Mittwoch, 7. Dezember 2022 - 07:06

Astronomie - Southern hemispheres biggest radio telescope begins search for ET signatures

5.12.2022

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"One of the first targets we'll be observing is our nearest neighbor star, Proxima Centauri, which appears to host two small rocky planets in the star's habitable zone," said Breakthrough Initiatives Executive Director, Dr. S. Pete Worden. "Routine observations with the Listen backend on MeerKAT are now underway, and the team looks forward to sharing the first science results in the coming months."

Breakthrough Listen has begun observations using a powerful new instrument deployed to the MeerKAT radio telescope in the remote Karoo region of South Africa. The new search for technosignatures - indicators of technology developed by extraterrestrial intelligence - expands the number of targets searched by a factor of 1,000.

The astronomers and engineers on the Breakthrough Listen team have spent the last three years developing and installing the most powerful digital instrumentation ever deployed in the search for technosignatures, and integrating the equipment with the MeerKAT control and monitoring systems in cooperation with SARAO engineers. The new hardware complements Listen's ongoing searches using the Green Bank Telescope in the USA, the Parkes Telescope in Australia, and other telescopes around the world. But while Listen's programs at the GBT and Parkes involve moving these thousand-ton-plus dishes to point at targets all over the sky, the program on MeerKAT usually won't mechanically move the antennas.

"MeerKAT consists of 64 dishes, which can see an area of the sky 50 times bigger than the GBT can view at once," explained Breakthrough Listen Principal Investigator Dr. Andrew Siemion. "Such a large field of view typically contains many stars that are interesting technosignature targets. Our new supercomputer enables us to combine signals from the 64 dishes to get high resolution scans of these targets with excellent sensitivity, all without impacting the research of other astronomers who are using the array."

By operating in this "commensal" mode, Breakthrough Listen gains access to one of the world's most capable and sensitive radio telescopes almost 24 hours a day, 7 days a week. The ability to scan 64 targets at a time within the main field of view also improves Listen's ability to reject interfering signals from human technology such as Earth-orbiting satellites. The Listen team had to develop sophisticated targeting and scheduling software to ensure the survey goals could be met in the desired timeframe 1. They have also developed an automated data processing pipeline that scans through the data in near-real-time to search for interesting signals.

Breakthrough Listen is also working with SARAO to develop research opportunities for astronomers and data processing experts in Africa on this cutting-edge program. The search for life in the Universe has become a major focus area for research internationally, and the Breakthrough Initiatives are leaders in the field.

"I am very excited to be able to conduct a search for technosignatures using one of the most sensitive telescopes in the world," remarked Dr. Cherry Ng, Breakthrough Listen's Project Scientist for MeerKAT. "It will take us just two years to search over one million nearby stars. MeerKAT will provide us with the ability to detect a transmitter akin to Earth's brightest radio beacons out to a distance of 250 light years in our routine observing mode."

Dr. Fernando Camilo, Chief Scientist for SARAO, the observatory that built and operates MeerKAT, is also excited about the new search.

"MeerKAT has a remarkable combination of sensitivity and survey speed, which makes it a wonderful telescope for SETI," said Camilo. "The telescope was planned and developed here in South Africa, and it's very exciting that young South Africans will have the chance to be involved at the forefront of the search for life beyond Earth."

Quelle: SD

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Update: 7.12.2022

‘Great scientific step forward’: Construction of world’s largest radio observatory is finally under way

Two giant telescopes — one in Australia, the other in South Africa — will comprise the supersensitive Square Kilometre Array.

An artists’ impression of SKA-Low antenna arrays.Credit: DISR

After 30 years of planning and negotiations, construction begins this week on the Square Kilometre Array (SKA), the world’s largest radio-astronomy observatory. The giant instrument — to be built across sprawling sites in Australia and Africa — will collect the radio signals emitted by celestial objects and will hopefully shed light on some of the most enigmatic problems in astronomy, such as the nature of dark matter and how galaxies form.

On Monday, astronomers and local communities will travel to the remote sites in South Africa’s Northern Cape and Western Australia to celebrate the milestone with officials from the SKA Observatory (SKAO), the intergovernmental organization in charge of the telescopes.

“We’re basically setting the foundation of this instrument for the next 50 years,” says Lindsay Magnus, the director of the telescope being built in South Africa, who is based in Cape Town, South Africa. “That’s the exciting part — this is a long-term legacy.”

Years in the making

In 2012, it was decided that what had initially been conceived as a single giant telescope would consist of two instruments, one in South Africa and one in Australia. The large distances between antennas, and their sheer number, mean that the telescopes — called SKA-Mid and SKA-Low respectively — will pick up radio signals with unprecedented sensitivity. SKA-Low will detect frequencies between 50 megahertz and 350 megahertz and SKA-Mid will pick up frequencies between 350 megahertz and 15.4 gigahertz. Both are interferometers, in which many dish-shaped antennas together act as a single telescope.

The SKA will be built in stages, and the €1.3-billion (US$1.4-billion) first phase is expected to be completed in 2028. Another €700 million has been earmarked for operation costs for the telescopes over the next decade. The ultimate goal is to have thousands of dishes in South Africa and African partner countries, and one million antennas in Australia, with a total collecting area of one square kilometre. Phase one is about one-tenth of the total planned project.

SKA-Low

The SKA-Low telescope, in Australia, will comprise about 131,000 antennas, each resembling a two-metre-tall wire Christmas trees. More than 500 arrays of 256 antennas will dot the red sands of the site, which has been renamed the Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory. ‘Inyarrimanha Ilgari Bundara’, a name selected by the traditional owners of the land, the Wajarri Yamaji, means ‘Sharing sky and stars’.

Earlier this month, the Wajarri Yamaji and the Australian government registered a land-use agreement that would allow the telescope to be built on Wajarri Yamaji land. Local people will act as heritage monitors and accompany SKAO officials before any ground disturbance throughout construction, says Des Mongoo, a Wajarri Yamatji community member who is looking forward to work beginning. “Once they’ve started construction, there are opportunities for Wajarri people to be involved in employment and commercial opportunities.”

Scientists are also eager for the antennas to start collecting data. “[SKA-Low’s] sensitivity will allow us to observe the distant Universe in much more detail than anything we've done so far,” says Douglas Bock, director of space and astronomy at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Sydney, Australia. “This is particularly exciting because we know so little about the first billion years of the Universe.”

But the most exciting science will be phenomena that “we didn’t even know existed” when the telescopes were designed, predicts SKA-Low telescope director Sarah Pearce, based in Perth. The first four arrays will be collecting data by 2024, with all the arrays completed by 2028.

South Africa’s dishes

On Monday, preparations will also begin for building the first giant SKA-Mid dishes. These will form a collection of 197 antennas, extending over about 150 kilometres in South Africa’s dry Karoo region. Four will be complete in 2024, and many more will be added by 2028.

South Africa’s 64-dish MeerKAT telescope already exists on the site, and will be incorporated into SKA-Mid. In early 2022, using MeerKAT data, an international team published the most detailed image yet of the centre of our galaxy¹, the Milky Way, as well as images of mysterious radio threads emanating from the galaxy’s black hole. The South African government and Germany’s Max Planck Society are adding another 20 dishes to the telescope, as part of an extension project. MeerKAT will be incorporated into SKA-Mid only towards the end of its construction in 2027.

“SKA will be a great scientific step forward,” says Erwin de Blok, an astronomer at the Netherlands Institute of Radio Astronomy in Dwingeloo and a principal investigator on a MeetKAT’s MHONGOOSE large-survey programme looking at galaxy formation. SKA-Mid “will help us study nearby galaxies in great detail and directly detect the flow of gas into galaxies and the processes that lead to star formation”.

However, SKA-Mid’s construction will interfere with MeerKAT observations, says South African Radio Astronomy Observatory director Pontsho Maruping in Cape Town. Radio telescopes are particularly sensitive to the radio waves emitted by vehicles and communications devices. “We're going to do everything we can to make sure that observations don’t get unduly interrupted,” she says. MeerKAT will continue observing until it is incorporated into SKA-Mid in 2027.

By the end of the year, the SKAO, based in the United Kingdom, has awarded €500-million in construction tenders. About 70% of contracts have to go to industry in member countries. There are currently eight full members in the organization — namely Australia, China, Italy, the Netherlands, Portugal, South Africa, Switzerland and the United Kingdom — with France planning to join.

Quelle: nature

Astronomie - Southern hemisphere's biggest radio telescope begins search for ET signatures

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