Centaurus A, a prominent galaxy in the constellation of Centaurus, in a colour composite of images obtained with three instruments. Discovered in 1826 by James Dunlop, Centaurus A is a highly visible starburst galaxy which is only visible from low northern latitudes and the southern hemisphere.
Photograph: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)
One of our closest galactic neighbors shows its awesome beauty in this image from NASA’s Spitzer Space Telescope. M33, also known as the Triangulum Galaxy, is a member of what’s known as our Local Group of galaxies. Along with our own Milky Way, this group travels together in the universe, as they are gravitationally bound. In fact, M33 is one of the few galaxies that is moving toward the Milky Way despite the fact that space itself is expanding, causing most galaxies in the universe to grow farther and farther apart.
When viewed with Spitzer’s infrared eyes, this elegant spiral galaxy sparkles with color and detail. Stars appear as glistening blue gems (several of which are actually foreground stars in our own galaxy), while dust rich in organic molecules glows green. The diffuse orange-red glowing areas indicate star-forming regions, while small red flecks outside the spiral disk of M33 are most likely distant background galaxies. But not only is this new image beautiful, it also shows M33 to be surprising large – bigger than its visible-light appearance would suggest…
Arp 273 is a group of interacting galaxies, lying 300 million light years away in the constellation Andromeda and first discovered in 1966. In this photograph from the Hubble Space Telescope, the larger of the spiral galaxies, known as UGC 1810, has a disk that is tidally distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. A swath of blue jewels across the top is the combined light from clusters of intensely bright and hot young blue stars.
Galactic haloes may have 10 to 100 times as much matter as previously thought
by Stephen Ornes
Matter is the stuff in the universe. Astronomers say most of the matter in any galaxy — and in the universe — is dark matter, which is mysterious and invisible and difficult to study. The new research focuses on ordinary matter, which is visible and known to consist of particles. Ordinary matter makes up the stuff scientists can see and measure. Mass is a measure of how much matter something has.
Galaxies are enormous collections of stars. Typically, a galaxy has millions or billions of them. Each star, in turn, may hold planets in tow. A galaxy also may host very dense black holes. Together, all of these celestial bodies contain a lot of mass. But not enough: Galaxies should have about three times as much ordinary matter as astronomers see.
That’s where haloes come in. These are giant spheres of gas and dark matter that surround galaxies. And glow. That shouldn’t be too surprising: Much of a halo’s gas has a scorching temperature of a million degrees Celsius (1.8 million degrees Fahrenheit) or more. But haloes also contain much cooler gas that’s only about 10,000 ºC (or about 18,000 ºF). That cooler gas barely emits any light. Which means ordinary telescopes can’t see it…
Astronomers have for the first time captured a glimpse of the vast, web-like network of diffuse gas that links all of the galaxies in the cosmos.
Leading cosmological theories suggest that galaxies are cocooned within gigantic, wispy filaments of gas. This “cosmic web” of gas-filled nebulas stretches between large, spacious voids that are tens of millions of light years wide. Like spiders, galaxies mostly appear to lie within the intersections of the long-sought webs.
In observations spied through one of the most powerful telescopes in the world, the 33-foot (10-meter) Keck I Telescope in Hawaii, astronomers led by Sebastiano Cantalupo of the University of California, Santa Cruz, now report that they have detected a very large, luminous filament of gas extending about 2 million light-years across intergalactic space, exactly as predicted by theory.
Essentially, the filament reported in the January 19 Nature represents one of the strands of the cosmic web that holds together the galaxy-rich universe. Astronomers hope to understand both the structure of the universe and the development of galaxies such as our own Milky Way by unraveling the secrets of the cosmic web…
This week, the light from a star that exploded 12 million years ago finally reached earth.
Astronomers observed the supernova in galaxy M82. Shown here are two views of that galaxy: the first photo taken in December, and the second yesterday, showing the new giant ball of light. Despite being 12 million light-years away, M82 is considered to be practically a next-door neighbor of our own galaxy, and is easily viewable by backyard astronomers.
Supernovas are caused by either the sudden gravitational collapse of the core of a massive star, or the accumulation of material in a dwarf star that raises the core temperature and triggers runaway nuclear fusion. They are short-lived, but not instant events - the light from the explosion can last for weeks or even months before fading out. This particular star was a white dwarf, and its supernova is expected to continue to brighten for the next two weeks as the explosion grows. The energy released in a single supernova event can often exceed what our Sun will emit over its entire lifespan.
Across the thousands of galaxies in the entire universe supernovae are quite common - astronomers record a few hundred new ones every year. While none have been observed within the Milky Way since 1604, observed supernova remnants suggest our galaxy sees two to three per century. This is the nearest supernova to Earth in 21 years.
Photo: UCL Mathematical and Physical Sciences on Flickr
Hubble’s first frontier field finds thousands of unseen, faraway galaxies
(Phys.org) —The first of a set of unprecedented, super-deep views of the universe from an ambitious collaborative program called The Frontier Fields is being released today at the 223rd meeting of the American Astronomical Society in Washington, D.C.
The long-exposure image taken with NASA’s Hubble Space Telescope is the deepest-ever picture taken of a cluster of galaxies, and also contains images of some of the intrinsically faintest and youngest galaxies ever detected.
The target is the massive cluster Abell 2744, which contains several hundred galaxies as they looked 3.5 billion years ago. The immense gravity in this foreground cluster is being used as a “gravitational lens,” which warps space to brighten and magnify images of far more-distant background galaxies as they looked over 12 billion years ago, not long after the big bang… (read more)
The Milky Way has twice the number of spiral arms than recent observations suggested. That’s according to a new analysis—part of the biggest census of star-forming regions to date—that focused on stars eight times the mass of our sun or larger (the size that eventually explode as supernovae) at a very early stage in their lifetime, when they’d still be inside the clouds of gas and dust where they formed.
The researchers identified about 1650 such stars and then estimated the distance to those stars (red dots in image; the black dot denotes the position of our solar system). For the most part, the stars lie along four spiral arms (artist’s representation of the Milky Way, background image), the researchers report online today in the Monthly Notices of the Royal Astronomical Society…
Fast, Furious, Refined: Smaller Black Holes Can Eat Plenty
- Gemini Observatory Press Release
Gemini observations support an unexpected discovery in the galaxy Messier 101. A relatively small black hole (20-30 times the mass of our Sun), ULX-1, can sustain a hugely voracious appetite while consuming material in an efficient and tidy manner – something previously thought impossible. The research also affects the long quest for elusive intermediate-mass black holes. The findings are published in the November 28, 2013, issue of the journal Nature…
(PhysOrg) - Astronomers using the combined power of the Atacama Large Millimeter/submillimeter Array (ALMA) telescope and NASA’s Hubble Space Telescope have discovered a far-flung trio of primitive galaxies nestled inside an enormous blob of primordial gas nearly 13 billion light-years from Earth.
"This exceedingly rare triple system, seen when the Universe was only 800 million years old, provides important insights into the earliest stages of galaxy formation during a period known as ‘Cosmic Dawn,’ when the Universe was first bathed in starlight," said Richard Ellis, the Steele Professor of Astronomy at the California Institute of Technology and member of the research team. "Even more interesting, these galaxies appear poised to merge into a single massive galaxy, which could eventually evolve into something akin to the Milky Way."…
(Image: NASA/Hubble. The image in the upper right is a close-up of Himiko with Hubble. The three infant galaxies are clearly resolved where only one was known to exist before. These objects are extremely energetic, suggesting they are undergoing a period of intense star formation.
CREDIT: NASA/Hubble. The image in the lower right is the same object with additional data from the Spitzer Space Telescope and Subaru Telescope on Mauna Kea in Hawaii. The halo of ionized hydrogen gas is clearly seen surrounding Himiko. Observations with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope did not detect any telltale signature from carbon, suggesting that these three objects may be very primitive and have not had enough time to seed the intergalactic medium with heavy elements. Credit: NASA/Hubble; NASA/Spitzer; NAOJ/Subaru)
Chandra helps confirm evidence of jet in Milky Way’s black hole
(Phys.org) — Astronomers have long sought strong evidence that Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, is producing a jet of high-energy particles. Finally they have found it, in new results from NASA’s Chandra X-ray Observatory and the National Science Foundation’s Very Large Array (VLA) radio telescope.
Jets of high-energy particles are found throughout the universe, on large and small scales. They are produced by young stars and by black holes a thousand times larger than the Milky Way’s black hole. They play important roles in transporting energy away from the central object and, on a galactic scale, in regulating the rate of formation of new stars…
Nature Pulls a Fast One - 2 Galaxies Masquerade As 1
by Whitney Clavin
What might look like a colossal jet shooting away from a galaxy turns out to be an illusion. New data from the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) reveal that two galaxies, one lying behind the other, have been masquerading as one.
In a new image highlighting the chance alignment, radio data from the VLA are blue and infrared observations from NASA’s Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) are yellow and orange, respectively. Visible data are also shown, with starlight in purplish blue and heated gas in rose.
The closer galaxy, called UGC 10288, is located 100 million light-years away. It is spiral in shape, but from our viewpoint on Earth, we are seeing its thin edge. The farther galaxy, seen in blue, is nearly 7 billion light-years away. Two giant jets shoot away from this galaxy, one of which is seen above the plane of the closer galaxy’s disk…
This cluster of stars is known as Messier 15, and is located some 35 000 light-years away in the constellation of Pegasus (The Winged Horse). It is one of the oldest globular clusters known, with an age of around 12 billion years.
Both very hot blue stars and cooler golden stars can be seen swarming together in the image, becoming more concentrated towards the cluster’s bright centre. Messier 15 is one of the densest globular clusters known, with most of its mass concentrated at its core. As well as stars, Messier 15 was the first cluster known to host a planetary nebula, and it has been found to have a rare type of black hole at its centre.
This new image is made up of observations from Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys in the ultraviolet, infrared, and optical parts of the spectrum.
Galactic Cirrus clouds billow and obscure the background Universe in this direction. NGC 7497 is seen through partly cloudy skies. These galactic clouds of dust are sculpted by the winds of nearby stars. They are relatively close to us (only hundreds of light years away) and there are few stars in the foreground to hinder of view of them. The color of the clouds is odd due to the fact they are illuminated mostly by diffuse galactic star light.
Image: Adam Block/Mount Lemmon SkyCenter/University of Arizona [high-resolution]
NGC 6946 is a medium-sized, face-on spiral galaxy about 22 million light years away from Earth. In the past century, eight supernovas have been observed to explode in the arms of this galaxy. Chandra observations (purple) have, in fact, revealed three of the oldest supernovas ever detected in X-rays, giving more credence to its nickname of the “Fireworks Galaxy.” This composite image also includes optical data from the Gemini Observatory in red, yellow, and cyan.
Image: X-ray: NASA/CXC/MSSL/R.Soria et al, Optical: AURA/Gemini OBs [high-resolution]