AT 2017gfo: An Anisotropic and Three-component Kilonova Counterpart of GW170817

By Albino Perego, David Radice, Sebastiano Bernuzzi. 2017

196 citations recorded by the source corpus.

The detection of a kilo/macronova electromagnetic counterpart (AT 2017gfo) of the first gravitational-wave signal compatible with the merger of two neutron stars (GW170817) has confirmed the occurrence of r-process nucleosynthesis in this kind of event. The blue and red components of AT 2017gfo have been interpreted as the signature of multi-component ejecta in the merger dynamics. However, the explanation of AT 2017gfo in terms of the properties of the ejecta and of the ejection mechanisms is still incomplete. In this work, we analyze AT 2017gfo with a new semi-analytic model of kilo/macronova inferred from general-relativistic simulations of the merger and long-term numerical models of the merger aftermath. The model accounts for the anisotropic emission from the three known mass ejecta components: dynamic, winds, and secular outflows from the disk. The early multi-band light curves of AT 2017gfo can only be explained by the presence of a relatively low-opacity component of the ejecta at high latitudes. This points to the key role of weak interactions in setting the ejecta properties and determining the nucleosynthetic yields. Our model also constrains the total ejected mass associated to AT 2017gfo to be between 0.042 and 0.077 , the observation angle of the source to be between and , and the mass of the disk to be .

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/bf5cc8ab85fa815c60733abb96d2a2f843008fb3

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In Astronomy and Astrophysics

Citations in the corpus

A Magnetar Origin for the Kilonova Ejecta in GW170817 (2018, background): “…these give best-fit values for the ejecta masses and mean velocities of the blue and red components of M M v c2 10 , 0.25blue 2 blue» ´ »- and Mred≈0.05Me, vred≈0.1 c, respectively (e.g., Cowperthwaite et al. 2017; Drout et al. 2017; Kasen et al. 2017; Perego et al. 2017; Villar et al. 2017).”
Constraints on the neutron star equation of state from AT2017gfo using radiative transfer simulations (2018, result): “Qualitatively, similar results were seen in other studies using 2D models (Wollaeger et al. 2018), and in semianalytical models that explicitly take into account the non-spherical character of the ejecta (Perego et al. 2017).”
The Origin of r-process Elements in the Milky Way (2017, methodology): “For better agreement with observations, some studies argued that an additional third ejecta component is required, such as a wide-angle mildly relativistic cocoon (Kasliwal et al. 2017b), secular disk winds (Perego et al. 2017) or a “purple kilonova” outflow (Cowperthwaite et al. 2017).”
Binary Neutron Star Mergers: Mass Ejection, Electromagnetic Counterparts, and Nucleosynthesis (2018, methodology): “This is expected to emit a large amount of neutrinos over the diffusion timescale (a few seconds; e.g., Dessart et al. 2009; Perego et al. 2017b).”
GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations (2017, background): “In these cases, neutrino driven winds and viscous and magnetic processes in the disk are expected to unbind sufficient material to explain the optical and infrared observations for AT2017gfo (Perego et al. 2014; Wu et al. 2016; Siegel & Metzger 2017).”