Penn State Dept. of Astronomy & Astrophysics

X-ray Shadow GIF Catalog

The images shown here are false-color X-ray images from the ROSAT satellite overlaid with contour maps of the 100 micron infrared emission from the IRAS satellite. The IRAS satellite mapped the entire sky, but we show a small region of about 3 degrees square in these images. The ROSAT Position Sensitive Proportional Counter (PSPC) had a circular field of view of about 1 degree radius, within which we have represented the X-ray surface brightness by color, with the faintest regions indicated by blue and the brightest by white (the colors are arranged in order of the rainbow: blue-green-read-white). Several of the X-ray fields are not circular; this is because several slightly offset pointings were combined for these images. The X-ray images trace hot gas in the interstellar medium, while the infrared contours trace cold dust (which is usually associated with cold gas). A comparison of the X-ray images and 100 micron contours reveals which features in the X-ray images are due to absorption of the X-rays by the cold gas/dust. We can study these shadows to learn more about the cold gas/dust in the absorbing cloud, and to learn more about the distribution of hot gas in our galaxy.

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Chamaeleon I Dark CloudChamaeleon I Dark Cloud

This image shows a ROSAT PSPC false-color image of the Chamaeleon I dark cloud, a well-known site of star formation.
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Draco NebulaDraco Nebula

This image shows a ROSAT PSPC false-color image of the deepest portion of the soft X-ray shadow of the high latitude cometary cloud known as the Draco nebula.
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R Corona AustralisR Corona Australis

This image shows a ROSAT PSPC false-color image of the R Cr A molecular cloud. Unlike most other soft X-ray shadows discovered to date, which absorb strongly in either the 1/4 keV or 3/4 keV energy band but not in both, R Cr A has strong absorption at both energies.

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Orion-Eridanus Bubble Orion-Eridanus Bubble

This image shows a ROSAT PSPC false-color image of a portion of a nearby stellar wind superbubble stretching across the constellations Eridanus and Orion and known as the Orion-Eridanus Bubble.

For more information about X-ray shadows research, contact David Burrows (burrows@astro.psu.edu) .
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Penn State's High Energy Astrophysics group web pages are maintained by Scott Koch.
Last update: December 16, 1997