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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Radio Galaxies Unit Type:Legacy Astronomical Image |
Description:VLBA 2 cm image of the radio galaxy 0402+379, which hosts two active supermassive black holes at its center. The location of each supermassive black hole is indicated on the image by an artist's conception of an accretion disk with narrow twin jets. These results are based upon multi-epoch, multi-frequency monitoring with the VLBA. The projected separation between the two black holes is 7.3 parsecs, making this the most compact binary black hole pair yet found by more than two orders of magnitude. The combined mass of the system is estimated at ~1.5 x 10^8 solar masses, and assuming equal masses the orbital period is 150,000 years. Though gravitational radiation from this system is not yet enough to cause the orbit to decay, the discovery of this system has implications for the number of compact binary black holes that might be detectable sources of gravitational radiation. [show more]
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Creator:Legacy Astronomical Images Series:Galactic Sources Series Unit:Supernova Remnants Unit Type:Legacy Astronomical Image |
Description:This is a 3-color image of the region surrounding the W28 supernova remnant (SNR) that is located in our Galaxy. In this image blue=Very Large Array (VLA) 90cm, red=MSX 8 microns, and green=Southern Galactic Plane Survey + VLA 20cm data. This image was created to look for new supernova remnants through their non-thermal (synchrotron) radio emission. Non-thermal sources in these images are primarily blue in color, while massive star forming regions composed of thermal ionized hydrogen gas are white to cyan; warm thermal dust emission is red. Including W28, two SNRs were previously known in this field of view, six new SNRs were discovered from this image.
The VLA 90cm data is composed of B, C, and D configuration data and has a resolution of 42" (Brogan et al. 2006). The combined Southern Galactic Plane Survey (McClure-Griffiths et al. 2005) and VLA (Helfand et al. 2005) 20cm data has a resolution of 70" x 37". The MSX 8 micron data has a resolution of 20" (Price et al. 2001). [show more]
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Creator:Legacy Astronomical Images Series:Galactic Sources Series Unit:Supernova Remnants Unit Type:Legacy Astronomical Image |
Description:This is a 3-color image of the region surrounding the W30 supernova remnant (SNR) that is located in our Galaxy. In this image blue=Very Large Array (VLA) 90cm, red=MSX 8 microns, and green=Southern Galactic Plane Survey + VLA 20cm data. This image was created to look for new supernova remnants through their non-thermal (synchrotron) radio emission. Non-thermal sources in these images are primarily blue in color, while massive star forming regions composed of thermal ionized hydrogen gas are white to cyan; warm thermal dust emission is red. Previously, only the W30 SNR was known in this field of view, using this image we have discover two new ones.
The VLA 90cm data is composed of B, C, and D configuration data and has a resolution of 42" (Brogan et al. 2006). The combined Southern Galactic Plane Survey (McClure-Griffiths et al. 2005) and VLA (Helfand et al. 2005) 20cm data has a resolution of 70" x 37". The MSX 8 micron data has a resolution of 20" (Price et al. 2001). [show more]
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Creator:Legacy Astronomical Images Series:Galactic Sources Series Unit:Star Forming Regions Unit Type:Legacy Astronomical Image |
Description:These images show the W49A star forming region in context. The top image (Haslam, C. G. T., Salter, C. J., Stoffel, H., & Wilson, W. E. 1982, Astron. Astrophys. Suppl. Ser., 47, 1) shows the location of W49A in the galactic plane. The middle image shows the 3.6 cm emission from W49A. The image indicates the presence of a large number of HII regions in a small region of the sky. W49A is perhaps the best galactic example of starburst phenomena. The bottom image shows a detail 7 mm image of the most highly obscured region in W49A. None of the regions visible at 7 mm are detected at infrared or optical wavelengths, being deeply embedded in a molecular cloud. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Radio Galaxies Unit Type:Legacy Astronomical Image |
Description:VLA 20 cm map of radio source 3C 130, an elliptical galaxy in a distant cluster emitting two oppositely-directed narrow "jets" of radio emission from a small bright source in its nucleus. Such "twin-jet" sources are thought to arise when violent events in the nuclei of galaxies cause streams of particles moving almost at the velocity of light to break out of dense gas layers close to the center of the galaxy. Twin-jet nature of the sources may reflect flattened form of gas distribution in orbital motion around a central black hole in galactic nucleus. Studies of such jets at the VLA give clues to nature of energy transport from active central regions of galaxies to distant radio structures. This map shows inner faint jets opening into gently curved lobes, with radio core in central spot.
The VLA was in the "construction" configuration, using 13 antennas. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Seyferts Unit Type:Legacy Astronomical Image |
Description:This pseudo color image shows the structure of the 1.66 GHz emission from the radio source 3C120 as measured by the VLBA in June 1994. The resolution is 0.015 by 0.007 arcseconds with the higher resolution in the east-west direction. The radio jet is seen extending from the bright core region, where the energy is presumably generated, to about 0.5 arcseconds, or almost 1000 light years. Other observations with both VLBI and the VLA have shown this source to have emission on scales from significantly less than a light year to well over a million light years. The inner few light years of the jet have long been known to show motions of components at speeds faster than that of light. This is the well known "superluminal motion" seen in many bright, compact radio sources. No violation of relativity is involved, just a projection effect for a source moving near the speed of light almost directly toward the observer. Such motions are good evidence that the jet is relativistic (moving near the speed of light) so they give interesting information about the jet physics. It is not known how far from the central object (black hole by most models) the relativistic motion extends before it slows. This source is a good one to use to address this question because it is relatively close so motions can still be measured with the lower resolutions required to to see the structures far from the center. This image is one of a series made by R. C. Walker and collaborators to look at motions on scales of a few hundred light years. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Seyferts Unit Type:Legacy Astronomical Image |
Description:Radio image of the Seyfert galaxy 3C219. Radio features include an unresolved "core" at the center of the parent galaxy, a partial jet to the south-west, extended hot spots in both lobes and fine-scale filaments throughout the lobes. The redshift is 0.174 and the overall size of the radio source is about 370 kpc (for Hubble constant H=100 km/s/Mpc). The almost-circular shape of the hot spot in the northern lobe is unusual and its nature is controversial. The bright feature just to the north east of the galaxy is seen at higher resolution to be part of a counterjet structure. The difference in length and brightness between the main jet and the counterjet may be explained in terms of bulk motion at a velocity close to that of light in both features, although other interpretations are possible. The major features of this source are quite representative of structures seen in powerful radio galaxies -- elongated lobes filled with networks of filaments, bright hot spots near the outer parts of the lobes and a significant brightness asymmetry between the two jets.
VLA in A+B configuration using 27 antennas. Resolution of image is 1.3" x 1.2". [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Seyferts Unit Type:Legacy Astronomical Image |
Description:Radio image (red and yellow) is superimposed on an optical V-band field (blue). Radio features include an unresolved "core" at the center of the parent galaxy, a partial jet to the south-west, extended hot spots in both lobes and fine-scale filaments throughout the lobes. The parent galaxy is the brightest member of a compact cluster of which several other members are visible in the optical image. The redshift is 0.174 and the overall size of the radio source is about 370 kpc (for Hubble constant H=100 km/s/Mpc). The almost-circular shape of the hot spot in the northern lobe is unusual and its nature is controversial. The bright feature just to the north east of the galaxy is seen at higher resolution to be part of a counterjet structure. The difference in length and brightness between the main jet and the counterjet may be explained in terms of bulk motion at a velocity close to that of light in both features, although other interpretations are possible. The major features of this source are quite representative of structures seen in powerful radio galaxies -- elongated lobes filled with networks of filaments, bright hot spots near the outer parts of the lobes and a significant brightness asymmetry between the two jets.
VLA in A+B configuration using 27 antennas. Resolution of image is 1.3" x 1.2". [show more]
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Creator:Legacy Astronomical Images Series:Galactic Sources Series Unit:Supernova Remnants Unit Type:Legacy Astronomical Image |
Description:A radio image of the supernova remnant 3C58. The radio nebula is energized by a recently discovered pulsar. The beautiful filamentary structure of the nebula is brought out i this recent radio image, which was made using the NRAO Very Large Array telescope.
Image of 3C58 made using the A, B, and C array configurations of the VLA, which shows a wealth of new detail in this pulsar-powered supernova remnant. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Radio Galaxies Unit Type:Legacy Astronomical Image |
Description:20 cm pseudo-color VLA image of the radio source 3C 75 in the cluster of galaxies Abell 400. Red shows regions of intense radio emission, while blue shows regions of fainter emission The image consists of two twin jet radio sources associated with the binary nucleus of the central galaxy in Abell 400. The jets bend and appear to be interacting.
VLA in A-, C-, and D-configuration using 27 antennas. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Radio Galaxies Unit Type:Legacy Astronomical Image |
Description:6 cm VLA image of the interacting twin jet source associated with the central radio galaxy in Abell 400. The two red dots (bottom center of image) each are associated with one of the twin nuclei of the central galaxy in cluster of galaxies Abell 400. The jets are bent, possibly by the motion of hot gas in the cluster past the nuclei. On the right side of the image the two jets appear to interact and possibly are wrapped around one another.
VLA in B- and D-configuration using 27 antennas. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Seyferts Unit Type:Legacy Astronomical Image |
Description:The nucleus of the Seyfert galaxy NGC 1275 contains 3C84, one of the brightest, compact radio sources in the sky. This image is a pseudo color representation of the 22 GHz structure of 3C84 as measured using the VLBA and one VLA antenna in October 1995. The resolution is 0.00073 by 0.00043 arcseconds, with the higher resolution in the east-west direction. The total north-south extent of the emission shown is about 0.025 arcseconds or about 26 light years. The brightest regions just north of the center are the location of on-going energy production and probably correspond to the location of a massive black hole at the center of an accretion disk. The source underwent a large increase in brightness in about 1960 and, as VLBI measurements since the mid 1970's have shown, the southern feature has been expanding ever since at an apparent rate of about half the speed of light. The northern feature was not seen until recently and is still either absent or highly attenuated at lower frequencies. The attenuation is thought to be the result of absorption of the radiation by electrons associated with the accretion disk, which, because of the orientation of the system, only occults the far side, or northern, feature. This image is from a project that has used the VLBA to image the system at many frequencies to measure this absorption as a function of position. This will give valuable information on the electron content of the accretion region. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Seyferts Unit Type:Legacy Astronomical Image |
Description:VLBA images of 3C84 at multiple wavelengths, on scales of 0.05-5 parsecs, show (contour map A): a central core, an expanding bubble to the south (approaching us); a faint jet connecting the core to the bubble; and a northern (receding) counter-jet, seen through absorption by the accretion disk around the core. The 7mm images of the core show blobs of emission along a line with multiple bends, as if sprayed from a precessing nozzle. Components move at 0.05c, 0.08c, and 0.2c (where c = speed of light) at increasing distances along the jet, as if the blobs are accelerating away from the core. The slow-moving blobs brighten and dim as if a wave of brightening was moving down over them at a velocity of 0.9c. [show more]
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Creator:Legacy Astronomical Images Series:Miscellaneous Series Unit:Gamma-ray Bursters Unit Type:Legacy Astronomical Image |
Description:Artist's conception of the nearby gamma-ray burst of 29 March 2003 localized by NASA's HETE-2 satellite. Radio observations made with the Very Large Array, as well as the Australia Telescope Compact Array and the Ryle Telescope, have been combined with optical and X-ray data to show that this cosmic explosion had a nested jet structure (shown in the figure). The thin core of the jet produced weak gamma-rays while the thicker envelope produced copious radio waves. This information reveals that different types of cosmic explosions (gamma-ray bursts, X-ray flashes, and some type of supernovae) have the same amount of total energy and therefore share a common origin. In effect, different cosmic explosions are "beasts with different faces but the same body". [show more]
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Creator:Legacy Astronomical Images Series:Galactic Sources Series Unit:Star Forming Regions Unit Type:Legacy Astronomical Image |
Description:False color image of a star in making located in the Orion Nebula. The color represents the radio emission detected by the Very Large Array telescope using its most extended configuration, and thus allowed to reach a spatial resolution of about 20 AU. This image reveals its protoplanetary disk observed edge-on (the strongest clump, that has a size comparable to of our solar system) together with its outflow, that is perpendicular to the disk (the two faint clumps). In the right bottom corner is shown an artist's conception of this phenomenon.
This radio image was obtained from the project AZ154. In this project we mapped the OMC1 South region in the Orion nebula using the VLA in its "A" configuration at 7mm, getting thus an angular resolution of about 0.05". [show more]
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Creator:Legacy Astronomical Images Series:Galactic Sources Series Unit:Supernova Remnants Unit Type:Legacy Astronomical Image |
Description:W44 is one of the best example of an interacting supernova remnant with its parent molecular cloud. Radio continuum measurements indicate an elongated shell-like structure with a remarkable network of filaments and arcs across the face of this remnant (Giacani et al.1977). Recent near-IR, molecular hydrogen and 4.5 micron images using {Spitzer Space Observatory} show similar filamentary structure suggesting the presence of shocked molecular gas along the synchrotron-emitting radio filaments (Reach et al. 2006). X-ray observations show diffuse emission from the central region of this remnant (Rho et al. 1994). References: Reach, W. T., Rho, J. et al. 2006, AJ, 131, 1479 Rho, J., Petre, R., Schlegel, E. M., Hester, J. 1994, ApJ, 430, 757 Giacani, E. B., Dubner, G. M. et al. 1997, AJ, 113, 1379
A radio image in red color is constructed by the "author" from archival 20cm data by combining data from observations taken in the C and D-array configurations. The original radio image is published by Giacani et al. (1997). An X-ray image in blue color is based on ROSAT observations (Rho et al. 1994). An Infrared image in green color based on SPITZER observations (Reach et al. 2006) shows the distribution of molecular gas as the remnant interacts with its parent cloud. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Radio Galaxies Unit Type:Legacy Astronomical Image |
Description:Color composite image showing a wide angle tail radio galaxy, CWAT-01, and its environment discovered in the COSMOS field. The 20 cm continuum emission from its radio lobes (which is mainly due to synchrotron radiation of relativistic electrons) was observed with the VLA and is shown in white (bottom left part of the image). The B (blue), V (green) and i+ (red) band images, taken with the Subaru telescope, are shown in the background. These images show light observed in optical wavelengths which comes from foreground stars and stars in distant galaxies. Some of theses galaxies belong to the host cluster of CWAT-01. The X-ray emission of the galaxy clusters is shown in grey to red color gradients. It arises from bremsstrahlung of thermal electrons in the intra-cluster medium and was taken with the XMM-Newton satellite. Wide-angle tail galaxies are a special class of radio galaxies,usually found in galaxy clusters, whose radio jets are bent into a wide "C" shape. Their morphology suggests that they strongly interact with their external environment. Such galaxies are often found in merging cluster systems. The wide angle tail galaxy CWAT-01 is part of a very complex galaxy cluster assembly consisting of at least four X-ray luminous clusters at a redshift of z=0.2. This cluster system is presumably in the process of forming a large cluster having a minimum mass of about 20 percent of the Coma cluster mass.
Color composite image showing a wide angle tail radio galaxy, CWAT-01, and its environment discovered in the COSMOS field. The SUBARU B (blue), V (green), and i+ (red) bands are displayed in the background. The diffuse X-ray emission (i.e. the wavelet reconstruction of the 0.5-2 keV band image observed with XMM-Newton) is presented by grey to red color gradients. The 1.4 GHz map (obtained using the VLA) is shown in white. The image encompasses an area of 10'x8' which corresponds to approximately (2.1x1.7) squared Mpc at the galaxy clusters' redshift of z=0.2. North is towards the top of the image and east towards left. CWAT-01 is part of a very complex galaxy cluster assembly consisting of at least four X-ray luminous clusters at the same redshift. This cluster system is presumably in the process of forming a large cluster. Using the total masses of the individual clusters obtained from the X-ray spectral analysis we estimate that the final single cluster after the individual clusters merge will have a minimum mass of about 20 percent of the Coma cluster mass. Details about this radio galaxy and cluster assembly can be found in Smolcic et al. 2006. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Seyferts Unit Type:Legacy Astronomical Image |
Description:Artist's rendition of the accretion disk and radio jet around the black hole in the heart of the Seyfert galaxy NGC 4258. NGC4258 contains one of the very few galactic nuclei for which astronomers can make images of accretion disk material that lies within a few tenths of a parsec from a supermassive black hole. The most remarkable characteristics of the disk are that it is "paper thin," warped, and rotating differentially according to Kepler's laws (i.e., the square of rotation velocity is proportional to the reciprocal of radius). In many other galaxies the characteristics of accretion disks must be inferred indirectly. In NGC4258, they may be inferred directly from images that resolve the velocity and angular structure of the disk. In this artist's conception, the disk is color coded according to Doppler shift. The blue regions of the disk are moving toward us, while the red regions move away from us. The inset at the bottom of the graphic is a radio spectrum (intensity as a function of frequency or velocity) of the water maser emission. It is the distribution of water emission on the sky that astronomers map as they trace the outlines of the disk. The white glints on the disk surface show the locations of regions where maser emission has been detected. The blue beam emerging from the black hole represents the relativistic jet that has also be detected by astronomers on a variety of angular scales, with instruments such as the Very Large Array and the Very Long Baseline Array. It lies right along the rotation axis of the innermost portion of the disk, just as predicted by astronomical theory. Some theories predict that the black hole will be surrounded by a small region of radio-bright, intensely hot gas. In a challenge to these suggestions, so far none has been detected as astronomers have use techniques akin to adaptive optics to make very sensitive images of the region close to the black hole, and the hunt continues. [show more]
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Other Active Galactic Nuclei Unit Type:Legacy Astronomical Image |
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Creator:Legacy Astronomical Images Series:Active Galactic Nuclei Series Unit:Quasars Unit Type:Legacy Astronomical Image |
Description:Superluminal motion in quasar 3C279 is shown in a "movie" mosaic of five radio images made over seven years. The stationary core is the bright red spot to the left of each image. The observed location of the rightmost blue-green blob moved about 25 light years from 1991 to 1998, hence the changes appear to an observer to be faster than the speed of light or "superluminal". The motion is not really faster than light, the measured speed is due to light-travel-time effects for a source moving near the speed of light almost directly toward the observer. The blue-green blob is part of a jet pointing within 2 degrees to our line of sight, and moving at a true speed of 0.997 times the speed of light. These five images are part of a larger set of twenty-eight images made with the VLBA and other radio telescopes from 1991 to 1997 to study the detailed properties of this energetic quasar. [show more]
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Creator:Legacy Astronomical Images Series:Solar System Series Unit:Planets Unit Type:Legacy Astronomical Image |
Description:This is a radar image of the planet Venus made by transmitting a signal at 13 cm wavelength from Arecibo and using the GBT to detect the reflection off its surface. Brighter parts of the image indicate a rougher surface, while dark regions are smoother (on centimeter to meter scales). Many features, including mountain ranges, volcanic domes, and craters can be seen.
The resolution of this image varies from 1 to 5 km. [show more]
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Creator:Legacy Astronomical Images Series:Galaxies Series Unit:Peculiar Unit Type:Legacy Astronomical Image |
Description:A composite image of the optical light (green and yellow) and cold atomic hydrogen gas (blue) in the peculiar galaxy Arp 299, also known as NGC 3690/IC 694. Arp 299 is the result of two spiral galaxies which are in the process of colliding and merging into a single object. The atomic hydrogen observations (shown in blue in the image), taken with the Very Large Array, reveal a tremendous HI tail extending 55,000 light years (180 kiloparsecs) from the main bodies of the merging galaxies (see also this alternative version of these same data). Curiously, the gas tail is displaced from the optical tail (green in the figure), an unexpected and presently unexplained phenomena.
VLA C+D array observations with a resolution of 20". Optical image is a B-band image obtained with the University of Hawai'i's 88" telescope. A discussion of possible explanations for the optical/gaseous offsets can be found in Hibbard, Vacca & Yun 2000 (AJ, 119, 1130). [show more]
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Creator:Legacy Astronomical Images Series:Galactic Sources Series Unit:Stars Unit Type:Legacy Astronomical Image |
Description:Artist Conception of Dusty Disk Around Young Star
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Creator:Legacy Astronomical Images Series:Galaxies Series Unit:Peculiar Unit Type:Legacy Astronomical Image |
Description:A composite image of the optical light (green), warm gas (pinkish white), and cold atomic hydrogen gas (blue) in the well known interacting pair of galaxies known as "The Mice", or NGC 4676. The nickname of this object derives from its optical appearance, specifically the narrow tails emering from oval shaped bodies, reminiscent of two mice . This system is the result of two spiral galaxies which are falling together. As computer simulations demonstrate, the tidal tails are thrown out after the galaxies pass each other once and are pulled together by their mutual gravitational attraction. The tails emerge from the far side of the disks, which is pulled less than the other parts of the galaxy. The tails are, in effect, the material that gets "left behind" as the galaxies fall back together. The atomic hydrogen observations, taken with the VLA in its C- and D-array configurations, show the tidal tails to be rich in cold gas, confirming the gas-rich nature of the progenitor disks. The warm gas, as mapped in the Halpha line emission, is likely heated by the young massive stars in star forming regions. There are numerous such regions distributed all along the tails, which may seed the formation of small stellar systems, and possibly even distinct dwarf galaxies.
VLA C+D array observations with a resolution of 30". Optical image is an B-band image, and both this image and the continuum subtracted Halpha image were obtained with the KPNO 2.1m telescope. [show more]
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Creator:Legacy Astronomical Images Series:Galaxies Series Unit:Peculiar Unit Type:Legacy Astronomical Image |
Description:Composite image of the nearest Ultraluminous Infrared Galaxy (ULIG), Arp 220. The image shows the optical starlight depicted in green, yellow, and orange, with the neutral atomic hydrogen gas depicted in blue. ULIGs emit more energy in the Infrared than at any other wavelength. This energy arises from a powerful dust-enshrouded starburst, believed to be triggered when two galaxies smash together. The dust is heated by the UV light emitted by the young, hot stars made in the starburst, and re-radiate this energy at infrared wavelengths. The peculiar optical morphology of this system supports the idea that Arp 220 is the result of two galaxies merging into one, and the neutral atomic gas in the outer regions indicates that the galaxies which merged were gas-rich spiral galaxies. There is actually not a hole in the atomic gas distribution; the central gas is absorbed against a bright central radio continum source (not shown) so it is not seen in emission.
VLA C+D array observations at 30" resolution. Optical image is a 900 sec R-band observation with the University of Hawai'i 88" telescope obtained in June 1995. [show more]
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