Tag: Galaxies

Categories
Universe Today

Scientists confirm that our galaxy’s ‘wave’ is waving

Radcliffe Wave model
This illustration shows how the Radcliffe Wave moves through the backyard of our sun (shown as a yellow dot). The white line represents the wave's current shape and motion. Magenta and green lines show how the wave is expected to move over time. (Credit: Ralf Konietzka, Alyssa Goodman and WorldWide Telescope via CfA)

Astronomers say there’s a wave rippling through our galactic neighborhood that’s playing a part in the birth and death of stars — and perhaps in Earth’s history as well.

The cosmic ripple, known as the Radcliffe Wave, was identified in astronomical data four years ago — but in a follow-up study published today in the journal Nature, a research team lays out fresh evidence that the wave is actually waving, like the wave that fans in a sports stadium create by taking turns standing up and sitting down.

“Similar to how fans in a stadium are being pulled back to their seats by the Earth’s gravity, the Radcliffe Wave oscillates due to the gravity of the Milky Way,” study lead author Ralf Konietzka, a researcher at Harvard and the Harvard-Smithsonian Center for Astrophysics, or CfA, said in a news release.

Continue reading “Scientists confirm that our galaxy’s ‘wave’ is waving”
Categories
GeekWire

Hubble features ghostly galaxy for Halloween

AM 2026-424
This Hubble image of the merged galaxy known as AM 2026-424 was taken on June 19 in visible light by the Advanced Camera for Surveys. The system resides 704 million light-years from Earth. (NASA / ESA / UW / Dalcanton, Williams and Durbin)

Now here’s something really scary for Halloween: Imagine two galaxies slamming into each other and creating a monstrous wraith with ghostly glowing eyes.

It’s not that far of a stretch. The Hubble Space Telescope captured just such an image, for a team of astronomers based at the University of Washington.

The visible-light picture, taken in June by Hubble’s Advanced Camera for Surveys, shows a galactic smash-up that took place about 700 million light-years away in the constellation Microscopium. The cosmic collision is known as Arp-Madore 2026-424 or AM 2026-424, because it’s noted that way in the Arp-Madore Catalogue of Southern Peculiar Galaxies and Associations.

Get the full story on GeekWire.

Categories
GeekWire

Neutrino trackers solve a cosmic ray puzzle

Blazar and neutrino
In this artistic rendering, a blazar is accelerating protons that produce pions, which produce neutrinos and gamma rays. One neutrino’s path is represented by a blue line passing through Antarctica, while a gamma ray’s path is shown in pink. (IceCube / NASA Illustration)

An array of detectors buried under a half-mile-wide stretch of Antarctic ice has traced the path of a single neutrino back to a supermassive black hole in a faraway galaxy, shedding light on a century-old cosmic ray mystery in the process.

The discovery, revealed today in a flurry of research papers published by the journal Science and The Astrophysical Journal, marks a milestone for the IceCube Neutrino Observatory at the National Science Foundation’s Amundsen-Scott South Pole Station.

It also marks a milestone for an observational frontier known as multi-messenger astrophysics, which takes advantage of multiple observatories looking at the sky in different ways. Thanks to IceCube’s alert, more than a dozen telescopes were able to triangulate on the neutrino’s source.

“No one telescope could have done this by themselves,” said IceCube lead scientist Francis Halzen, a physics professor at the University of Wisconsin at Madison.

Get the full story on GeekWire.

Categories
GeekWire

Black holes photobomb Andromeda Galaxy

Black hole pair in Andromeda Galaxy
A combination of X-ray and optical imagery shows the black hole pair known as J0045+41 glowing amid the much closer stars of the Andromeda Galaxy. (X-ray: NASA / CXC / UW / Dorn-Wallenstein et al. Optical: NASA / ESA / J. Dalcanton et al. and R. Gendler)

It turns out that even galaxies can be photobombed.

Imagery from NASA’s Chandra X-ray Observatory and ground-based telescopes reveal what researchers say could be the closest-orbiting pair of supermassive black holes ever seen.

Get the full story on GeekWire.

Categories
GeekWire

Hubble spies galaxies far, far away

Abell 370
A Hubble Space Telescope view shows the Abell 370 galaxy cluster. (NASA / ESA / HST Frontier Fields)

Choose your movie meme: “Guardians of the Galaxy Vol. 2,” or “Star Wars” for May the Fourth. Either way, the Hubble Space Telescope’s newly released picture of the Abell 370 galaxy cluster is just the ticket.

This composite view from Hubble’s Wide Field Camera 3 and the Advanced Camera for Surveys shows hundreds of galaxies in the cluster, which is 6 billion light-years away in the constellation Cetus.

The view is remarkable not only because the galaxies are so dense, but also because their mass serves as a gravitational lens, focusing the light from even more distant galaxies into luminous arcs of blue light.

Get the full story on GeekWire.

Categories
GeekWire

Hubble sees double to mark 27 years in orbit

NGC 4302 and NGC 4298
This Hubble image, marking the 27th anniversary of the space telescope’s launch, features the edge-on spiral galaxy NGC 4302 and the tilted galaxy NGC 4298. (STScI / NASA / ESA Photo / M. Mutchler)

It’s traditional for the team behind the Hubble Space Telescope to release a jaw-dropping picture to celebrate the anniversary of the observatory’s launch in April 1990, and this year’s image might well rate a double jaw drop.

The science team’s greeting card for Hubble’s 27th birthday features side-by-side views of two spiral galaxies much like our own Milky Way galaxy, seen from two angles.

The edge-on galaxy at left, NGC 4302, is about 60 percent of the Milky Way’s size and contains about 10 percent of our home galaxy’s mass, the Hubble team says in today’s image advisory.

The galaxy at right, NGC 4298, is tilted about 70 degrees as seen from Earth, and measures about a third as wide as the Milky Way. It weighs in at 17 billion solar masses, which is less than 2 percent of the Milky Way’s 1 trillion solar masses.

Get the full story on GeekWire.

Categories
GeekWire

Hubble boosts galaxy count by factor of 10

Hubble galaxy survey
A deep-field image from the Great Observatories Origins Deep Survey, or GOODS, shows a scattering of distant galaxies. (Credit: NASA / ESA / GOODS Team / M. Giavialisco / UMass-Amherst)

It looks as if astronomers have been way, way off on their galaxy counts: A new analysis of data from the Hubble Space Telescope suggests that the observable universe holds at least 2 trillion galaxies, which is 10 times the previous estimate.

How could scientists be so far off? The key is that the early universe appears to have had lots of relatively small, faint galaxies. As they merged to form larger galaxies, the population density dwindled.

It took Hubble’s deep-field surveys to register the smaller galaxies that existed far back in time, and it took painstaking analysis to count up a sampling of those galaxies.

Get the full story on GeekWire.

Categories
GeekWire

This galaxy is made of 99.99% dark matter

Image: Dragonfly 44
The dark galaxy Dragonfly 44 appears to have about as much mass as our own Milky Way galaxy, but only 0.01 percent of that mass is in the form of stars and normal matter. The rest is dark matter, scientists say. (Credit: Pieter van Dokkum and Roberto Abraham / Gemini Observatory / AURA)

About 85 percent of the mass of the universe consists of mysterious stuff known as dark matter, but a galaxy called Dragonfly 44 appears to be even darker: 99.99 percent dark, according to newly published findings.

Dragonfly 44, which lies about 300 million light-years away in the Coma galaxy cluster, is the subject of a study published in the Astrophysical Journal Letters.

“It has so few stars that it would quickly be ripped apart unless something was holding it together,” Yale astronomer Pieter van Dokkum, the study’s lead author, said in a news release.

Van Dokkum and his colleagues tracked the motions of the stars in the galaxy using the Keck Observatory and the Gemini North telescope in Hawaii. The stars’ motions told the astronomers about the gravitational field surrounding Dragonfly 44.

Get the full story on GeekWire.