ABSTRACT Fast radio bursts (FRBs) are extremely powerful sources of radio waves observed at cosmological distances. We use a sophisticated model of FRB observations – presented in detail in a companion paper – to fit FRB population parameters using large samples of FRBs detected by ASKAP and Parkes, including seven sources with confirmed host galaxies. Our fitted parameters demonstrate that the FRB population evolves with redshift in a manner consistent with, or faster than, the star formation rate (SFR), ruling out a non-evolving population at better than 98 per cent CL (depending on modelling uncertainties). Our estimated maximum FRB energy is $\log _{10} E_{\rm max} [{\rm erg}] = 41.70_{-0.06}^{+0.53}$ (68 per cent CL) assuming a 1 GHz emission bandwidth, with slope of the cumulative luminosity distribution $\gamma =-1.09_{-0.10}^{+0.14}$. We find a log-mean host DM contribution of $129_{-48}^{+66}$ pc cm−3 on top of a typical local (interstellar medium and halo) contribution of ∼80 pc cm−3, which is higher than most literature values. These results are insensitive to assumptions of the FRB spectral index, and are consistent with the model of FRBs arising as the high-energy limit of magnetar bursts, but allow for FRB progenitors that evolve faster than the SFR.
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Exploring the epoch of hydrogen reionization using FRBs
ABSTRACT We describe three different methods for exploring the hydrogen reionization epoch using fast radio bursts (FRBs) and provide arguments for the existence of FRBs at high redshift (z). The simplest way, observationally, is to determine the maximum dispersion measure (DMmax) of FRBs for an ensemble that includes bursts during the reionization. The DMmax provides information regarding reionization much like the optical depth of the cosmic microwave background to Thomson scattering does, and it has the potential to be more accurate than constraints from Planck, if DMmax can be measured to a precision better than 500 pccm−3. Another method is to measure redshifts of about 40 FRBs between z of 6 and 10 with ${\sim}10{{\ \rm per\ cent}}$ accuracy to obtain the average electron density in four different z-bins with ${\sim}4{{\ \rm per\ cent}}$ accuracy. These two methods do not require knowledge of the FRB luminosity function and its possible redshift evolution. Finally, we show that the reionization history is reflected in the number of FRBs per unit DM, given a fluence limited survey of FRBs that includes bursts during the reionization epoch; we show using FIRE simulations that the contribution to DM from the FRB host galaxy and circumgalactic medium during the reionization era is a small fraction of the observed DM. This third method requires no redshift information but does require knowledge of the FRB luminosity function.
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- NSF-PAR ID:
- 10269533
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 502
- Issue:
- 4
- ISSN:
- 0035-8711
- Page Range / eLocation ID:
- 5134 to 5146
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/mnras/stab309
