4 PI SKY observe the radio counterpart to merging neutron stars

The recent detection of a neutron star-neutron star merger by aLIGO+VIRGO, combined with the associated electromagnetic counterpart have generated a huge amount of excitement in the astrophysical community.


The 4 PI SKY research group has been strongly involved in this, in particular in the radio regime. The JAGWAR project, which led to the discovery of the radio counterpart (arXiv:1710.05435), is led by Kunal Mooley, a member of 4 PI SKY. Kunal and Rob Fender were also involved in observations of the field with MeerKAT (still in commissioning) and Rob was also part of the effort to find a low frequency radio counterpart with LOFAR. Kunal and Rob are furthermore also involved in a project, GWAMI, to try and chase the radio counterparts to future GW events with AMI-LA.



4 Pi Sky VOEvent Broker becomes the standard for rapid-response triggering

Due to the success of the Arcminute Microkelvin Imager Large-Array Rapid-Response Mode (ALARRM) observing program, the 4 Pi Sky VOEvent Broker and the Comet VOEvent client are fast becoming the go-to software standard for receiving, parsing and filtering VOEvent transient alerts. These software allow for the full automation and timely follow-up of transient events using telescopes and facilities with rapid-response observing modes.

Recently the “Radio-Gamma-ray: Transient Alert Mechanisms” meeting was held in Amsterdam (26 – 28 September), in an effort to push for a standardisation of transient astronomy infrastructure and techniques, such as the generation, dissemination, distribution, and reaction to multi-messenger events.

At this meeting, several facilities including the Low Frequency Array (LOFAR), the Australia Telescope Compact Array (ATCA), and the High Energy Stereoscopic System (H.E.S.S) reported they were using Comet and the 4 Pi Sky VOEvent Broker to conduct rapid-response triggering on transient events. The International Virtual Observatory Alliance (IVOA), who manage and edit the VOEvent protocol, recognise both Comet and the 4 Pi Sky VOEvent tools as key software for implementing a VOEvent response network (see slide images below).


Experiments on the Australia Telescope Compact Array, led by Gemma Anderson, use the 4 Pi Sky VOEvent broker to trigger on Swift transient events


Stefan Ohm explains that H.E.S.S. triggers on ASASSN and GAIA transients using the 4 Pi Sky VOEvent broker


Dave Morris at the International Virtual Observatory Alliance (IVOA) mentions that Comet and the 4 Pi Sky VOEvent broker are key software for VOEvent triggering