Close look at a local galaxy

NGC 2566

An oval-shaped spiral galaxy, seen close-up. Its core is a compact, pale spot that glows brightly, filling the disc with bluish light. Faint strands of pale reddish dust swirl out from the core to the far sides of the disc. They each join up with an arm of thick, cloudy, red dust with brighter orange patches, that follows the edge of the disc around to the opposite end and a little off the galaxy. ESA/Webb, NASA & CSA, A. Leroy

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The galaxy filling the frame in this NASA/ESA/CSA James Webb Space Telescope Picture of the Month is NGC 2566, a spiral galaxy located in the constellation Puppis. The image combines observations from two of Webb’s instruments, the Near-InfraRed Camera (NIRCam) and Mid-InfraRed Instrument (MIRI), to show off NGC 2566’s well-defined spiral arms, long central bar and delicate tracery of gas, dust and stars.

At 76 million light-years away, NGC 2566 is considered a nearby galaxy, making it an excellent target for studying fine details like star clusters and gas clouds. The new Webb images of NGC 2566 were collected as part of an observing programme (#3707) dedicated to understanding the connections between stars, gas and dust in nearby star-forming galaxies. NGC 2566 is just one of the 55 galaxies in the local Universe examined by Webb for this programme.

The mid-infrared wavelengths captured by MIRI highlight NGC 2566’s warm interstellar dust, including complex, sooty molecules called polycyclic aromatic hydrocarbons. The near-infrared NIRCam data give a detailed view of the galaxy’s stars, even those that are deeply embedded within clouds of gas. The NIRCam data also capture some of the light from the hydrocarbon molecules.

To gain a full understanding of the star-formation process in nearby galaxies, astronomers will combine Webb data with observations from other telescopes. At the long-wavelength end of the electromagnetic spectrum, the 66 radio dishes of the Atacama Large Millimeter/submillimeter Array (ALMA) provide a detailed view of the cold, turbulent clouds where stars are born. The NASA/ESA Hubble Space Telescope has also cast its gaze on NGC 2566, and a new Hubble image of this galaxy was released earlier this week. The Hubble data will help researchers take a census of the stars in nearby galaxies, especially the young stars that are bright at the ultraviolet and visible wavelengths to which Hubble is sensitive. Together, the Webb, Hubble and ALMA data provide a rich view of the cold gas, warm dust and brilliant stars in NGC 2566.

The Webb data are part of a Treasury programme, which means that the data may help answer multiple important questions about our Universe. Treasury data are available for use by scientists and the public without a waiting period, amplifying the scientific impact and allowing exploration to begin immediately.

Source: ESA/Webb/potm

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Links

• Webb's MIRI image of NGC 2566
• Slider Tool: Webb and Hubble's views of NGC 2566
• Pan video: NGC 2566 (Webb NIRCam + MIRI image)
• Pan video: NGC 2566 (Webb MIRI image)
• Transition video: Hubble and Webb's views of NGC 2566

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Astronomers may have discovered the answer to a mysterious stellar event

By using multiple radio telescopes together, the team were able to trace the radio source to a specific object in the sky.
Credit: Hurley-Walker et al.

Researchers from the Curtin node of the International Centre for Radio Astronomy Research (ICRAR) have made a record-breaking astrophysical discovery while simultaneously uncovering a possible explanation for the rare and extreme astrophysical event known as long-period radio transients.

Associate Professor Natasha Hurley-Walker, along with Csanád Horváth, a Curtin undergraduate student at the time, discovered a pulse of bright energy coming from deep space among archival low-frequency data from the MWA (Murchison Widefield Array), a precursor radio telescope to the SKAO (Square Kilometre Array Observatory). The energy pulse occurs every three hours and lasts 30-60 seconds, making this the longest-period radio transient ever detected.

Long-period radio transients are relatively new to science, and it has been an ongoing mystery how they generate radio waves. With this discovery, researchers believe they have also identified the probable source of the energy burst, potentially shedding light on the long radio transients.

All other previously discovered transients have been deep within our busy galaxy, surrounded by stars, making it challenging to determine precisely what is generating the radio waves. Associate Professor Hurley-Walker explains, “The long-period transients are very exciting, and for astronomers to understand what they are, we need an optical image. However, when you look toward them, there are so many stars lying in the way that it’s like 2001: A Space Odyssey. ‘My god, it’s full of stars!’.”

In a stroke of good fortune, the newly discovered transient, named GLEAM-X J0704-37, was found on the outskirts of our galaxy, in a much emptier region of space in the Puppis constellation, around 5000 light years away.

“Our new discovery lies far off the Galactic Plane, so there are only a handful of stars nearby, and we’re now certain one star system, in particular, is generating the radio waves.”

The signal was detected in a less crowded part of the sky, within the constellation Puppis, which allowed the team to pinpoint its source in the sky.

The team was able to pinpoint the location of the radio waves to one specific star using another SKA precursor, the MeerKAT telescope in South Africa. Following up with the SOAR observatory in Chile, they determined the star’s spectrum, finding it was a low-mass star, an ‘M dwarf’.

This finding both created and answered some pressing questions. Associate Professor Hurley-Walker explains, “An M dwarf alone couldn’t generate the amount of energy we’re seeing.

“The M dwarfs are low-mass stars that have a mere fraction of the Sun’s mass and luminosity. They constitute 70 per cent of the stars in the Milky Way, but not one of them is visible to the naked eye.”

“Our data suggests that it is in a binary with another object, which is likely to be a white dwarf, the stellar core of a dying star. Together, they power radio emission.”

Artist’s impression video of the exotic binary star system AR Scorpii

Astronomers have detected similar pairs of objects, like this one discovered in 2016, but had not previously linked them to long period radio transients. Credit: ESO/L. Calçada/University of Warwick

The team is working on follow-up observations that will conclusively determine the nature of the system, and the explanation of this extreme astrophysical event.

Upon digging through the MWA archives, the astronomers found that GLEAM-X J0704-37 has been active for at least ten years since the MWA started observing; however, it could have been active and undiscovered for even longer, implying there are still many more to be found in archives around the world.

MWA Director, Professor Steven Tingay, said, “These long-period radio transients are new scientific discoveries and the MWA has fundamentally enabled the discoveries.” “The MWA has a 55-petabyte archive of observations that provide a decade-long record of our Universe. It is like having the data storage equivalent of 55,000 high-end home computers – one of the biggest single collections of science data in the world. It is an absolute gold mine for discovering more phenomena in our Universe, and the data are a playground for astronomers,” Professor Tingay said.

The research was published overnight in The Astrophysical Journal Letters.

The radio signal was detected in data from the Murchison Widefield Array radio telescope, located at Inyarrimanha Ilgari Bundara, CSIRO’s Murchison Radio-astronomy Observatory. Credit: ICRAR/Curtin

Astronomers find possible cause for mystery signals (vimeo)

Source: International Center for Radio Astronomy Research (ICRAR)/News

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Publication

‘A 2.9-hour periodic radio transient with an optical counterpart’, published in The Astrophysical Journal Letters – November 2024

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Hubble Surveys A Snowman Sculpted from Gas and Dust

 

The Snowman Nebula is an emission nebula that resides in the constellation Puppis in the southern sky, about 6,000 light-years away from Earth. Emission nebulae are diffuse clouds of gas that have become so charged by the energy of nearby massive stars that they glow with their own light. The radiation from these massive stars strips electrons from the nebula’s hydrogen atoms in a process called ionization. As the energized electrons revert from their higher-energy state to a lower-energy state, they emit energy in the form of light, causing the nebula’s gas to glow.

From a telescope on Earth, the Snowman looks a bit like a dual-lobed ball of gas, but this Hubble Space Telescope image captures the details of sweeping curves of bright gas and dark knots of dust in a small section of the nebula. The Snowman is also known as Sharpless 2-302, one of the objects in a catalog of mostly emission nebulae that was compiled by astronomer Stewart Sharpless as he sought to identify areas of interstellar ionized hydrogen, or HII regions.

This image was captured as part of a survey of massive- and intermediate-size “protostars,” or newly forming stars. Astronomers used the infrared sensitivity of Hubble’s Wide Field Camera 3 to look for hydrogen ionized by ultraviolet light from the protostars, jets from the stars, and other features.

The Hubble Space Telescope captured just a small segment of the larger Snowman Nebula. Credits: NASA, ESA, J. Tan (Chalmers University of Technology), and DSS; Processing; Gladys Kober (NASA/Catholic University of America)

Main Image credit: NASA, ESA, and J. Tan (Chalmers University of Technology); Processing; Gladys Kober (NASA/Catholic University of America)

Media Contact:

Claire Andreoli
NASA's Goddard Space Flight Center
301-286-1940

Editor: Andrea Gianopoulos

 

Source: NASA/Hubble

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