from the local host galaxy.

6 pages, 5 figures, to appear in ApJ

References in corpus (18)

Cited by in corpus (37)