galaxies Archives

December 15, 2020December 15, 2020 by Matthew Cimone

A Galaxy is Making New Stars Faster Than its Black Hole Can Starve Them for Fuel

Computer Simulation of a Quasar, a Supermassive Black Hole that is actively feeding and creating tremendous energy - created in "SpaceEngine" pro by author

A monster lurks at the heart of many galaxies – even our own Milky Way. This monster possesses the mass of millions or billions of Suns. Immense gravity shrouds it within a dark cocoon of space and time – a supermassive black hole. But while hidden in darkness and difficult to observe, black holes can also shine brighter than an entire galaxy. When feeding, these sleeping monsters awaken transforming into a quasar – one of the Universe’s most luminous objects. The energy a quasar radiates into space is so powerful, it can interfere with star formation for thousands of light years across their host galaxies. But one galaxy appears to be winning a struggle against its awoken blazing monster and in a recent paper published in the Astrophysical Journal, astronomers are trying to determine how this galaxy survives.

Animation of Interstellar Matter Falling into a Black Hole Creating a Quasar – ESA

November 17, 2020November 19, 2020 by Paul M. Sutter

The family tree of the Milky Way. The mergers that gave us the galaxy we see today

An edge-on view of a spiral galaxy. Credit: ESO

Galaxies build themselves up slowly over time by cannibalizing their neighbors. Using an advanced suite of computer simulations, researchers have now traced back the evolutionary history of our own Milky Way.

November 3, 2020November 3, 2020 by Evan Gough

The Spherical Structure at the Core of the Milky Way Formed in a Single Burst of Star Formation

This artist’s impression shows how the Milky Way galaxy would look seen from almost edge on and from a very different perspective than we get from the Earth. The central bulge shows up as a peanut shaped glowing ball of stars and the spiral arms and their associated dust clouds form a narrow band. Image Credit: By ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt - http://www.eso.org/public/images/eso1339a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=28256788

Like other spiral galaxies, the Milky Way has a bulging sphere of stars in its center. It’s called “The Bulge,” and it’s roughly 10,000 light-years in radius. Astronomers have debated the bulge’s origins, with some research showing that multiple episodes of star formation created it.

But a new survey with the NOIRLab’s Dark Energy Camera suggests that one single epic burst of star formation created the bulge over 10 billion years ago.

October 30, 2020October 30, 2020 by Evan Gough

Galaxies Grew Quickly and Early On in the Universe

Artist's illustration of a galaxy in the early universe that is very dusty and shows the first signs of a rotationally supported disk. In this image, the red color represents gas, and blue/brown represents dust as seen in radio waves with ALMA. Many other galaxies are visible in the background, based on optical data from VLT and Subaru. Credit: B. Saxton NRAO/AUI/NSF, ESO, NASA/STScI; NAOJ/Subaru

The behaviour of galaxies in the early Universe attracts a lot of attention from researchers. In fact, everything about the early Universe is under intense scientific scrutiny for obvious reasons. But unlike the Universe’s first stars, which have all died long ago, the galaxies we see around us—including our own—have been here since the early days.

Current scientific thinking says that in the early days of the Universe, the galaxies grew slowly, taking billions of years to become what they are now. But new observations show that might not be the case.

October 26, 2020October 26, 2020 by Evan Gough

Astronomers Map Out the Raw Material for New Star Formation in the Milky Way

Accroding to new research, the Milky Way may still bear the marks of "ancient impacts". Credit: NASA/Serge Brunier

A team of researchers has discovered a complex network of filamentary structures in the Milky Way. The structures are made of atomic hydrogen gas. And we all know that stars are made mostly of hydrogen gas.

Not only is all that hydrogen potential future star-stuff, the team found that its filamentary structure is also a historical imprint of some of the goings-on in the Milky Way.

October 7, 2020October 7, 2020 by Evan Gough

7% of the Stars in the Milky Way’s Center Came From a Single Globular Cluster That Got Too Close and Was Broken Up

Central region of the Milky Way in infrared light. With this image, NASA's Spitzer Space Telescope has photographed the inner 890 x 640 light years of the Milky Way. The nuclear star cluster is located in a small area near the central massive black hole. The extended structures in the image are mostly clouds of gas and dust from the spiral arms of the Milky Way, which lie in the line of sight between Earth and the Galactic Centre. Image Credit: NASA/JPL-Caltech/S. Stolovy (Spitzer Science Center/Caltech)

The heart of the Milky Way can be a mysterious place. A gigantic black hole resides there, and it’s surrounded by a retinue of stars that astronomers call a Nuclear Star Cluster (NSC). The NSC is one of the densest populations of stars in the Universe. There are about 20 million stars in the innermost 26 light years of the galaxy.

New research shows that about 7% of the stars in the NSC came from a single source: a globular cluster of stars that fell into the Milky Way between 3 and 5 billion years ago.

September 30, 2020September 30, 2020 by Nancy Atkinson

A Galaxy has been Found That’s as Bright as a Quasar… But it’s Not a Quasar

Image of the region of the sky containing BOSS-EUVLG1 and artist`s drawing of the burst of star formation in BOSS-EUVLG1. Credit: DESI Legacy Imaging Surveys/Gabriel Pérez Díaz, SMM (IAC).

Astronomers have found a new type of galaxy that is very old, very distant and very bright in ultraviolet light. This is somewhat an unusual combination, and so when this bright galaxy was first detected, the team of researchers who found it first thought it was a quasar. But detailed study revealed it was actually a galaxy with some other unusual features, which contributes to its brightness: it is busy with star formation, it has almost no dust.

As of now, this galaxy – with the license plate-type name of BOSS-EUVLG1 – appears to be the only one of its kind.

September 15, 2020September 15, 2020 by Evan Gough

The Milky Way is Already Starting to Digest the Magellanic Clouds, Starting With Their Protective Halos of Hot Gas

A view of the gas in the Magellanic System as it would appear in the night sky. The Magellanic Corona covers the entire sky while the Magellanic Stream is seen as gas flowing away from the two dwarf galaxies, the Large and the Small Magellanic Clouds. This image, taken directly from the numerical simulations, has been modified slightly for aesthetics. Image Credit: COLIN LEGG / SCOTT LUCCHINI

Massive galaxies like our Milky Way gain mass by absorbing smaller galaxies. The Large Magellanic Cloud and the Small Magellanic Cloud are irregular dwarf galaxies that are gravitationally bound to the Milky Way. Both the clouds are distorted by the Milky Way’s gravity, and astronomers think that the Milky Way is in the process of digesting both galaxies.

A new study says that process is already happening, and that the Milky Way is enjoying the Magellanic Clouds’ halos of gas as an appetizer, creating a feature called the Magellanic Stream as it eats. It also explains a 50 year old mystery: Why is the Magellanic Stream so massive?

September 15, 2020September 15, 2020 by Paul M. Sutter

Extreme galaxies depend on extreme conditions for their formation

The spiral pattern shown by the galaxy NGC 2275 in this image from the NASA/ESA Hubble Space Telescope is striking because of its delicate, feathery nature. Credit: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team; Acknowledgment: Judy Schmidt (Geckzilla)

Some galaxies are too small, and some galaxies are too big, while others are just right. A new survey of the nearby Virgo cluster has potentially revealed why extreme galaxies are the wrong size, and how they might be connected.

September 1, 2020September 1, 2020 by Evan Gough

Hubble Shows the True Size of Andromeda

This illustration shows the location of the 43 quasars scientists used to probe Andromeda’s gaseous halo. These quasars—the very distant, brilliant cores of active galaxies powered by black holes—are scattered far behind the halo, allowing scientists to probe multiple regions. Looking through the immense halo at the quasars’ light, the team observed how this light is absorbed by the halo and how that absorption changes in different regions. By tracing the absorption of light coming from the background quasars, scientists are able to probe the halo’s material. Image Credit: NASA, ESA, and E. Wheatley (STScI)

It’s possible that you’ve seen the Andromeda galaxy (M31) without even realizing it. The massive spiral galaxy appears as a grey, spindle-shaped blob in the night sky, visible with the naked eye in the right conditions. It’s the nearest major galaxy to ours, and astronomers have studied it a lot.

Now astronomers have used the Hubble Space Telescope to map out Andromeda’s enormous halo of hot gas.