Compact Binary Mergers and the Event Rate of Fast Radio Bursts

Fast radio bursts (FRBs) are usually suggested to be associated with mergers of compact binaries consisting of white dwarfs (WDs), neutron stars (NSs), or black holes (BHs). We test these models by fitting the observational distributions in both redshift and isotropic energy of 22 Parkes FRBs, where...

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Bibliographic Details
Published in:The Astrophysical journal 2018-05, Vol.858 (2), p.89
Main Authors: Cao, Xiao-Feng, Yu, Yun-Wei, Zhou, Xia
Format: Article
Language:English
Subjects:
Astrophysics
Binary stars
Black holes
Delay time
Deposition
Electric power distribution
Neutron stars
Power law
Radiation
Radio bursts
radio continuum: general
Red shift
Sky surveys (astronomy)
Star & galaxy formation
Star formation
stars: neutron
Time lag
White dwarf stars
white dwarfs
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Summary:Fast radio bursts (FRBs) are usually suggested to be associated with mergers of compact binaries consisting of white dwarfs (WDs), neutron stars (NSs), or black holes (BHs). We test these models by fitting the observational distributions in both redshift and isotropic energy of 22 Parkes FRBs, where, as usual, the rates of compact binary mergers (CBMs) are connected with cosmic star formation rates by a power-law distributed time delay. It is found that the observational distributions can well be produced by the CBM model with a characteristic delay time from several tens to several hundreds of megayears and an energy function index 1.2 γ 1.7, where a tentative fixed spectral index β = 0.8 is adopted for all FRBs. Correspondingly, the local event rate of FRBs is constrained to for an adopted minimum FRB energy of Emin = 3 × 1039 erg, where fb is the beaming factor of the radiation, is the duration of each pointing observation, and is the sky area of the survey. This event rate, about an order of magnitude higher than the rates of NS-NS/NS-BH mergers, indicates that the most promising origin of FRBs in the CBM scenario could be mergers of WD-WD binaries. Here a massive WD could be produced since no FRB was found to be associated with an SN Ia. Alternatively, if all FRBs can repeat on a timescale much longer than the period of current observations, then they could also originate from a young active NS that forms from relatively rare NS-NS mergers and accretion-induced collapses of WD-WD binaries.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/aabadd