Modelling the energy distribution in CHIME/FRB Catalog-1

Abstract

We characterize the intrinsic properties of any FRB using its redshift $z$, spectral index $\alpha$ and energy $E_{33}$ in units of $10^{33}\mathrm{J}$ emitted across $2128-2848\mathrm{MHz}$ in the FRB's rest frame. Provided that $z$ is inferred from the measured extra-galactic dispersion measure $D{M}_{\mathrm{Ex}}$, the fluence $F$ of the observed event defines a track in $(\alpha ,E_{33})$ space which we refer to as the "energy track". Here we consider the energy tracks for a sample of $254$ non-repeating low dispersion measure FRBs from the CHIME/FRB Catalog-1, and use these to determine $n(E_{33}\mid \alpha )$ the conditional energy distribution i.e. the number of FRBs in the interval $\Delta E_{33}$ given a value of $\alpha$. Considering $-10\le \alpha \le 10$, we find that the entire energy scale shifts to higher energy values as $\alpha$ is increased. For all values of $\alpha$, we can identify two distinct energy ranges indicating that there are possibly two distinct FRB populations. At high energies, the distribution is well fitted by a modified Schechter function whose slope and characteristic energy both increase with $\alpha$. At low energies, the number of FRBs are in excess of the predictions of the modified Schechter function indicating that we may have a distinctly different population of low-energy FRBs. We have checked that our main findings are reasonably robust to the assumptions regarding the Galactic Halo and Host galaxy contributions to the dispersion measure.

7 pages, 9 figures, Submitted to MNRAS

References in corpus (13)

• A bright millisecond radio burst of extragalactic origin
• Fast Radio Burst Discovered in the Arecibo Pulsar ALFA Survey
• A repeating fast radio burst source localised to a nearby spiral galaxy
• A fast radio burst localised to a massive galaxy
• The Physical Mechanisms of Fast Radio Bursts
• Nine New Repeating Fast Radio Burst Sources from CHIME/FRB
• Probing Galactic Halos with Fast Radio Bursts
• The host galaxies and progenitors of Fast Radio Bursts localized with the Australian Square Kilometre Array Pathfinder
• A Distant Fast Radio Burst Associated to its Host Galaxy with the Very Large Array
• Constraints on the low frequency spectrum of FRB 121102
• A Fast Radio Burst discovered in FAST drift scan survey
• A maximum likelihood estimate of the parameters of the FRB population
• Constraining the Fast Radio Burst (FRB) properties using the joint distributions of dispersion measure and fluence of the events detected at Parkes, ASKAP, CHIME and UTMOST

Cited by in corpus (3)

• Birth and Evolution of Fast Radio Bursts: Strong Population-Based Evidence for a Neutron-Star Origin
• The Cosmic Evolution of Fast Radio Bursts Inferred from the CHIME/FRB Baseband Catalog 1
• Diverse origins for non-repeating fast radio bursts: Rotational radio transient sources and cosmological compact binary merger remnants