Jump to content

Hubble Pinpoints a Dim, Starry Mini-galaxy


NASA

Recommended Posts

  • Publishers
Several stars shine against black space. A few foreground stars with diffraction spikes throughout.
The Pegasus Dwarf spheroidal galaxy, also known as Andromeda VI, is one of at least 13 dwarf galaxies that orbit the Andromeda galaxy.
NASA, ESA, and D. Weisz (University of California – Berkeley); Processing: Gladys Kober (NASA/Catholic University of America)

A glittering collection of stars shines against a background of much more distant galaxies in this view from NASA’s Hubble Space Telescope of the Pegasus Dwarf spheroidal galaxy, also known as Andromeda VI. 

The Andromeda galaxy, also known as Messier 31, is the Milky Way’s closest grand spiral galaxy neighbor, and is host to at least 13 dwarf galaxies that orbit around it. The Pegasus Dwarf spheroidal galaxy is one of these mini-galaxies. Dwarf spheroidal galaxies are the dimmest and least massive galaxies known. They tend to have elliptical shapes and relatively smooth distributions of stars. Dwarf spheroidal galaxies are usually devoid of gas and dominated by old and intermediate-age stars, although some have experienced small amounts of recent star formation. 

The Pegasus Dwarf Spheroidal galaxy was discovered in 1998 and has been characterized as having a small amount of heavy elements and little of the gas needed  to form another generation of stars ― though more than many of the dwarf spheroidal galaxies within our Local Group of galaxies. Researchers suspect that Andromeda’s gravitational field may have stripped the star-forming gases from it, leaving a dearth of material to build more than a few generations of stars. In comparison, some of the dwarf spheroidal companion galaxies of the Milky Way found at comparable distances do contain some intermediate-age stars, but this could be because Andromeda is so massive and extended that its gravitational effects extend farther. 

The jury is still out on how dwarf spheroidal galaxies form. Theories include collisions between galaxies that break off small fragments, the gravitational influence of larger galaxies on small disk-shaped dwarf galaxies, and processes associated with the birth of small systems among collections of dark matter. Andromeda and the Milky Way are the only galaxies close enough for astronomers to view these dim satellite galaxies, so clues to their formation will have to come from close neighbors like this one.

Hubble studied this galaxy as part of an examination of the entire Andromeda system of satellites in order to investigate such critical matters as dark matter, reionization, and the growth of galactic ecosystems across cosmic time.

Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight CenterGreenbelt, MD
claire.andreoli@nasa.gov

View the full article

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By NASA
      Artists Concept of the WASP-77 A b system. A planet swings in front of its star, dimming the starlight we see. Events like these, called transits, provide us with bounties of information about exoplanets–planets around stars other than the Sun. But predicting when these special events occur can be challenging…unless you have help from volunteers.
      Luckily, a collaboration of multiple teams of amateur planet-chasers, led by researcher Federico R. Noguer from Arizona State University and researchers from NASA’s Jet Propulsion Laboratory (JPL) and Goddard Space Flight Center (GSFC), has taken up the challenge. This collaboration has published the most precise physical and orbital parameters to date for an important exoplanet called WASP-77 A b.  These precise parameters help us predict future transit events and are crucial for planning spacecraft observations and accurate atmospheric modeling. 
      “As a retired dentist and now citizen scientist for Exoplanet Watch, research opportunities like this give me a way to learn and contribute to this amazingly exciting field of astrophysics,” said Anthony Norris, a citizen scientist working on the NASA-funded Exoplanet Watch project.
      The study combined amateur astronomy/citizen science data from the Exoplanet Watch and ExoClock projects, as well as the Exoplanet Transit Database. It also incorporated data from NASA’s Spitzer Space Telescope, the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), and La Silla Observatory. Exoplanet Watch invites volunteers to participate in groundbreaking exoplanet research, using their own telescopes to observe exoplanets or by analyzing data others have gathered. You may have read another recent article about how the Exoplanet Watch team helped validate a new exoplanet candidate.
      WASP-77 A b is a gas giant exoplanet that orbits a Sun-like star. It’s only about 20% larger than Jupiter. But that’s where the similarities to our solar system end. This blazing hot gas ball orbits right next to its star–more than 200 times closer to its star than our Jupiter!
      Want a piece of the action? Join the Exoplanet Watch project and help contribute to cutting-edge exoplanet science! Anyone can participate–participation does not require citizenship in any particular country.
      Facebook logo @DoNASAScience @DoNASAScience Share








      Details
      Last Updated Sep 19, 2024 Related Terms
      Astrophysics Citizen Science Exoplanet Science Explore More
      4 min read NASA’s Webb Provides Another Look Into Galactic Collisions


      Article


      1 day ago
      4 min read NASA’s Hubble Finds More Black Holes than Expected in the Early Universe


      Article


      2 days ago
      2 min read Hubble Examines a Spiral Star Factory


      Article


      6 days ago
      View the full article
    • By NASA
      ESA/Hubble & NASA, M. Koss, A, Barth This NASA/ESA Hubble Space Telescope image features the spiral galaxy IC 4709 located around 240 million light-years away in the southern constellation Telescopium. Hubble beautifully captures its faint halo and swirling disk filled with stars and dust bands. The compact region at its core might be the most remarkable sight. It holds an active galactic nucleus (AGN).
      If IC 4709’s core just held stars, it wouldn’t be nearly as bright. Instead, it hosts a gargantuan black hole, 65 million times more massive than our Sun. A disk of gas spirals around and eventually into this black hole, crashing together and heating up as it spins. It reaches such high temperatures that it emits vast quantities of electromagnetic radiation, from infrared to visible to ultraviolet light and X-rays. A lane of dark dust, just visible at the center of the galaxy in the image above, obscures the AGN in IC 4709. The dust lane blocks any visible light emission from the nucleus itself. Hubble’s spectacular resolution, however, gives astronomers a detailed view of the interaction between the quite small AGN and its host galaxy. This is essential to understanding supermassive black holes in galaxies much more distant than IC 4709, where resolving such fine details is not possible.
      This image incorporates data from two Hubble surveys of nearby AGNs originally identified by NASA’s Swift telescope. There are plans for Swift to collect new data on these galaxies. Swift houses three multiwavelength telescopes, collecting data in visible, ultraviolet, X-ray, and gamma-ray light. Its X-ray component will allow SWIFT to directly see the X-rays from IC 4709’s AGN breaking through the obscuring dust. ESA’s Euclid telescope — currently surveying the dark universe in optical and infrared light — will also image IC 4709 and other local AGNs. Their data, along with Hubble’s, provides astronomers with complementary views across the electromagnetic spectrum. Such views are key to fully research and better understand black holes and their influence on their host galaxies.
      View the full article
    • By NASA
      Hubble Space Telescope Home NASA’s Hubble Finds More… Missions Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities   4 Min Read NASA’s Hubble Finds More Black Holes than Expected in the Early Universe
      The Hubble Ultra Deep Field of nearly 10,000 galaxies is the deepest visible-light image of the cosmos. The image required 800 exposures taken over 400 Hubble orbits around Earth. The total amount of exposure time was 11.3 days, taken between Sept. 24, 2003 and Jan. 16, 2004. Credits:
      NASA, ESA, S. Beckwith (STScI) and the HUDF Team With the help of NASA’s Hubble Space Telescope, an international team of researchers led by scientists in the Department of Astronomy at Stockholm University has found more black holes in the early universe than has previously been reported. The new result can help scientists understand how supermassive black holes were created.
      Currently, scientists do not have a complete picture of how the first black holes formed not long after the big bang. It is known that supermassive black holes, that can weigh more than a billion suns, exist at the center of several galaxies less than a billion years after the big bang.
      “Many of these objects seem to be more massive than we originally thought they could be at such early times — either they formed very massive or they grew extremely quickly,” said Alice Young, a PhD student from Stockholm University and co-author of the study  published in The Astrophysical Journal Letters.
      This is a new image of the Hubble Ultra Deep Field. The first deep imaging of the field was done with Hubble in 2004. The same survey field was observed again by Hubble several years later, and was then reimaged in 2023. By comparing Hubble Wide Field Camera 3 near-infrared exposures taken in 2009, 2012, and 2023, astronomers found evidence for flickering supermassive black holes in the hearts of early galaxies. One example is seen as a bright object in the inset. Some supermassive black holes do not swallow surrounding material constantly, but in fits and bursts, making their brightness flicker. This can be detected by comparing Hubble Ultra Deep Field frames taken at different epochs. The survey found more black holes than predicted. NASA, ESA, Matthew Hayes (Stockholm University); Acknowledgment: Steven V.W. Beckwith (UC Berkeley), Garth Illingworth (UC Santa Cruz), Richard Ellis (UCL); Image Processing: Joseph DePasquale (STScI)
      Download this image

      Black holes play an important role in the lifecycle of all galaxies, but there are major uncertainties in our understanding of how galaxies evolve. In order to gain a complete picture of the link between galaxy and black hole evolution, the researchers used Hubble to survey how many black holes exist among a population of faint galaxies when the universe was just a few percent of its current age.
      Initial observations of the survey region were re-photographed by Hubble after several years. This allowed the team to measure variations in the brightness of galaxies. These variations are a telltale sign of black holes. The team identified more black holes than previously found by other methods.
      The new observational results suggest that some black holes likely formed by the collapse of massive, pristine stars during the first billion years of cosmic time. These types of stars can only exist at very early times in the universe, because later-generation stars are polluted by the remnants of stars that have already lived and died. Other alternatives for black hole formation include collapsing gas clouds, mergers of stars in massive clusters, and “primordial” black holes that formed (by physically speculative mechanisms) in the first few seconds after the big bang. With this new information about black hole formation, more accurate models of galaxy formation can be constructed.
      “The formation mechanism of early black holes is an important part of the puzzle of galaxy evolution,” said Matthew Hayes from the Department of Astronomy at Stockholm University and lead author of the study. “Together with models for how black holes grow, galaxy evolution calculations can now be placed on a more physically motivated footing, with an accurate scheme for how black holes came into existence from collapsing massive stars.”
      Image Before/After Astronomers are also making observations with NASA’s James Webb Space Telescope to search for galactic black holes that formed soon after the big bang, to understand how massive they were and where they were located.
      The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
      Claire Andreoli
      NASA’s Goddard Space Flight Center, Greenbelt, MD
      claire.andreoli@nasa.gov
      Ray Villard
      Space Telescope Science Institute, Baltimore, MD
      Science Contact:
      Matthew Hayes
      Stockholm University, Stockholm, Sweden
      Share








      Details
      Last Updated Sep 17, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
      Astrophysics Astrophysics Division Black Holes Goddard Space Flight Center Hubble Space Telescope Missions The Universe Keep Exploring Discover More Topics From Hubble
      Hubble Space Telescope


      Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.


      Hubble Science Highlights



      Hubble Online Activities



      Hubble Focus: Dark Universe


      View the full article
    • By European Space Agency
      With the help of the NASA/ESA Hubble Space Telescope, an international team of researchers led by scientists in the Department of Astronomy at Stockholm University has found more black holes in the early Universe than has previously been reported. The new result can help scientists understand how supermassive black holes were created.
      View the full article
    • By NASA
      Hubble Space Telescope Home Hubble Examines a Spiral Star… Missions Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities   2 min read
      Hubble Examines a Spiral Star Factory
      This NASA/ESA Hubble Space Telescope image features the spiral galaxy NGC 5668. ESA/Hubble & NASA, C. Kilpatrick This NASA/ESA Hubble Space Telescope image features a spiral galaxy in the constellation Virgo named NGC 5668. It is relatively near to us at 90 million light-years from Earth and quite accessible for astronomers to study with both space- and ground-based telescopes. At first glance, it doesn’t seem like a remarkable galaxy. It is around 90,000 light-years across, similar in size and mass to our own Milky Way galaxy, and its nearly face-on orientation shows open spiral arms made of cloudy, irregular patches.
      One noticeable difference between the Milky Way galaxy and NGC 5668 is that this galaxy is forming new stars 60% more quickly. Astronomers have identified two main drivers of star formation in NGC 5668. Firstly, this high-quality Hubble view reveals a bar at the galaxy’s center, though it might look more like a slight oval shape than a real bar. The bar appears to have affected the galaxy’s star formation rate, as central bars do in many spiral galaxies. Secondly, astronomers tracked high-velocity clouds of hydrogen gas moving vertically between the disk of the galaxy and the spherical, faint halo which surrounds it. These movements may be the result of strong stellar winds from hot, massive stars, that would contribute gas to new star-forming regions.
      The enhanced star formation rate in NGC 5668 comes with a corresponding abundance of supernova explosions. Astronomers have spotted three in the galaxy, in 1952, 1954, and 2004. In this image, Hubble examined the surroundings of the Type II SN 2004G, seeking to study the kinds of stars that end their lives as this kind of supernova.

      Download this image

      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
      Claire Andreoli
      NASA’s Goddard Space Flight Center, Greenbelt, MD
      claire.andreoli@nasa.gov
      Share








      Details
      Last Updated Sep 12, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
      Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Hubble Space Telescope Missions Spiral Galaxies The Universe Keep Exploring Discover More Topics From Hubble
      Hubble Space Telescope


      Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.


      Hubble Focus: Galaxies through Space and Time


      Hubble Focus: Galaxies through Space and Time


      Hubble Science Highlights



      Name That Nebula


      View the full article
  • Check out these Videos

×
×
  • Create New...