An international team of more than 200 astronomers from 18 countries has published the first phase of a major new radio sky survey at unprecedented sensitivity using the Low Frequency Array (LOFAR) telescope. The survey reveals hundreds of thousands of previously undetected galaxies, shedding new light on many research areas including the physics of black holes and how clusters of galaxies evolve. A special issue of the scientific journal Astronomy & Astrophysics is dedicated to the first twenty-six research papers describing the survey and its first results.
Radio astronomy reveals processes in the Universe that we cannot see with optical instruments. In this first part of the sky survey, LOFAR observed a quarter of the northern hemisphere at low radio frequencies. At this point, approximately ten percent of that data is now made public. It maps three hundred thousand sources, almost all of which are galaxies in the distant Universe; their radio signals have travelled billions of light years before reaching Earth.
Huub Röttgering, Leiden University (The Netherlands): "If we take a radio telescope and we look up at the sky, we see mainly emission from the immediate environment of massive black holes. With LOFAR we hope to answer the fascinating question: where do those black holes come from?" What we do know is that black holes are pretty messy eaters. When gas falls onto them they emit jets of material that can be seen at radio wavelengths.
Philip Best, University of Edinburgh (UK), adds: "LOFAR has a remarkable sensitivity and that allows us to see that these jets are present in all of the most massive galaxies, which means that their black holes never stop eating."
-=- Posted: Thursday 15 November 2018 -=-
‘Close encounters of the Birr kind …’
The inspiration for this headline from the Irish Daily Mail came of course from the famous science fiction movie ‘Close encounters of the third kind’ – about our meeting with an alien civilization. The occasion was the inauguration of a new radio telescope on the outskirts of the large park around Birr Castle, Ireland.
Birr is a relatively small town in Ireland, almost a village, located a few hundred kilometres west of Dublin. And Birr Castle has roots dating back to the Middle Ages.
The new radio telescope, bearing the name I LOFAR, was inaugurated in the very same park where the Third Earl of Rosse built the largest astronomical telescope in the world in 1845.
The new radio telescope is just the latest contribution to what is the largest network of radio telescopes in the world, called ‘The International LOFAR Telescope,' which is headquartered in the Netherlands.
The network is distributed around Europe with 38 antenna stations in the Netherlands, six in Germany, three in Poland, and single antennas in France, Sweden, and England.
Read the full article by clicking here.
-=- Posted: Tuesday 17 July 2018 (an article by Liam Mannix in The Age-Sunday Extra 14th July 2018) -=-
Due to copyright requirements I can only provide a link to this excellent article.
-=- Posted: Monday 2 July 2018 -=-
In an important engineering milestone, a full station of 256 low-frequency antennas has been deployed and is undergoing tests at CSIRO’s Murchison Radio-astronomy Observatory (MRO) in outback Western Australia.
The demonstrator, known as the Aperture Array Verification System (AAVS1) is being used to help test and finalise the design of the low frequency antennas for the Square Kilometre Array (SKA), known as SKA-low.
It was installed by an international team from Australia, Italy, Malta, the Netherlands and the United Kingdom over many months, sometimes in harsh conditions.
“This is a significant achievement by the team, they have done a fantastic job. We have been thinking, discussing and designing together for several years. Putting together and testing this verification system has been an amazing experience.” said AAVS1 Project Manager Pieter Benthem. Benthem is based at the Netherlands Institute for Radio Astronomy (ASTRON), the institute that leads the consortium working on the design of the SKA-low telescope.
The work is part of a global effort by 12 international engineering consortia representing 500 engineers and scientists in 20 countries.
Nine of the consortia focus on a component of the telescope, each critical to the overall success of the project, while three others focus on developing advanced instrumentation for the telescope.
After four years of intense design work, the nine consortia are having their Critical Design Review or CDR in 2018.
In this final stage, the proposed design must meet the project’s tough engineering requirements to be approved, so that a construction proposal for the telescope can be developed.
The consortium focusing on SKA-low is now working towards its critical design review later this year.
“There’s still a lot of work to be done, but the lessons we’ve learnt from AAVS1 will be fed into the larger design process for SKA-low” said ICRAR Associate Professor Randall Wayth.
“The antennas used for AAVS1 are what we call second generation prototypes. The tests now being conducted on them are helping predict how the fourth generation will behave. It’s all about making sure we get the best possible hardware on site at the end” explains Phil Gibbs, SKA Organisation’s Project Manager for the consortium.
“The next steps will be to complete the tests, interpret the results so they can feed into the proposed design for the SKA low telescope and prepare for the critical design review, which is anticipated to take place later this year” he added.
For the teams that have been involved in the work, seeing a completed prototype on site in the Australian outback is a great achievement after many years of work.
“This is the first time that I’m involved in such a big project, so for me it’s a great experience” said Marco Poloni, an engineer from INAF in Italy who has been part of the installation campaign.
AAVS1 is in the process of being connected to the Murchison Widefield Array (MWA), one of the four SKA precursor telescopes, which has been operational since 2013. By combining the data of the demonstrator with the MWA, the engineers will be able to fully characterise its on-sky performance.
Both AAVS1 and MWA have been heavily supported by scientists, engineers and data-intensive astronomy specialists from the International Centre for Radio Astronomy Research (ICRAR) in Perth, Western Australia.
-=- Posted: Saturday 16 June 2018 -=-
Two independent teams of astronomers have uncovered convincing evidence that three young planets are in orbit around an infant star known as HD 163296. Using a new planet-finding strategy, the astronomers identified three discrete disturbances in a young star’s gas-filled disk: the strongest evidence yet that newly formed planets are in orbit there.
Over the past several years, the Atacama Large Millimeter/submillimeter Array (ALMA) has transformed our understanding of protoplanetary disks - the gas and dust-filled planet factories that encircle young stars. The rings and gaps in these disks provide intriguing circumstantial evidence for the presence of planets. Other phenomena, however, could account for these tantalizing features.
Using a new planet-hunting technique that identifies unusual patterns in the flow of gas within a protoplanetary disk, two teams of astronomers have confirmed the distinct, telltale hallmarks of newly formed planets orbiting an infant star in our galaxy. These results are presented in a pair of papers appearing in the Astrophysical Journal Letters.
“We looked at the localized, small-scale motion of gas in a star’s protoplanetary disk. This entirely new approach could uncover some of the youngest planets in our galaxy, all thanks to the high-resolution images coming from ALMA,” said Richard Teague, an astronomer at the University of Michigan and principal author on one of the papers.
To make their respective discoveries, each team analyzed the data from various ALMA observations of the young star HD 163296. HD 163296 is about 4 million years old and located about 330 light-years from Earth in the direction of the constellation Sagittarius.
Rather than focusing on the dust within the disk, which was clearly imaged in an earlier ALMA observation, the astronomers instead studied the distribution and motion of carbon monoxide (CO) gas throughout the disk. Molecules of CO naturally emit a very distinctive millimeter-wavelength light that ALMA can observe. Subtle changes in the wavelength of this light due to the Doppler effect provide a glimpse into the kinematics – or motion – of the gas in the disk.
If there were no planets, gas would move around a star in a very simple, predictable pattern known as Keplerian rotation.
“It would take a relatively massive object, like a planet, to create localized disturbances in this otherwise orderly motion,” said Christophe Pinte of Monash University in Australia and lead author on one of the two papers. “Our new technique applies this principle to help us understand how planetary systems form.”
-=- Posted: Sunday 20 May 2018 -=-
Not long after the Big Bang, the first generations of stars began altering the chemical make-up of primitive galaxies, slowly enriching the interstellar medium with basic elements such as oxygen, carbon, and nitrogen. Finding the earliest traces of these common elements would shed important light on the chemical evolution of galaxies, including our own.
New observations with the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the faint, telltale signature of oxygen coming from a galaxy at a record-setting distance of 13.28 billion light-years from Earth, meaning we are observing this object it as it appeared when the universe was only 500 million years old, or less than 4 percent its current age.
For such a young galaxy, known as MACS1149-JD1, to contain detectable traces of oxygen, it must have begun forging stars even earlier: a scant 250 million years after the Big Bang. This is exceptionally early in the history of the universe and suggests that rich chemical environments evolved quickly.
-=- Posted: Saturday 28 April 2018 -=-
An article published today in The Astrophysical Journal presents the study of a magnetar – a star that is one of the most magnetic objects known in the universe – that awoke in 2017 from a 3-year slumber. Radio observations that could only be made with MeerKAT, a telescope being built in the Northern Cape province of South Africa, triggered observations with NASA X-ray telescopes orbiting the Earth. This first publication in the scientific literature of astronomical discoveries requiring the use of MeerKAT heralds its arrival into the stable of world-class research instruments.
Dr Fernando Camilo, Chief Scientist at the South African Radio Astronomy Observatory (SARAO, which includes the Square Kilometre Array South Africa project), describes the setting one year ago: “On 26 April 2017, while monitoring the long-dormant magnetar with the CSIRO Parkes Radio Telescope in Australia, one of our colleagues noticed that it was emitting bright radio pulses every 4 seconds”. A few days later Parkes underwent a planned month-long maintenance shutdown. Although MeerKAT was still under construction, with no more than 16 of its eventual 64 radio dishes available, the commissioning team started regular monitoring of the star 30,000 light years from Earth. According to Camilo, “the MeerKAT observations proved critical to make sense of the few X-ray photons we captured with NASA’s orbiting telescopes – for the first time X-ray pulses have been detected from this star, every 4 seconds. Put together, the observations reported today help us to develop a better picture of the behaviour of matter in unbelievably extreme physical conditions, completely unlike any that can be experienced on Earth”.
-=- Posted: Monday 16 April 2018 -=-
The recent visit to our Solar System by the cometary fragment known as 'Oumuamua late last year proved to be very interesting. Rather than being spherical it was a long slender object about 4 kilometers in length. Its reflectivity was quite low indicating it was made of dark material and likely had no icy structure.
The ability of the Murchison Widefield Array radio telescope to view a large area of the sky and its large frequency coverage meant there was a possibility of detecting radio transmissions that might have come from 'Oumuamua. A paper was written detailing the examination of recorded data from the MWA during the time that 'Oumuamua was in range of Earth. Click here for the pdf of the publication.
-=- Posted: Wednesday 3 January 2018 -=-
While not strictly 'News', I found a great little Youtube video of a visit to one of the dishes at Kitt Peak that make up the Very Long Baseline Array.
-=- Posted: Friday 22 December 2017 -=-
We received a lovely Christmas message from the SKA Organisation reprinted as follows;
As 2017 comes to an end we can look back on a busy but productive year across the Square Kilometre Array project.
You can read all about recent developments from across the project in the latest edition of our newsletter, as well as news from the central Office in the latest edition of the SKAO Bulletin, our bi-monthly project update from the SKA Headquarters at Jodrell Bank, UK - seen above a few days ago after some heavy snow!
This is also an opportunity to mention we are currently recruiting for several roles within the SKA Office, which you can view here. I would encourage you to apply or distribute them within your professional networks.
Finally, I also invite you to read two feature stories we published earlier this week on some of the design activities for the two SKA telescopes. In addition to providing insights into the technical complexities, logistics and practical challenges of bringing together hardware coming from different parts of the world, this two-part series truly reflects the international nature of these two particular elements, and more generally of our project.
From lab to Outback: The story of AAVS1 so far covers some of the developments towards the SKA1-low telescope in Australia and Across 18 time zones: a global effort to deliver a dish prototype covers some of the developments towards SKA1-mid in South Africa.
2018, I am sure, will be an exciting and, as always, eventful year for the SKA.
I wish you season’s greetings and thank you for your continued support.
Prof. Philip Diamond
SKA Organisation Director-General
-=- Posted: Tuesday 28 November 2017 -=-
From an article in the Sydney Morning Herald 'The Milky Way has to eat galaxies to keep building stars. Our galaxy needs food, and these are kind of snacks'. Professor McClure-Griffiths and her team are interested in how galaxies form, and how they die. The best way to find that out, they say, is to follow the hydrogen. Hydrogen fuels stars and is the basic building block of all galaxies. Inside a galaxy it swirls around until it is compressed by gravity into a new star. A galaxy that has a lot of hydrogen can make new stars and expand in size. The team is studying the Small Magellanic Cloud, a dwarf galaxy that orbits the Milky Way. The Cloud has several hundred million stars – a small fry compared to the Milky Way's hundreds of billions.
-=- Posted: Thursday 23 November 2017 -=-
On Tuesday 21st November, our 36th PAF was installed on AK #29 marking the completion of installation of all receivers for ASKAP-36! Earlier this month, our last PAF (PAF # 40 – our second spare PAF), passed functional and EMI testing signifying the end of the PAF production testing at Marsfield. By the end of the month we will also be shipping the Jodrell Bank PAF to UK to complete our contract with Jodrell Bank Observatory (after having completed our Max Plank Institute contract in 2016). All of these milestones are very significant not just for all of the team members who have worked very hard for a number of years to bring this to fruition, but I am sure also for all of CASS and for its stakeholders awaiting this momentous occasion for some time.
There is no better way to finish off 2017. - Thanks again and Happy 36th!