A group of researchers from the Rhodes 老虎机游戏_pt老虎机-平台*官网 Centre for Radio Astronomy Techniques and Technologies (RATT), in partnership with collaborators from the South African Radio Astronomy Observatory (SARAO), Observatoire Paris Meudon, the Breakthrough Listen Initiative, the 老虎机游戏_pt老虎机-平台*官网 of Oxford, the 老虎机游戏_pt老虎机-平台*官网 of Cape Town, and other institutions, have established a project to mine the MeerKAT telescope’s archive for previously overlooked transient radio sources. Their first two finds are being published by Monthly Notices of the Royal Astronomical Society.
MeerKAT’s unique combination of sensitivity and sky coverage enable it to survey the sky with unprecedented speed. This makes the telescope an ideal instrument to search for sources that vary over time, including “transient” sources that appear and disappear suddenly. The telescope is also a powerful tool being used by the Breakthrough Listen Initiative to search for technosignatures, or indicators of technology as a proxy for extraterrestrial intelligence.
The Listen team has deployed dedicated hardware to MeerKAT to search for technosignatures alongside the telescope’s regular observations, but the new partnership is also taking advantage of the large amounts of data already acquired by MeerKAT and stored in its data archive.
“The genesis of this project goes back to our discovery of the RATT PARROT,” explains Distinguished Professor Oleg Smirnov, who leads the Rhodes 老虎机游戏_pt老虎机-平台*官网 team. The PARROT is an unusual pulsar that was serendipitously discovered during processing of completely unrelated observations. “What prompted the discovery in the first place was its transient on/off nature, what we call a ‘transient source’. This brought home the point that many more such transients must be lurking in MeerKAT data – and that it’s the telescope’s exquisite sensitivity that makes it possible to detect them. While dedicated transient search programmes are already being pursued by other groups, we could see a way to start looking for these things semi-automatically, using pretty much any MeerKAT imaging observation – and the archive already has over six years’ worth of observations that can be mined for such exotic transient sources.”
Despite only kicking off the project in March 2024, the team has already had two significant successes.
The first was the detection of a number of millisecond pulsars (MSPs), particularly of the exotic “spider” variety. A spider pulsar revolves around a companion star in such a tight orbit that it “eats away” at it, stripping and accreting matter from the unfortunate companion. This can also cause the pulsar to regularly eclipse, thus manifesting itself as a transient source. Generally, all previously known MSPs pulsars have been detected via dedicated, highly specialised pulsar search observations. This is the first detection of MSPs in routine radio imaging data, which underscores the promise of this technique for finding more of these objects.
The team’s second find was a stellar radio flare. Such events are not unprecedented (after all, we often observe flares from our own Sun), but, owing to the large distances to other stars, remain fairly elusive. This particular star, at over 1300 parsecs away, is no neighbour, so the flare must have been a particularly powerful event to be detectable. The star is of a type called an RS CVn (named after the first such discovered star, RS in the constellation Canum Venaticorum). An RS CVn star also has a binary companion, and events such as flares are presumably due to matter ejected by the companion falling onto the star.
Ironically, the flaring RS CVn was detected in one of the follow-up observations that were done to study the PARROT pulsar. “This reinforces the point that we should be seeing transients everywhere, if we just get smarter at looking for them,” explains Prof. Smirnov. “We found the PARROT through sheer blind luck, then requested a few follow-up observations to get to the bottom of things. Lo and behold, we’ve now caught a flaring star in one of those follow-ups. That’s not luck anymore – that’s the Universe telling us these things are all over the place! And we already have a few more surprises like this in the pipeline –, I’m just not allowed to talk about them yet, but watch this space.“
“The collaboration with our South African colleagues is a great example of the synergies between searches for interesting astrophysical objects, and the search for intelligent life beyond Earth,” explains Dr Ian Heywood, Image Domain Technosignature Lead for the Breakthrough Listen programme at the 老虎机游戏_pt老虎机-平台*官网 of Oxford, and a Visiting Professor at Rhodes 老虎机游戏_pt老虎机-平台*官网. “The Universe has a way of surprising us with the incredible variety of phenomena that arise as a result of the basic laws of physics. And if the same processes that gave rise to intelligent life and technology on Earth also operate elsewhere, instruments like MeerKAT provide our best chance to date of finding our cosmic neighbours.”
Contacts & More Info
Prof Oleg Smirnov, Rhodes Centre for Radio Astronomy Techniques & Technologies (RATT) Email: o.smirnov@ru.ac.za
The Rhodes Centre for Radio Astronomy Techniques & Technologies (RATT) was established in 2012 around the eponymous SKA (SARChI) Research Chair awarded to Rhodes 老虎机游戏_pt老虎机-平台*官网. RATT’s mission is to conduct world-class research into novel radio astronomy calibration, imaging, data analysis algorithms, software and techniques that are urgently required to maximize the science yield of the next generation of radio telescopes such as MeerKAT and the Square Kilometre Array (SKA). In 2023, RATT was honoured to receive the prestigious NRF Science Team award.
Website: https://ratt.center
The South African Radio Astronomy Observatory (SARAO) is a national facility of the National Research Foundation (NRF) and responsible for implementing South Africa’s strategic investment in radio astronomy, including leading South Africa’s involvement in the international Square Kilometre Array (SKA) project on behalf of the Department of Science, Technology and Innovation (DSTI). Its tasks include the development and operations of the state-of-the-art MeerKAT radio telescope in the Karoo and the geodesy and VLBI activities at the Hartebeesthoek Radio Astronomy Observatory (HartRAO). SARAO also implements the Africa Programme, which includes coordination of the African VLBI Network (AVN) for the eight SKA partner countries in Africa (Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia, and Zambia), as well as South Africa’s contribution to the infrastructure and engineering planning and construction for the SKA radio telescope.,
Website: https://sarao.ac.za
Breakthrough Listen, headquartered at the 老虎机游戏_pt老虎机-平台*官网 of Oxford, is the world’s most comprehensive search for “technosignatures”, or signs of intelligent life in the Universe. Listen collaborates with facilities around the globe, including many of the most powerful radio telescopes, as well as cutting-edge observatories operating in other regions of the electromagnetic spectrum. It is surveying one million nearby stars, the entire galactic plane and 100 nearby galaxies.
Website: breakthroughinitiatives.org
Founded in 1667, the Paris Observatory is one of the oldest astronomical institutions in the world. Since the mid-20th century, it has been involved in radio astronomy, pioneering research and instrumentation. In the past decade, in partnership with RATT, Paris Observatory has played a leading role developing algorithms that aim at obtaining high quality images with modern radio interferometers. These advancements have been critical to the success of the large radio surveys and are laying the groundwork for the upcoming SKA. Recently, an innovative technique has been developed in Paris to generate high resolution dynamic spectra (see figures below). This capability allows us to systematically monitor millions of nearby stellar systems, with the aim of searching for star-planet interactions, exoplanetary radio emissions, and other faint astrophysical signatures such as the ones detected in this study.
Website: https://observatoiredeparis.psl.eu/
A MeerKAT image of a part of the PARROT field, showing the flaring RS CVn star (circled).
A “dynamic spectrum” of the millisecond pulsar PSR J1748-2446A, showing its emission as a function of time and frequency. The eclipsing behaviour is clear from the alternating bands of high and low flux.
A “dynamic spectrum” of the flare from the RS CVn star.