Due to the coming together of two large groups of astronomers in a new effort, groundbreaking findings about gravity waves, black holes, cosmic rays, neutrinos, and other areas of cutting-edge astronomy may become increasingly common in the near future.
Previously, Europe had two important collaborative networks for ground-based astronomy, known as OPTICON and RadioNet, that had been operating for several decades. These were aimed at observing celestial occurrences in two different wavelength ranges of the electromagnetic spectrum: the first at optical wavelengths, which includes visible light, and the second at longer, radio wavelengths.
The OPTICON RadioNet Pilot (ORP), a consortium of astronomers from 37 institutions and 15 European nations, as well as Australia and South Africa, is bringing these two fields of astronomy together.
The program, which bills itself as “Europe’s largest astronomy network,” was established in response to the growing demand for astronomers to have a diverse set of abilities in many disciplines and to apply complementary methodologies to interpret events. It also brings together approximately 20 telescopes and telescope arrays owned by consortium members, with the goal of harmonizing methodologies and tools across the two domains and allowing physical and virtual access to facilities.
‘There are some people who are experts in both disciplines, but these are different communities,’ said Dr. Jean-Gabriel Cuby, project coordinator for the ORP project at the French National Centre for Scientific Research (CNRS) and Aix-Marseille University. ‘I received my training as an optical astronomer, whereas others received their training as radio astronomers.’ We now need to train wavelength-neutral astronomers as well.’
He stated that the more occurrences you can notice at different wavelengths, the more of a picture you can piece together. ‘Multi-wavelength astronomy is about having as much information as possible by watching throughout the entire spectrum domain,’ he explained. ‘The light we receive in optical and radio wavelengths is produced by many physical processes; so, the more wavelength coverage we observe, the more we understand about the physical processes.’
The goal, according to Dr. Cuby, is to make it easier for individuals to execute more ambitious projects that previously needed large administrative efforts by facilitating and speeding up the process of securing telescope time for projects that require several facilities—which may be a lengthy process.
LOFAR, a trans-European low-frequency radio telescope network established in the Netherlands, and EVN, a network of radio telescopes primarily in Europe and Asia with additional antennas in South Africa and Puerto Rico, are among the telescope facilities.
The age of the multi-messenger
In the age of so-called multi-messenger astronomy, Dr. Cuby emphasized on how the necessity for fostering harmonisation between fields is expanding. This entails the study of a variety of’messenger’ particles, including as gravitational waves, neutrinos, and cosmic rays, which might provide diverse information about the same sources, potentially providing unparalleled insight into the universe and its origins.
Time-domain astronomy, which studies how celestial events change over time, relies heavily on harmony. Many of the events being studied presently are ephemeral, lasting only a few moments, such as quick radio bursts. To capture numerous features of them, rapid deployment of telescopes and facilities is required, which can be facilitated once again through collaboration. ‘In the future years, this time-domain astronomy is going to explode,’ Dr. Cuby predicted. ‘Astronomy is in its golden era right now.’
Professor Gerry Gilmore, a cosmologist at the University of Cambridge who is involved in ORP as scientific coordinator for OPTICON, elaborated further. ‘That’s the kind of science we’re doing now, where you find something that’s generally highly volatile and fleeting,’ he explained. ‘It’s all over in a flash, and you don’t have a second opportunity.’ You want to be able to use all of your prospective powers to stare at that exact spot in the sky right now.’
Previously, Prof. Gilmore explained, recording a fleeting event required a great deal of luck in being in the right place at the right time, but ORP allows researchers to ‘plan to be lucky’ by coordinating their efforts and expanding the ‘discovery space’ in astronomy.
‘As soon as the technology to seek for shorter and shorter timescale events became accessible, we discovered they were all there—the universe is full of stuff.’ And it’s always the most extreme events that occur first.’
Gravitational waves are waves that travel through space.
Much of this multi-messenger and time-domain astronomy is still in its early stages, but technological advancements and fresh deployments of cutting-edge observatories around the world are paving the way.
Gravitational waves are one new field that ORP expects will be aided by collaboration. These are ripples in space-time created by some of the universe’s most cataclysmic events, such as the collision of two black holes, which were first discovered in 2015.
An worldwide team of astronomers announced the discovery of a record number of gravitational waves in November, adding 35 fresh observations in the last six months to bring the total to 90. They hope the discoveries will aid in our knowledge of the evolution of the cosmos and themes such as star birth and death.
With over 1,600 authors from all over the world contributing to the study, which uses around 100 ground- and space-based instruments, including visible, infrared, and radio telescopes, neutrino and gamma-ray observatories, and X-ray instruments, it exemplifies the massive collaboration that is taking place in modern astronomy.
Dr. Sarp Akcay, a theoretical physicist at University College Dublin in Ireland who is not participating in ORP, said one of the authors, who is not involved in ORP, believes the ORP program has the potential to inspire further quick discoveries.
‘This kind of large-scale collaboration will be tremendously beneficial for gravitational-wave astronomy, and much more so for multi-messenger astronomy,’ he said. ‘As more telescopes join a worldwide network, future follow-up observations will be faster, adding to our understanding of these phenomena.’
Prof. Gilmore added that, while the ORP’s main goal is to encourage collaboration rather than conduct specific research, one test case for the project is combining the search for black holes in optical and radio wavelengths to learn more about their nature, how common they are, and whether theories about them are correct.
And with millions of black holes predicted to exist in the Milky Way alone, which are generally produced by the demise of big stars, there’s a lot to learn. Prof. Gilmore explained, “There are a handful of them that have been spotted in very unique situations.” ‘We’ve only seen the tip of the iceberg, but we expect there will be a lot more.’
Long-term perspective
Though ORP, which began in March, is still in its early stages and the exact course of its development is unknown, Dr. Cuby and his colleagues anticipate that the pilot will eventually transform into a long-term project that will last beyond its present deadline of early 2025. The goal is also to provide open access to folks all across the world, allowing previously underrepresented researchers and countries to participate.
Meanwhile, Prof. Gilmore noted that the disparate groups have been rapidly merging in recent years, while the OPTICON and RadioNet initiatives have long created strong collaborative networks in their respective sectors. ‘Over the last few decades, the neighborhood has been progressively transforming,’ he remarked. ‘For a specific scientific issue, people have formed teams and used a variety of facilities. The truth of how we actually do it these days is multi-wavelength astronomy.’
‘Now, a group of young, passionate scientists should be able to choose their leader, she prepares the proposal, and ping—off the team goes,’ he added of the ORP initiative.
Professor Anton Zensus, the ORP project’s scientific coordinator for RadioNet, sees the endeavor as a “crucial step” in advancing the study of astronomy and allowing for a much fuller image of the universe.
‘Using several frequencies allows us to have a greater understanding of the universe’s secrets,’ he said. ‘ORP will enable quick responses to unexpected and fleeting astronomical occurrences in the sky, such as gamma ray bursts. We want to get a whole picture that illuminates all facets of occurrences.’
Dr. Zensus went on to say that bringing the radio and optical communities together to harmonize astronomy is a “critical step” toward making it more appealing to users from all astronomical communities and helping to open up this field of science to non-specialists. ‘A multi-messenger approach will expand our understanding of astronomical events while simultaneously generating new questions and ideas,’ he said.
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