Radio Astronomy Archives

February 21, 2020February 26, 2020 by Brian Koberlein

How Interferometry Works, and Why it’s so Powerful for Astronomy

Three of the dishes that make up the Atacama Large Millimeter/submillimter Array (ALMA). Image Credit: H. Calderón – ALMA (ESO/NRAO/NAOJ)

When astronomers talk about an optical telescope, they often mention the size of its mirror. That’s because the larger your mirror, the sharper your view of the heavens can be. It’s known as resolving power, and it is due to a property of light known as diffraction. When light passes through an opening, such as the opening of the telescope, it will tend to spread out or diffract. The smaller the opening, the more the light spreads making your image more blurry. This is why larger telescopes can capture a sharper image than smaller ones.

February 12, 2020February 12, 2020 by Evan Gough

A Rare Fast Radio Burst has been Found that Actually Repeats Every 16 Days

Taken with the HAWK-I instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert, this stunning image shows the Milky Way’s central region with an angular resolution of 0.2 arcseconds. This means the level of detail picked up by HAWK-I is roughly equivalent to seeing a football (soccer ball) in Zurich from Munich, where ESO’s headquarters are located. The image combines observations in three different wavelength bands. The team used the broadband filters J (centred at 1250 nanometres, in blue), H (centred at 1635 nanometres, in green), and Ks (centred at 2150 nanometres, in red), to cover the near infrared region of the electromagnetic spectrum. By observing in this range of wavelengths, HAWK-I can peer through the dust, allowing it to see certain stars in the central region of our galaxy that would otherwise be hidden.

A team of scientists in Canada have found a Fast Radio Burst (FRB) that repeats every 16 days. This is in stark contrast to other FRBs, which are more sporadic. Some of those sporadic FRBs occur in clusters, and repeat irregularly, but FRBs with a regular, repeatable occurrence are rare.

January 30, 2020January 30, 2020 by Brian Koberlein

Astronomers See Space Twist Around A White Dwarf 12,000 Light Years Away

A white dwarf and pulsar orbit each other as Parkes observatory watches. Credit: Mark Myers/ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav)

The theory of general relativity is packed with strange predictions about how space and time are affected by massive bodies. Everything from gravitational waves to the lensing of light by dark matter. But one of the oddest predictions is an effect known as frame-dragging. The effect is so subtle it was first measured just a decade ago. Now astronomers have measured the effect around a white dwarf, and it tells us how some supernovae occur.

January 20, 2020January 20, 2020 by Evan Gough

China’s 500-Meter FAST Radio Telescope is Now Operational

The Five-hundred-metre Aperture Spherical Telescope (FAST) has just finished construction in the southwestern province of Guizhou. Credit: FAST

The world’s largest and most sensitive radio telescope is officially open for business according to Xinhua, China’s official state-run media. The FAST Radio Telescope saw fist light in 2016 but has been undergoing testing and commissioning since then. FAST stands for Five-hundred meter Aperture Spherical Telescope.

December 10, 2019December 10, 2019 by Evan Gough

This is the Milky Way’s Magnetic Field

A representation of how our Galaxy would look in the sky if we could see magnetic fields. The plane of the Galaxy runs horizontally through the middle, and the Galactic centre direction is the middle of the map. Red–pink colours show increasing Galactic magnetic field strengths where the direction is pointing towards the Earth. Blue–purple colours show increasing Galactic magnetic field strengths where the direction is pointing away from the Earth. The background shows the signal reconstructed using sources outside our Galaxy. The points show the current measurements for pulsars. The squares show the measurements from this work using LOFAR pulsar observations. Image Credit: Sobey et al, 2019.

The Milky Way galaxy has its own magnetic field. It’s extremely weak compared to Earth’s; thousands of times weaker, in fact. But astronomers want to know more about it because of what it can tell us about star formation, cosmic rays, and a host of other astrophysical processes.

November 30, 2019December 9, 2019 by Matt Williams

There’s Now an Operational Radio Telescope on the Far Side of the Moon

Diagram of the Chang'e-4s mission architecture. Credit: Planetary Society/CSNA-LESEC

The Chang’e-4 mission, the fourth installment in the Chinese Lunar Exploration Program, has made some significant achievements since it launched in December of 2018. In January of 2019, the mission lander and its Yutu 2 (Jade Rabbit 2) rover became the first robotic explorers to achieve a soft landing on the far side of the Moon. Around the same time, it became the first mission to grow plants on the Moon (with mixed results).

In the latest development, the Netherlands-China Low Frequency Explorer (NCLE) commenced operations after a year of orbiting the Moon. This instrument was mounted on the Queqiao communications satellite and consists of three 5-meter (16.4 ft) long monopole antennas that are sensitive to radio frequencies in the 80 kHz – 80 MHz range. With this instrument now active, Chang’e-4 has now entered into the next phase of its mission.

November 28, 2019November 28, 2019 by Evan Gough

Astronomers Are About to Detect the Light from the Very First Stars in the Universe

The Murchison Widefield Array radio telescope in remote Western Australia. Brown University.

A team of scientists working with the Murchison Widefield Array (WMA) radio telescope are trying to find the signal from the Universe’s first stars. Those first stars formed after the Universe’s Dark Ages. To find their first light, the researchers are looking for the signal from neutral hydrogen, the gas that dominated the Universe after the Dark Ages.

August 9, 2019August 9, 2019 by Matt Williams

Dead Planets Around White Dwarfs Could Emit Radio Waves We Can Detect, Sending Out Signals for Billions of Years

Credit: University of Warwick/Mark Garlick

When a star reaches the end of its life cycle, it will blow off its outer layers in a fiery explosion known as a supernova. Where less massive stars are concerned, a white dwarf is what will be left behind. Similarly, any planets that once orbited the star will also have their outer layers blown off by the violent burst, leaving behind the cores behind.

For decades, scientists have been able to detect these planetary remnants by looking for the radio waves that are generated through their interactions with the white dwarf’s magnetic field. According to new research by a pair of researchers, these “radio-loud” planetary cores will continue to broadcast radio signals for up to a billion years after their stars have died, making them detectable from Earth.

June 28, 2019June 28, 2019 by Matt Williams

A Fast Radio Burst has Finally Been Traced Back to its Source: the Outskirts of a Galaxy 4 Billion Light-Years Away

Artist’s impression of CSIRO’s Australian SKA Pathfinder (ASKAP) radio telescope finding a fast radio burst and determining its precise location. The KECK, VLT and Gemini South optical telescopes joined ASKAP with follow-up observations to image the host galaxy. Credit: CSIRO/Dr Andrew Howells

Fast-Radio Bursts (FRBs) are one of the most puzzling phenomena facing astronomers today. Essentially, FRBs are brief radio emissions from distant astronomical sources whose cause remains unknown. In some cases, FRBs that have been detected that have been repeating, but most have been one-off events. And while repeating sources have been tracked back to their point of origin, no single events have ever been localized.

Until now. Using the Australian Square Kilometer Array Pathfinder (ASKAP) and other radio telescopes from around the world, an Australian-led team of astronomers managed to confirm the distance to an intense radio burst that flashed for just a thousandth of a second. The constitutes the first non-repeating FRB to be traced back to its source, which in this case was a galaxy located 4 billion light-years away.

May 10, 2019May 10, 2019 by Matt Williams

A Supercomputer has been Designed to run the World’s Largest Radio Telescope

Artist’s impression of the full Square Kilometre Array at night. Credit: SKA Organisation

When complete, the Square Kilometer Array (SKA) will be the largest radio telescope array in the entire world. The result of decades of work involving 40 institutions in 11 countries, the SKA will allow astronomers to monitor the sky in unprecedented detail and survey it much faster than with any system currently in existence.

Such a large array will naturally be responsible for gathering an unprecedented amount of data on a regular basis. To sort through all this data, the “brain” for this massive array will consist of two supercomputers. Recently, the SKA’s Science Data Processor (SDP) consortium concluded their engineering design work on one of these supercomputers.