Hubble's True Blue Compact Dwarf
This NASA/ESA Hubble Space Telescope image shows a galaxy known as UGC 11411. It is a galaxy type known as an irregular blue compact dwarf (BCD) galaxy.
BCD galaxies are about a tenth of the size of a typical spiral galaxy
such as the Milky Way and are made up of large clusters of hot, massive
stars that ionize the surrounding gas with their intense radiation.
Because these stars are so hot they glow brightly with a blue hue,
giving galaxies like UGC 11411 their characteristic blue tint. With
these massive stars being less than 10 million years old, they are very
young compared to stellar standards. They were created during a
starburst, a galaxy-wide episode of furious star formation. UGC 11411 in
particular has an extremely high star formation rate, even for a BCD
galaxy.
Unusually for galaxies with such intense star-forming regions, BCDs
don’t contain either a lot of dust, or the heavy elements that are
typically found as trace elements in recently formed stars, making their
composition very similar to that of the material from which the first
stars formed in the early universe. Because of this astronomers consider
BCD galaxies to be good objects to study to improve our understanding
of primordial star-forming processes.
The bright stars in the image are foreground stars in our own Milky Way galaxy.
Image credit: ESA/Hubble & NASA
Text credit: European Space Agency
Text credit: European Space Agency
Last Updated: June 21, 2015
Editor: Ashley Morrow
Tags: Galaxies, Goddard Space Flight Center, Hubble Space Telescope, Universe
Hubble Meeting the Neighbors
There are many galaxies in the universe and although there is plenty of room, they tend to stick together. The Milky Way, for example, is part of a large gathering of more than fifty galaxies known as the Local Group. Galaxy groups like this come together to form even larger groups called clusters which can congregate further still to create mammoth superclusters.
The sphere of space surrounding our galaxy is known as the Local
Volume, a region some 35 million light-years in diameter and home to
several hundred known galaxies. The subject of this new NASA/ESA Hubble
Space Telescope image, a beautiful dwarf irregular galaxy known as PGC
18431, is one of these galaxies.
This image shows PGC 18431 smudged across the sky, but it wasn’t imaged purely for its looks. These Hubble observations were gathered in order to probe how Local Volume galaxies cluster together and move around. Hubble’s high resolution allows astronomers to explore star populations within these moderately distant galaxies — specifically, stars known as tip of the red giant branch stars — in order to get an idea of the galaxy’s composition and, crucially, its distance from us. Knowing galactic distances enables us to accurately map a galaxy sample in three dimensions, a method key to understanding more about our cosmic neighbors, and to dismiss perspective and line-of-sight illusions.
Image credit: ESA/Hubble & NASA
Text credit: European Space Agency
This image shows PGC 18431 smudged across the sky, but it wasn’t imaged purely for its looks. These Hubble observations were gathered in order to probe how Local Volume galaxies cluster together and move around. Hubble’s high resolution allows astronomers to explore star populations within these moderately distant galaxies — specifically, stars known as tip of the red giant branch stars — in order to get an idea of the galaxy’s composition and, crucially, its distance from us. Knowing galactic distances enables us to accurately map a galaxy sample in three dimensions, a method key to understanding more about our cosmic neighbors, and to dismiss perspective and line-of-sight illusions.
Image credit: ESA/Hubble & NASA
Text credit: European Space Agency
Last Updated: June 21, 2015
Editor: Ashley Morrow
Tags: Galaxies, Goddard Space Flight Center, Hubble Space Telescope, Image of the Day, Universe
Lonely Galaxy Lost in Space
Most galaxies are clumped together in groups or clusters. A neighboring galaxy is never far away. But this galaxy, known as NGC 6503, has found itself in a lonely position, at the edge of a strangely empty patch of space called the Local Void.
The Local Void is a huge stretch of space that is at least 150
million light-years across. It seems completely empty of stars or
galaxies. The galaxy’s odd location on the edge of this never-land led
stargazer Stephen James O’Meara to dub it the “Lost-In-Space galaxy” in
his 2007 book, Hidden Treasures.
NGC 6503 is 18 million light-years away from us in the northern circumpolar constellation of Draco. NGC 6503 spans some 30,000 light-years, about a third of the size of the Milky Way.
This Hubble Space Telescope image shows NGC 6503 in striking detail and with a rich set of colors. Bright red patches of gas can be seen scattered through its swirling spiral arms, mixed with bright blue regions that contain newly forming stars. Dark brown dust lanes snake across the galaxy’s bright arms and center, giving it a mottled appearance.
The Hubble Advanced Camera for Surveys data for NGC 6503 were taken in April 2003, and the Wide Field Camera 3 data were taken in August 2013.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
Photo Credit: NASA, ESA, D. Calzetti (University of Massachusetts), H. Ford (Johns Hopkins University), and the Hubble Heritage Team
For images and more information about the Hubble Space Telescope, visit: http://www.nasa.gov/hubble or http://hubblesite.org/news/2015/23
NGC 6503 is 18 million light-years away from us in the northern circumpolar constellation of Draco. NGC 6503 spans some 30,000 light-years, about a third of the size of the Milky Way.
This Hubble Space Telescope image shows NGC 6503 in striking detail and with a rich set of colors. Bright red patches of gas can be seen scattered through its swirling spiral arms, mixed with bright blue regions that contain newly forming stars. Dark brown dust lanes snake across the galaxy’s bright arms and center, giving it a mottled appearance.
The Hubble Advanced Camera for Surveys data for NGC 6503 were taken in April 2003, and the Wide Field Camera 3 data were taken in August 2013.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
Photo Credit: NASA, ESA, D. Calzetti (University of Massachusetts), H. Ford (Johns Hopkins University), and the Hubble Heritage Team
For images and more information about the Hubble Space Telescope, visit: http://www.nasa.gov/hubble or http://hubblesite.org/news/2015/23
Last Updated: June 21, 2015
Editor: Lynn Jenner
Tags: Galaxies, Goddard Space Flight Center, Hubble Space Telescope, Image of the Day, Universe
Hubble Sees a Fascinating Core
This elliptical galaxy was discovered in March 1781 and lies
about 60 million light-years away from Earth in the constellation of
Virgo (The Virgin). The galaxy is part of the very heavily populated
center of the Virgo Cluster, a cluster which consists of more than 1,000
galaxies.
This image does not show the whole galaxy but only its very
interesting center with intriguing dust lanes that stretch across it.
This is likely to be the best image of the region ever captured.
Previous observations using Hubble’s Space Telescope Imaging
Spectrograph (STIS) revealed a supermassive black hole in the center of
Messier 84. Astronomers found the supermassive black hole by mapping the
motion of the gas and the stars which are caught in its grip.
Next to its interesting center Messier 84 is also known for its
supernovae. Two supernovae have been observed within the galaxy. The
first, SN1957, was discovered in 1957 and another, called SN1991bg, was
discovered in 1991.
Image credit: ESA/Hubble & NASA
Text credit: European Space Agency
Text credit: European Space Agency
Last Updated: June 21, 2015
Editor: Ashley Morrow
Tags: Galaxies, Goddard Space Flight Center, Hubble Space Telescope, Universe
Hubble Peers into the Most Crowded Place in the Milky Way
This NASA/ESA Hubble Space Telescope image presents the Arches Cluster, the densest known star cluster in the Milky Way. It is located about 25,000 light-years from Earth in the constellation of Sagittarius (The Archer), close to the heart of our galaxy, the Milky Way. It is, like its neighbor the Quintuplet Cluster, a fairly young astronomical object at between two and four million years old.
The Arches cluster is so dense that in a region with a radius equal
to the distance between the sun and its nearest star there would be over
100,000 stars! At least 150 stars within the cluster are among the
brightest ever discovered in the Milky Way. These stars are so bright
and massive that they will burn their fuel within a short time (on a
cosmological scale that means just a few million years). Then they will
die in spectacular supernova explosions. Due to the short lifetime of
the stars in the cluster the gas between the stars contains an unusually
high amount of heavier elements, which were produced by earlier
generations of stars.
Despite its brightness the Arches Cluster cannot be seen with the naked eye. The visible light from the cluster is completely obscured by gigantic clouds of dust in this region. To make the cluster visible astronomers have to use detectors which can collect light from the X-ray, infrared, and radio bands, as these wavelengths can pass through the dust clouds. This observation shows the Arches Cluster in the infrared and demonstrates the leap in Hubble’s performance since its 1999 image of same object.
Image credit: NASA/ESA
Text credit: European Space Agency
Despite its brightness the Arches Cluster cannot be seen with the naked eye. The visible light from the cluster is completely obscured by gigantic clouds of dust in this region. To make the cluster visible astronomers have to use detectors which can collect light from the X-ray, infrared, and radio bands, as these wavelengths can pass through the dust clouds. This observation shows the Arches Cluster in the infrared and demonstrates the leap in Hubble’s performance since its 1999 image of same object.
Image credit: NASA/ESA
Text credit: European Space Agency
Last Updated: June 21, 2015
Editor: Ashley Morrow
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