Monday, February 27, 2006
Sunday, February 12, 2006
These images represent views of Kepler's supernova remnant taken in X-rays, visible light, and infrared radiation.
Each top panel shows the entire remnant. Each color in this image represents a different region of the electromagnetic spectrum, from X-rays to infrared light. The X-ray and infrared data cannot be seen with the human eye. Astronomers have color-coded those data so they can be seen in these images.
The bottom panels are close-up views of the remnant. In the bottom, center image, Hubble sees fine details in the brightest, densest areas of gas. The region seen in these images is outlined in the top, center panel.
The three lower panels highlight several regions of interest within the ELAIS-N1 field.
The Tadpole galaxy (bottom left) is the result of a recent galactic interaction in the local universe. Although these galactic mergers are rare in the universe's recent history, astronomers believe that they were much more common in the early universe. Thus, SWIRE team members will use this detailed image of the Tadpole galaxy to help understand the nature of the "faint red-orange specks" of the early universe.
The middle panel features an unusual ring-like galaxy called CGCG 275-022. The red spiral arms indicate that this galaxy is very dusty and perhaps undergoing intense star formation. The star-forming activity could have been initiated by a near head-on collision with another galaxy.
The most distant galaxies that SWIRE is able to detect are revealed in a zoom of deep space (bottom right). The colors in this feature represent the same objects as those in the larger field image of ELAIS-N1.
Saturday, February 11, 2006
This false-color image from NASA's Spitzer Space Telescope reveals hidden populations of newborn stars at the heart of the colliding "Antennae" galaxies. These two galaxies, known individually as NGC 4038 and 4039, are located around 68 million light-years away and have been merging together for about the last 800 million years. The latest Spitzer observations provide a snapshot of the tremendous burst of star formation triggered in the process of this collision, particularly at the site where the two galaxies overlap.
The newly revealed infant stars appear as pink and red specks toward the center of the combined IRAC-MIPS image (left panel). The stars appear to have formed in regularly spaced intervals along linear structures in a configuration that resembles the spokes of a wheel or the pattern of a snowflake. Hence, astronomers have nicknamed this the "Snowflake Cluster."
Star-forming clouds like this one are dynamic and evolving structures. Since the stars trace the straight line pattern of spokes of a wheel, scientists believe that these are newborn stars, or "protostars." At a mere 100,000 years old, these infant structures have yet to "crawl" away from their location of birth. Over time, the natural drifting motions of each star will break this order, and the snowflake design will be no more.
This "tornado," designated Herbig-Haro 49/50, is shaped by a cosmic jet packing a powerful punch as it plows through clouds of interstellar gas and dust.
The tornado-like feature is actually a shock front created by a jet of material flowing downward through the field of view. A still-forming star located off the upper edge of the image generates this outflow. The jet slams into neighboring dust clouds at a speed of more than 100 miles per second, heating the dust to incandescence and causing it to glow with infrared light detectable by Spitzer. The triangular shape results from the wake created by the jet's motion, similar to the wake behind a speeding boat.
HH 49/50 is located in the Chamaeleon I star-forming complex, a region containing more than 100 young stars. Most of the new stars are smaller than the sun, although some are more massive. Visible-light observations have found a number of outflows in the region, however most of those outflows have no infrared counterpart.