Earth designation NGC 2392 Eskimo Nebula from the ground might resemble a person's head surrounded by a parka hood Hubble Space Telescope imaged Eskimo Nebula in visible light in 2000 The nebula was imaged in X-rays by the Chandra X-ray Observatory in 2007
|Image from Spitzer Space Telescope. Spitzer image transforms a dark cloud into a silky translucent veil, revealing the stellar winds from an otherwise hidden newborn star called HH46-IR. Spitzer's remarkable capacity to peer through cosmic dust has allowed it to unveil this never-before-seen star. Best viewed in full screen.|
This Hubble Space Telescope image provides a detailed look at a brilliant 'fireworks show' at the center of a collision between two galaxies. Hubble has uncovered over 1,000 bright, young star clusters bursting to life as a result of the head-on wreck. The respective cores of the twin galaxies are the orange blobs, left and right of image center, crisscrossed by filaments of dark dust. A wide band of chaotic dust, called the overlap region, stretches between the cores of the two galaxies. The sweeping spiral-like patterns, traced by bright blue star clusters, shows the result of a firestorm of star birth activity which was triggered by the collision. This natural-color image is a composite of four separately filtered images taken with the Wide Field Planetary Camera 2 (WFPC2), on January 20, 1996. [Below] A ground-based telescopic view of the Antennae galaxies (known formally as NGC 4038/4039) so named because a pair of long tails of luminous matter, formed by the gravitational tidal forces of their encounter, resembles an insect's antennae. The galaxies are located 63 million light-years away in the southern constellation Corvus.
Picture: Brad Whitmore (STScI), and NASA
A ground-based telescopic view of the Antennae galaxies (known formally as NGC 4038/4039) so named because a pair of long tails of luminous matter, formed by the gravitational tidal forces of their encounter, resembles an insect's antennae. The galaxies are located 63 million light-years away in the southern constellation Corvus. [Right] This Hubble Space Telescope image provides a detailed look at a brilliant 'fireworks show' at the center of a collision between two galaxies. Hubble has uncovered over 1,000 bright, young star clusters bursting to life as a result of the head-on wreck. The respective cores of the twin galaxies are the orange blobs, left and right of image center, crisscrossed by filaments of dark dust. A wide band of chaotic dust, called the overlap region, stretches between the cores of the two galaxies. The sweeping spiral-like patterns, traced by bright blue star clusters, shows the result of a firestorm of star birth activity which was triggered by the collision. This natural-color image is a composite of four separately filtered images taken with the Wide Field Planetary Camera 2 (WFPC2), on January 20, 1996.
Picture: Brad Whitmore (STScI), and NASA
Image of the rich galaxy cluster, Abell 2218. This NASA Hubble Space Telescope image is a spectacular example of gravitational lensing. The arc-like pattern spread across the picture like a spider web is an illusion caused by the gravitational field of the cluster. The cluster is so massive and compact that light rays passing through it are deflected by its enormous gravitational field, much as an optical lens bends light to form an image. The process magnifies, brightens and distorts images of objects that lie far beyond the cluster. This provides a powerful "zoom lens" for viewing galaxies that are so far away they could not normally be observed with the largest available telescopes. A rare multiple imaging happens when distortion is large enough to produce more than one image of the same galaxy. Abell 2218 has an unprecedented total of seven multiple systems. The abundance of lensing features in Abell 2218 has been used to make a detailed map of the distribution of matter in the cluster's center. From this, distances can be calculated for a sample of 120 faint arclets found on the Hubble image. These arclets represent galaxies that are 50 times fainter than objects that can be seen with ground-based telescopes. Studies of remote galaxies promise to reveal the nature of normal galaxies at much earlier epochs than was previously possible.
Picture: W.Couch (University of New South Wales), R. Ellis (Cambridge University), and NASA
Light And Shadow In The Carina Nebula Previously unseen details of a mysterious, complex structure within the Carina Nebula (NGC 3372) are revealed by this image of the 'Keyhole Nebula.' Obtained with NASA's Hubble Space Telescope, the picture is a montage assembled from four different April 1999 telescope pointings with Hubble's Wide Field Planetary Camera 2, which used six different color filters. The picture is dominated by a large, approximately circular feature, which is part of the Keyhole Nebula, named in the 19th century by Sir John Herschel. This region, about 8000 light-years from Earth, is located adjacent to the famous explosive variable star Eta Carinae, which lies just outside the field of view toward the upper right. The Carina Nebula also contains several other stars that are among the hottest and most massive known, each about 10 times as hot, and 100 times as massive, as our Sun. The circular Keyhole structure contains both bright filaments of hot, fluorescing gas, and dark silhouetted clouds of cold molecules and dust, all of which are in rapid, chaotic motion. The high resolution of the Hubble images reveals the relative three-dimensional locations of many of these features, as well as showing numerous small dark globules that may be in the process of collapsing to form new stars. Two striking large, sharp-edged dust clouds are located near the bottom center and upper left edges of the image. The former is immersed within the ring and the latter is just outside the ring. The pronounced pillars and knobs of the upper left cloud appear to point toward a luminous, massive star located just outside the field further toward the upper left, which may be responsible for illuminating and sculpting them by means of its high-energy radiation and stellar wind of high-velocity ejected material. These large dark clouds may eventually evaporate, or if there are sufficiently dense condensations within them, give birth to small star clusters. The Carina Nebula, with an overall diameter of more than 200 light-years, is one of the outstanding features of the Southern-Hemisphere portion of the Milky Way. The diameter of the Keyhole ring structure shown here is about 7 light-years. These data were collected by the Hubble Heritage Team and Nolan R. Walborn (STScI), Rodolfo H. Barba' (La Plata Observatory, Argentina), and Adeline Caulet (France).
Image Credit: NASA, The Hubble Heritage Team (AURA/STScI)
A ground-based image of the entire Crab Nebula. The remnant of a supernova explosion witnessed over 900 years ago. The nebula, which is 10 light-years across, is located 7,000 light-years away in the constellation Taurus. The green, yellow and red filaments concentrated toward the edges of the nebula are remnants of the star that were ejected into space by the explosion. At the center of the Crab Nebula lies the Crab Pulsar the collapsed core of the exploded star. The Crab Pulsar is a rapidly rotating neutron star an object only about six miles across, but containing more mass than our Sun. As it rotates at a rate of 30 times per second the Crab Pulsar's powerful magnetic field sweeps around, accelerating particles, and whipping them out into the nebula at speeds close to that of light. The blue glow in the inner part of the nebula light emitted by energetic electrons as they spiral through the Crab's magnetic field is powered by the Crab Pulsar. Below is an image of the inner parts of the Crab.
The picture is a Hubble Space Telescope image of the inner parts of the Crab. The pulsar itself is visible as the left of the pair of stars near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features. This image is one of a sequence of Hubble images taken over the course of several months. This sequence shows that the inner part of the Crab Nebula is far more dynamic than previously understood. The Crab literally "changes it stripes" every few days as these wisps stream away from the pulsar at half the speed of light. The Hubble Space Telescope photo was taken Nov. 5, 1995 by the Wide Field and Planetary Camera 2 at a wavelength of around 550 nanometers, in the middle of the visible part of the electromagnetic spectrum.
Picture: Jeff Hester and Paul Scowen (Arizona State University), and NASA
MyCn18, a young planetary nebula located about 8,000 light-years away. This Hubble image reveals the true shape of MyCn18 to be an hourglass with an intricate pattern of 'etchings' in its walls. This picture has been composed from three separate images taken in the light of ionized nitrogen (represented by red), hydrogen (green), and doubly-ionized oxygen (blue). The results are of great interest because they shed new light on the poorly understood ejection of stellar matter which accompanies the slow death of Sun-like stars. In previous ground-based images, MyCn18 appears to be a pair of large outer rings with a smaller central one, but the fine details cannot be seen. According to one theory for the formation of planetary nebulae, the hourglass shape is produced by the expansion of a fast stellar wind within a slowly expanding cloud which is more dense near its equator than near its poles. What appears as a bright elliptical ring in the center, and at first sight might be mistaken for an equatorially dense region, is seen on closer inspection to be a potato shaped structure with a symmetry axis dramatically different from that of the larger hourglass. The hot star which has been thought to eject and illuminate the nebula, and therefore expected to lie at its center of symmetry, is clearly off center. Hence MyCn18, as revealed by Hubble, does not fulfill some crucial theoretical expectations. Hubble has also revealed other features in MyCn18 which are completely new and unexpected. For example, there is a pair of intersecting elliptical rings in the central region which appear to be the rims of a smaller hourglass. There are the intricate patterns of the etchings on the hourglass walls. The arc-like etchings could be the remnants of discrete shells ejected from the star when it was younger (e.g. as seen in the Egg Nebula), flow instabilities, or could result from the action of a narrow beam of matter impinging on the hourglass walls. An unseen companion star and accompanying gravitational effects may well be necessary in order to explain the structure of MyCn18. Background: Planetary Nebulae When Sun-like stars get old, they become cooler and redder, increasing their sizes and energy output tremendously: they are called red giants. Most of the carbon (the basis of life) and particulate matter (crucial building blocks of solar systems like ours) in the universe is manufactured and dispersed by red giant stars. When the red giant star has ejected all of its outer layers, the ultraviolet radiation from the exposed hot stellar core makes the surrounding cloud of matter created during the red giant phase glow: the object becomes a planetary nebula. A long-standing puzzle is how planetary nebulae acquire their complex shapes and symmetries, since red giants and the gas/dust clouds surrounding them are mostly round. Hubble's ability to see very fine structural details (usually blurred beyond recognition in ground-based images) enables us to look for clues to this puzzle.
Picture: Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA
Cometary knots around a dying star. Closer view of the "cometary knots" in the Helix Nebula. These gigantic, tadpole-shaped objects are probably the result of a dying star's last gasps. Dubbed 'cometary knots' because their glowing heads and gossamer tails resemble comets, the gaseous objects probably were formed during a star's final stages of life. Hubble astronomer C. Robert O'Dell and graduate student Kerry P. Handron of Rice University in Houston, Texas discovered thousands of these knots with the Hubble Space Telescope while exploring the Helix nebula, the closest planetary nebula to Earth at 450 light-years away in the constellation Aquarius. Although ground-based telescopes have revealed such objects, astronomers have never seen so many of them. The most visible knots all lie along the inner edge of the doomed star's ring, trillions of miles away from the star's nucleus. Although these gaseous knots appear small, they're actually huge. Each gaseous head is at least twice the size of our solar system; each tail stretches for 100 billion miles, about 1,000 times the distance between the Earth and the Sun. Astronomers theorize that the doomed star spews hot, lower-density gas from its surface, which collides with cooler, higher-density gas that had been ejected 10,000 years before. The crash fragments the smooth cloud surrounding the star into smaller, denser finger-like droplets, like dripping paint. This image was taken in August, 1994 with Hubble's Wide Field Planetary Camera 2. The red light depicts nitrogen emission ([NII] 6584A); green, hydrogen (H-alpha, 6563A); and blue, oxygen (5007A).
Picture: Robert O'Dell, Kerry P. Handron (Rice University, Houston, Texas) and NASA
'Twisters' in the Lagoon Nebula. This image reveals a pair of one-half light-year long interstellar giant twisters eerie funnels and twisted-rope structures in the heart of the Lagoon Nebula (Messier 8) which lies 5,000 light-years away in the direction of the constellation Sagittarius. The central hot star, O Herschel 36 (lower right), is the primary source of the ionizing radiation for the brightest region in the nebula, called the Hourglass. Other hot stars, also present in the nebula, are ionizing the extended optical nebulosity. The ionizing radiation induces photo-evaporation of the surfaces of the clouds and drives away violent stellar winds tearing into the cool clouds. The large difference in temperature between the hot surface and cold interior of the clouds, combined with the pressure of starlight, may produce strong horizontal shear to twist the clouds into their tornado-like appearance. Though the spiral shapes suggest the clouds are 'twisting', future observations will be needed, perhaps with Hubble's next generation instruments, with the spectroscopic capabilities of the Space Telescope Imaging Spectrograph (STIS) or the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), to actually measure velocities. The Lagoon Nebula and nebulae in other galaxies are sites where new stars are being born from dusty molecular clouds. These regions act as space laboratories for the astronomers to study how stars form and the interactions between the winds from stars and the gas nearby. By studying the wealth of data revealed by HST, astronomers will understand better how stars form in the nebulae. These color-coded images are the combination of individual exposures taken in July and September, 1995 with NASA Hubble Space Telescope (HST), Hubble's Wide Field and Planetary Camera 2 (WFPC2) through three narrow-band filters (red light ionized sulphur atoms, blue light double ionized oxygen atoms, green light ionized hydrogen). This work is based on public data retrieved from the HST Archive, cosmic-ray cleaned, calibrated and combined by Adeline Caulet (Space Telescope European Coordinating Facility, European Space Agency).
Picture: A. Caulet (ST-ECF, ESA) and NASA
Coincidentally aligned spiral galaxies. (NGC 3314). This image shows the unique "Galactic Silhouettes," the galaxy pair called NGC 3314. Through an extraordinary chance alignment, a face-on spiral galaxy lies precisely in front of another larger spiral. This line-up provides us with the rare chance to visualize dark material within the front galaxy, seen only because it is silhouetted against the object behind it. Dust lying in the spiral arms of the foreground galaxy stands out where it absorbs light from the more distant galaxy. This silhouetting shows us where the interstellar dust clouds are located, and how much light they absorb. The outer spiral arms of the front galaxy appear to change from bright to dark, as they are projected first against deep space, and then against the bright background of the other galaxy. NGC 3314 lies about 140 million light-years from Earth, in the direction of the southern hemisphere constellation Hydra. The bright blue stars forming a pinwheel shape near the center of the front galaxy have formed recently from interstellar gas and dust. In many galaxies, interstellar dust lies only in the same regions as recently formed blue stars. However, in the foreground galaxy, NGC 3314a, there are numerous additional dark dust lanes that are not associated with any bright young stars. A small, red patch near the center of the image is the bright nucleus of the background galaxy, NGC 3314b. It is reddened for the same reason the setting sun looks red. When light passes through a volume containing small particles (molecules in the Earth's atmosphere or interstellar dust particles in galaxies), its color becomes redder. The image is from NASA's Hubble Space Telescope and its Wide Field Planetary Camera 2 (WFPC2). The Hubble Heritage color image of NGC 3314 was constructed from archival images taken with WFPC2 in April 1999 by Drs. William Keel and Ray White III (University of Alabama) in blue and infrared light, combined with new images obtained by the Heritage team in March 2000 using blue, green and red filters.
Picture: NASA and The Hubble Heritage Team (STScI/AURA)
The dusty, star-studded arms of M81, a nearby spiral galaxy similar to our own, are illuminated in unprecedented detail in this Spitzer Space Telescope image. M81 is among the nearest and brightest spiral galaxies. The glowing, stellar nursery is visible even with binoculars at dark sites. M81 was discovered by Johann Elert Bode who first identified it in 1774. A dust lane runs through the disk, below and right of the galactic center, possibly the result of a close encounter between M81 and a smaller companion galaxy, M82. The spiral galaxy M81 is the brightest and probably is the dominant galaxy of a group called the M81 group. The bright yellow hue at the nucleus of the M81 group indicates an ancient population of stars many billions of years old.
Spiral galaxy NGC 3627 is located about 30 million light years from Earth. This composite image includes X-ray data from NASA's Chandra X-ray Observatory (blue), infrared data from the Spitzer Space Telescope (red), and optical data from the Hubble Space Telescope and the Very Large Telescope (yellow). The inset shows the central region, which contains a bright X-ray source that is likely powered by material falling onto a supermassive black hole. A search using archival data from previous Chandra observations of a sample of 62 nearby galaxies has shown that 37 of the galaxies, including NGC 3627, contain X-ray sources in their centers. Most of these sources are likely powered by central supermassive black holes. The survey, which also used data from the Spitzer Infrared Nearby Galaxy Survey, found that seven of the 37 sources are new supermassive black hole candidates. Confirming previous Chandra results, this study finds the fraction of galaxies found to be hosting supermassive black holes is much higher than found with optical searches. This shows the ability of X-ray observations to find black holes in galaxies where relatively low-level black hole activity has either been hidden by obscuring material or washed out by the bright optical light of the galaxy. The combined X-ray and infrared data suggest that the nuclear activity in a galaxy is not necessarily related to the amount of star-formation in the galaxy, contrary to some early claims. In contrast, these new results suggest that the mass of the supermassive black hole and the rate at which the black hole accretes matter are both greater for galaxies with greater total masses. A paper describing these results was published in the April 10, 2011 issue of The Astrophysical Journal. The authors are Catherine Grier and Smita Mathur of The Ohio State University in Columbus, OH; Himel GHosh of CNRS/CEA-Saclay in Guf-sur-Yvette, France and Laura Ferrarese from Herzberg Institute of Astrophysics in Victoria, Canada. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.
Picture: NASA and Spitzer Caltech
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