galaxies Archives

February 25, 2023February 25, 2023 by Carolyn Collins Petersen

A New Survey of the Sky Contains Over One Billion Galaxies

Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. The image is teeming with galaxies — in fact, nearly every single object in this image is a galaxy. Some exceptions include a couple of dozen asteroids as well as a few handfuls of foreground stars in our own Milky Way. Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA Acknowledgments: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), J. Miller, M. Zamani & D. de Martin (NSF’s NOIRLab) — Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during its survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. Nearly every single object in this image is a galaxy. Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA Acknowledgments: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), J. Miller, M. Zamani & D. de Martin (NSF’s NOIRLab)

What contains a petabyte of data on more than a billion galaxies in one of the most extensive sky maps? The answer: the ever-expanding Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Survey. The galaxies it charts are part of the largest two-dimensional map of the sky ever made. And, just recently, it grew even larger with the addition of new data from telescopes in the U.S. and Chile.

February 23, 2023February 24, 2023 by Nancy Atkinson

“The Universe Breakers”: Six Galaxies That are Too Big, Too Early

Images of six candidate massive galaxies, seen 500-700 million years after the Big Bang. One of the sources (bottom left) could contain as many stars as our present-day Milky Way, according to researchers, but it is 30 times more compact. Credit: NASA, ESA, CSA, I. Labbe (Swinburne University of Technology). Image processing: G. Brammer (Niels Bohr Institute’s Cosmic Dawn Center at the University of Copenhagen).

In the first data taken last summer with the Near Infrared Camera (NIRCam) on the new James Webb Space Telescope, astronomers found six galaxies from a time when the Universe was only 3% of its current age, just 500-700 million years after the Big Bang. While its incredible JWST saw these galaxies from so long ago, the data also pose a mystery.

These galaxies should be mere infants, but instead they resemble galaxies of today, containing 100 times more stellar mass than astronomers were expecting to see so soon after the beginning of the Universe. If confirmed, this finding calls into question the current thinking of galaxy formation and challenges most models of cosmology.

February 17, 2023February 17, 2023 by Evan Gough

Galaxies Aren’t Just Stars. They’re Intricate Networks of Gas and Dust

This image taken by the NASA/ESA/CSA James Webb Space Telescope shows the spiral galaxy NGC 1433. Image Credit: NASA, ESA, CSA, and J. Lee (NOIRLab), A. Pagan (STScI)

Astronomers have studied the star formation process for decades. As we get more and more capable telescopes, the intricate details of one of nature’s most fascinating processes become clearer. The earliest stages of star formation happen inside a dense veil of gas and dust that stymies our observations.

But the James Webb Space Telescope sees right through the veil in its images of nearby galaxies.

February 15, 2023February 15, 2023 by Evan Gough

A Galaxy has Been Found that’s Almost Entirely Dark Matter

This is the galaxy Dragonfly 44, which is an Ultra Diffuse Galaxy (UDG.) It's about as massive as the Milky Way, but only 1% as luminous. Astronomers think it's almost entirely made of dark matter. Now scientists have found another one like it. Image Credit: By Teymursaif - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=95121595

Astronomers have discovered a galaxy with very little or no stellar mass. Galaxies like these are called ‘dark galaxies.’ It contains clouds of gas but very few stars, possibly none. This is the only isolated dark dwarf galaxy in the local universe.

February 14, 2023February 14, 2023 by Evan Gough

Astronomers Spot a Rogue Supermassive Black Hole, Hurtling Through Space Leaving Star Formation in its Wake

This artist's conception illustrates a supermassive black hole (central black dot) at the core of a young, star-rich galaxy. Now astronomers have found a rogue SMBH travelling through space. Image credit: NASA/JPL-Caltech

Supermassive black holes (SMBHs) lurk in the center of large galaxies like ours. From their commanding position in the galaxy’s heart, they feed on gas, dust, stars, and anything else that strays too close, growing more massive as time passes. But in rare circumstances, an SMBH can be forced out of its position and hurtle through space as a rogue SMBH.

February 13, 2023February 13, 2023 by Evan Gough

Globular Star Clusters are Constantly Kicking Stars out of the Galaxy

Omega Centauri is the brightest globular cluster in the night sky. It holds about 10 million stars and is the most massive globular cluster in the Milky Way. It's possible that globulars and nuclear star clusters are related in some way as a galaxy evolves. Image Credit: ESO.

All the stars we can see with the naked eye are part of the Milky Way. The gravitational power of the galaxy’s combined mass binds the stars to the galaxy. But sometimes stars are evicted from the galaxy.

These stars are called hypervelocity stars, and some of them are born from powerful gravitational interactions in globular clusters.

February 13, 2023February 13, 2023 by Evan Gough

Astronomers Uncover Mass Migration of Stars into Andromeda

Astronomers at NSF’s NOIRLab found new evidence for a mass immigration of stars into the Andromeda Galaxy. This image shows individual stars from blue (moving toward us) to red (moving away from us). Image Credit: KPNO/NOIRLab/AURA/NSF/E. Slawik/D. de Martin/M. Zamani

Astronomers know that galaxies grow over time through mergers with other galaxies. We can see it happening in our galaxy. The Milky Way is slowly absorbing the Large and Small Magellanic Clouds and the Sagittarius Dwarf Spheroidal Galaxy.

For the first time, astronomers have found evidence of an ancient mass migration of stars into another galaxy. They spotted over 7,000 stars in Andromeda (M31), our nearest neighbour, that merged into the galaxy about two billion years ago.

February 9, 2023February 9, 2023 by Carolyn Collins Petersen

Seeing a Mirror Image of the Milky Way From Billions of Years Ago

An artist's impression of our Milky Way Galaxy in its youth, with satellite galaxies and clusters. The newly found Sparkler Galaxy shows similar activity. Credit: James Josephides, Swinburne University. CC BY 4.0.

Ever wonder what our Milky Way Galaxy looked like in its early history? Astronomers using the Webb Telescope (JWST) found another galaxy that’s almost a mirror image of our galaxy as an infant. It’s nicknamed “The Sparkler”. That’s because it has about two dozen glittering globular clusters orbiting around it. There are also a few dwarf galaxies there, being swallowed up by the galaxy.

February 6, 2023February 6, 2023 by Carolyn Collins Petersen

Face-on View of Galaxy NGC 4303 Reveals its Arms are Filled with Active Star Formation

NGC 4303, a galaxy rich in star formation. It lies about 55 million light-years away in the Virgo Cluster. This view shows both visible-light and millimeter-wavelength views of the galaxy. Credit: ESO/ALMA (ESO/NAOJ/NRAO)/PHANGS

Galaxies fill a lot of roles in the universe. The most obvious one is star formation factories. Without that activity, the cosmos would be a very different place. The European Southern Observatory and the Atacama Large Millimeter Array recently zeroed in on the galaxy NGC 4303. Their goal: to take a multi-wavelength view of its star formation activity.

January 26, 2023January 26, 2023 by Evan Gough

Astronomers Pin Down the Age of the Most Distant Galaxy: Seen 367 Million Years After the Big Bang

The radio telescope array ALMA has pin-pointed the exact cosmic age of a distant JWST-identified galaxy, GHZ2/GLASS-z12, at 367 million years after the Big Bang. Image Credit: NASA / ESA / CSA / T. Treu, UCLA / NAOJ / T. Bakx, Nagoya U. Licence type Attribution (CC BY 4.0)

Staring off into the ancient past with a $10 billion space telescope, hoping to find extraordinarily faint signals from the earliest galaxies, might seem like a forlorn task. But it’s only forlorn if we don’t find any. Now that the James Webb Space Telescope has found those signals, the exercise has moved from forlorn to hopeful.

But only if astronomers can confirm the signals.