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23-04-2021
An Apertif search for radio emission from a double neutron-star merger
| Submitter: | Oliver Boersma |
| Description: | Detection of the electromagnetic emission from coalescing binary neutron stars is important for understanding their properties such as the outflow of material. Electromagnetic follow-up of the gravitational-wave signal coming from such systems has proven difficult due to the often-large error in their localisation. If no counterparts are found at optical or infrared wavelengths, large field-of-view radio telescopes with high sensitivity like Apertif may be the only way to detect any afterglow electromagnetic signal from these events. In our recent paper (arXiv:2104.04280), we present a search for the radio counterpart to the gravitational-wave source GW190425, a binary neutron star merger, using Apertif. In this figure, part of the gravitational-wave localisation sky map on the northern hemisphere for GW190425 is shown. The blue contour encompasses the 50% credible sky area. The inset shows the approximate Apertif field-of-view in yellow, which we observed three times over the course of 41 days. We made use of the LOFAR Transients Pipeline (TraP) to identify all radio sources consistent with the expected afterglow emission of GW190425. We found multiple compatible candidates based on their flux alone. All candidates could be ruled out as the radio source of the afterglow as none could be associated with a possible host galaxy of this particular merger. While we did not find a source related to the emission, the search validates our methods for future searches of radio afterglows and adds to the legacy data of Apertif. Further characterisation and understanding of the Apertif system with ongoing survey operations, and improvements in the imaging pipeline will greatly benefit our search for radio counterparts. Based on additional simulations, we predict that up to three radio afterglows will be detectable by Apertif when the gravitational-wave detectors come online again for their fourth observing run in 2022. |
| Copyright: | N/A |
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