5 years ago

GRB170817A: a giant flare from a jet-less double neutron-star merger?.

Gabriele Ghisellini, Monica Colpi, Giancarlo Ghirlanda, Om S. Salafia

We show that GRB170817A and the subsequent radio and X-ray observations can be interpreted as due to an isotropic fireball loaded with a small amount ($M\sim 3\times 10^{-6}\,{\rm M_\odot}$) of neutron-rich ($Y_{\rm e}\sim 0.06$) material, which expands relativistically reaching a Lorentz factor $\Gamma\sim 5$. The physical picture resembles that of a giant flare from a magnetar, and could have been driven by an ultra-strong magnetic field $B\sim 3\times 10^{16}\,{\rm G}$ produced through amplification by magnetohydrodynamic turbulence at the beginning of the merger phase of the progenitor double neutron-star binary. Within such picture, the X-ray and radio data indicate a very tenuous ($n\sim 10^{-5}\,{\rm cm^{-3}}$) circum-binary medium, suggesting that the binary was outside the host galaxy in our direction, or that some process has blown a cavity around the binary before the merger. No relativistic jet is needed to explain the observations published in the literature so far, but we show that future radio and X-ray observations can be used to rule out the proposed picture. If our interpretation turns out to be correct, it indicates that not all double neutron-star mergers produce a jet, while most should feature this isotropic, hard X-ray component that can be a powerful guide to the discovery of additional kilonovae associated to relatively nearby gravitational wave events.

Publisher URL: http://arxiv.org/abs/1711.03112

DOI: arXiv:1711.03112v1

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.