Posts tagged Hubble Space Telescope
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Hubble Captures Colliding Galaxies
The Hubble Ultra Deep Field in 3D
Hubble Deep Field: The Most Important Image Ever Taken
This makes my heart hurt.
Cygnus X-1: Still a ‘Star’ (NASA, Chandra, 08/27/09)
Since its discovery 45 years ago, Cygnus X-1 has been one of the most intensively studied cosmic X-ray sources. About a decade after its discovery, Cygnus X-1 secured a place in the history of astronomy when a combination of X-ray and optical observations led to the conclusion that it was a black hole, the first such identification.
The Cygnus X-1 system consists of a black hole with a mass about 10 times that of the Sun in a close orbit with a blue supergiant star with a mass of about 20 Suns. Gas flowing away from the supergiant in a fast stellar wind is focused by the black hole, and some of this gas forms a disk that spirals into the black hole. The gravitational energy release by this infalling gas powers the X-ray emission from Cygnus X-1.
Although more than a thousand scientific articles have been published on Cygnus X-1, its status as a bright and nearby black hole continues to attract the interest of scientists seeking to understand the nature of black holes and how they affect their environment. Observations with Chandra and ESA’s XMM-Newton are especially valuable for studying the property of the stellar wind that fuels Cygnus X-1, and determining its rate of spin.
This latter research has revealed that Cygnus X-1 is spinning very slowly. This puzzling result could indicate that Cygnus X-1 may have formed in an unusual type of supernova that somehow prevented the newly formed black hole from acquiring as much spin as other stellar black holes.
Image credit: NASA/CXC
Read more about this image: chandra.harvard.edu/photo/2009/cygx1/
Crab Nebula: Energy for 100,000 Suns (NASA, Chandra, 11/23/09)
A star’s spectacular death in the constellation Taurus was observed on Earth as the supernova of 1054 A.D. Now, almost a thousand years later, a super dense object — called a neutron star — left behind by the explosion is seen spewing out a blizzard of high-energy particles into the expanding debris field known as the Crab Nebula. X-ray data from Chandra provide significant clues to the workings of this mighty cosmic “generator,” which is producing energy at the rate of 100,000 suns.
This composite image uses data from three of NASA’s Great Observatories. The Chandra X-ray image is shown in blue, the Hubble Space Telescope optical images are in yellow and red, and the Spitzer Space Telescope’s infrared image is in purple. The X-ray image is smaller than the others because extremely energetic electrons emitting X-rays radiate away their energy more quickly than the lower-energy electrons emitting optical and infrared light. Along with many other telescopes, Chandra has repeatedly observed the Crab Nebula over the course of the mission’s lifetime. The Crab Nebula is one of the most studied objects in the sky, truly making it a cosmic icon.
Read entire caption/view more images: chandra.harvard.edu/photo/2009/crab/
Image credit: X-ray: NASA/CXC/SAO/F.Seward; Optical: NASA/ESA/ASU/J.Hester & A.Loll; Infrared: NASA/JPL-Caltech/Univ. Minn./R.Gehrz
Caption credit: Harvard-Smithsonian Center for Astrophysics
Click here for a larger version of the image.
Lose yourself in a celestial lagoon
Alan Boyle writes
Most folks think of outer space as a vast emptiness, but if you look at the right place in the right light, you’ll find beautiful clouds of glory. The Lagoon Nebula in the constellation Sagittarius, also known as M8, is such a place. This region of the nebula, 5,000 light-years from Earth, is known as the “Southern Cliff” because of the sharp dropoff that can be seen in the clouds of glowing gas and dust.
The view captured by the Gemini South telescope in Chile does not reflect what the human eye would see. If you looked at the Lagoon through a good-sized amateur telescope, you’d see a pale ghostly glow with a touch of pink. But this picture was created using filters that are sensitive to emissions from hydrogen (red) and ionized sulfur (green), plus far-infrared light (shown here in blue). That explains the psychedelic color scheme.
As detailed in today’s image advisory from the Gemini Observatory, Argentinean astronomers Julia Arias and Rodolfo Barba of the Universidad de La Serena acquired the data for this image to explore the evolutionary relationship between newborn stars and the shock waves created by Herbig-Haro objects — that is, nebulous regions that are formed when the gas ejected from young stars collides with the clouds of gas and dust. About a dozen Herbig-Haro objects of varying size are visible here. But you don’t have to know the ins and outs of stellar formation to appreciate the vast abundance of the Lagoon.
Telescopes snag Meathook Galaxy
Two complementary views of the so-called Meathook Galaxy, released today, show how astronomers are piecing together the history of this lopsided group of stars.
The galaxy, located about 50 million light years away in the southern constellation Volans (The Flying Fish), is recognized for its asymmetrical spiral arms. One is tightly folded in on itself and host to a recent supernova, and the other is dotted with new star formation and extends far out from the nucleus.
The broa- view image above was taken by the Wide Field Imager the MPG/ESO 2.2-meter telescope at La Silla, Chile. It clearly shows the double hook shape that gives NGC 2442, as it the galaxy is officially known, its nickname.
The lopsided appearance is thought to be due to the gravitational interactions of another galaxy, though the culprit remains unknown, the European Space Agency noted in an image advisory. This interaction is probably responsible for an episode of recent star formation, seen as the patches of pink and red, particularly in the longer of the two spiral arms.
These colors come from hydrogen gas in star forming regions, ESA explains. As the powerful radiation of newborn stars excites the gas in the clouds they formed from, it glows in a bright shade of red.
The close-up view from the Hubble Space Telescope focuses on the nucleus of the Meathook and the more compact of its two spiral arms. Not seen in the image is a massive star that exploded at the end of its life in a supernova, witnessed in 1999. By comparing older ground-based observations, previous Hubble images and these made in 2006, astronomers have been able to study the details of the star’s violent death. By the time this image was made, the supernova had faded.
(Source: MSN)
Stellar Shrapnel Seen in Aftermath of Explosion (NASA, Chandra, 05/24/10)
This beautiful composite image shows N49, the aftermath of a supernova explosion in the Large Magellanic Cloud. A new long observation from NASA’s Chandra X-ray Observatory, shown in blue, reveals evidence for a bullet-shaped object being blown out of debris field left over from an exploded star.
In order to detect this bullet, a team of researchers led by Sangwook Park of Penn State University used Chandra to observe N49 for over 30 hours. This bullet can be seen in the bottom right hand corner of the image (see the labeled version of the image) and is rich in silicon, sulphur and neon. The detection of this bullet shows that the explosion that destroyed the star was highly asymmetric.
The bullet is traveling at a high speed of about 5 million miles an hour away from a bright point source in the upper left part of N49. This bright source may be a so-called soft gamma ray repeater (SGR), a source that emits bursts of gamma rays and X-rays. A leading explanation for these objects is that they are neutron stars with extremely powerful magnetic fields. Since neutron stars are often created in supernova explosions, an association between SGRs and supernova remnants is not unexpected. This case is strengthened by the apparent alignment between the bullet’s path and the bright X-ray source. However, the new Chandra data also shows that the bright source is more obscured by gas than expected if it really lies inside the supernova remnant. In other words, it is possible that the bright X-ray source actually lies beyond the remnant and is projected along the line of sight. Another possible bullet is located on the opposite side of the remnant, but it is harder to see in the image because it overlaps with the bright emission - described below - from the shock- cloud interaction.
Optical data from the Hubble Space Telescope (yellow and purple) shows bright filaments where the shock wave generated by the supernova is interacting with the densest regions in nearby clouds of cool, molecular gas.
Using the new Chandra data, the age of N49 — as it appears in the image — is thought to be about 5,000 years and the energy of the explosion is estimated to be about twice that of an average supernova. These preliminary results suggest that the original explosion was caused by the collapse of a massive star.
Read entire caption/view more images: chandra.harvard.edu/photo/2010/n49/
Image credit: X-ray: NASA/CXC/Penn State/S. Park et al. Optical: NASA/STScI/UIUC/Y.H. Chu & R. Williams et al.
Caption credit: Harvard-Smithsonian Center for Astrophysics
Supernova Explosions Stay in Shape (NASA, Chandra, 12/17/09)
These two supernova remnants are part of a new study from NASA’s Chandra X-ray Observatory that shows how the shape of the remnant is connected to the way the progenitor star exploded. In this study, a team of researchers examined the shapes of 17 supernova remnants in both the Milky Way galaxy and a neighbor galaxy, the Large Magellanic Cloud.
The results revealed that one category of supernova explosion, known as “Type Ia,” generated a very symmetric, circular remnant. This type of supernova is thought to be caused by a thermonuclear explosion of a white dwarf, and is often used by astronomers as a “standard candle” for measuring cosmic distances. The image in the right panel, the so- called Kepler supernova remnant, represents this type of supernova.
On the other hand, remnants tied to the “core collapse” family of supernova explosions were distinctly more asymmetric, which is seen in the morphology of the G292.0+1.8 remnant (left). The research team measured asymmetry in two ways: how spherical or elliptical the supernova remnant was and how much one side of the remnant mirrors its opposite side. In G292, the asymmetry is subtle but can be seen in elongated features defined by the brightest emission (colored white).
Out of the 17 supernova remnants sampled, ten were independently classified as the core-collapse variety, while the remaining seven of them were classified as Type Ia. One of these, a remnant known as SNR 0548-70.4, was a bit of an “oddball”. This one was considered a Type Ia based on its chemical abundances, but has the asymmetry of a core- collapse remnant.
Read entire caption/view more images: chandra.harvard.edu/photo/2009/typingsnrs/
Image credit: NASA/CXC/UCSC/L. Lopez et al.
Caption credit: Harvard-Smithsonian Center for Astrophysics
Andromeda Galaxy: Insights on White Dwarfs (NASA, Chandra, 02/17/10)
This composite image of M31 (also known as the Andromeda galaxy) shows X-ray data from NASA’s Chandra X-ray Observatory in gold, optical data from the Digitized Sky Survey in light blue and infrared data from the Spitzer Space Telescope in red. The Chandra data covers only the central region of M31 as shown in the inset box for the image.
New results show that the Chandra image would be about 40 times brighter than observed if Type Ia supernova in the bulge of this galaxy were triggered by material from a normal star falling onto a white dwarf star. This implies that the merger of two white dwarfs is the main trigger for Type Ia supernovas for the area observed by Chandra. Similar results for five elliptical galaxies were found. These findings represent a major advance in understanding the origin of Type Ia supernovas, explosions that are used as cosmic mile markers to measure the accelerated expansion of the universe and study dark energy. Most scientists agree that a Type Ia supernova occurs when a white dwarf star — a collapsed remnant of an elderly star — exceeds its weight limit, becomes unstable and explodes. However, there is uncertainty about what pushes the white dwarf over the edge, either accretion onto the white dwarf or a merger between two white dwarfs.
A Type Ia supernova caused by accreting material produces significant X-ray emission prior to the explosion. A supernova from a merger of two white dwarfs, on the other hand, would create significantly less. The scientists used the difference to decide between these two scenarios by examining the new Chandra data.
A third, less likely possibility is that the supernova explosion is triggered, in the accretion scenario, before the white dwarf reaches the expected mass limit. In this case, the detectable X-ray emission could be much lower than assumed for the accretion scenario. However, simulations of such explosions do not show agreement with the observed properties of Type Ia supernovas.
Read entire caption/view more images: chandra.harvard.edu/photo/2010/type1a/
Image credit: X-ray: NASA/CXC/MPA/M.Gilfanov & A.Bogdan; Infrared: NASA/JPL-Caltech/ SSC; Optical: DSS
Caption credit: Harvard-Smithsonian Center for Astrophysics
