The luminosity–volume test for cosmological Fast Radio Bursts. (arXiv:1811.10641v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Locatelli_N/0/1/0/all/0/1">Nicola Locatelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ronchi_M/0/1/0/all/0/1">Michele Ronchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ghirlanda_G/0/1/0/all/0/1">Giancarlo Ghirlanda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ghisellini_G/0/1/0/all/0/1">Gabriele Ghisellini</a>
We perform the luminosity–volume test, also known as $langle
V/V_{MAX}rangle$, to Fast Radio Bursts (FRBs). We compare the 23 FRBs,
recently discovered by ASKAP, with 20 of the FRBs found by Parkes. These
samples have different flux limits and correspond to different explored
volumes. We assume that their dispersion measure indicates their redshift and
apply the appropriate cosmological corrections to the spectrum and rate in
order to compute the $langle V/V_{MAX}rangle$ for the ASKAP and Parkes
samples. For a radio spectrum of FRBs $F_nu propto nu^{-1.6}$, we find
$langle V/V_{MAX}rangle=0.66pm 0.05$ for the ASKAP sample, that includes
FRBs up to $z=0.7$, and 0.52$pm 0.04$ for Parkes, that extends up to $z=2.1$.
The ASKAP value suggests that the population of FRB progenitors evolves faster
than the star formation rate, while the Parkes value is consistent with it.
Even a delayed (as a power law or gaussian) star formation rate cannot
reproduce the $langle V/V_{MAX}rangle$ of both samples. If FRBs do not evolve
in luminosity, the $langle V/V_{MAX}rangle$ values of ASKAP and Parkes sample
are consistent with a population of progenitors whose density strongly evolves
with redshift as $sim z^{2.8}$ up to $z sim 0.7$. We discuss possible
scenarios accounting for our results.
We perform the luminosity–volume test, also known as $langle
V/V_{MAX}rangle$, to Fast Radio Bursts (FRBs). We compare the 23 FRBs,
recently discovered by ASKAP, with 20 of the FRBs found by Parkes. These
samples have different flux limits and correspond to different explored
volumes. We assume that their dispersion measure indicates their redshift and
apply the appropriate cosmological corrections to the spectrum and rate in
order to compute the $langle V/V_{MAX}rangle$ for the ASKAP and Parkes
samples. For a radio spectrum of FRBs $F_nu propto nu^{-1.6}$, we find
$langle V/V_{MAX}rangle=0.66pm 0.05$ for the ASKAP sample, that includes
FRBs up to $z=0.7$, and 0.52$pm 0.04$ for Parkes, that extends up to $z=2.1$.
The ASKAP value suggests that the population of FRB progenitors evolves faster
than the star formation rate, while the Parkes value is consistent with it.
Even a delayed (as a power law or gaussian) star formation rate cannot
reproduce the $langle V/V_{MAX}rangle$ of both samples. If FRBs do not evolve
in luminosity, the $langle V/V_{MAX}rangle$ values of ASKAP and Parkes sample
are consistent with a population of progenitors whose density strongly evolves
with redshift as $sim z^{2.8}$ up to $z sim 0.7$. We discuss possible
scenarios accounting for our results.
http://arxiv.org/icons/sfx.gif
