X-ray Astronomy

The astmosphere is opaque to X- rays (good thing, too!)

This ROSAT PSPC false-color image is of a portion of a nearby stellar wind superbubble (the Orion-Eridanus Bubble) stretching across Eridanus and Orion.Eridanus Orion Soft X-rays are emitted by hot gas (T ~ 2-3 MK) in the interior of the superbubble. This bright object forms the background for the "shadow" of a filament of gas and dust. The filament is shown by the overlaid contours, which represent 100 micron emission from dust at a temperature of about 30 K as measured by IRAS. Here the filament absorbs soft X-rays between 100 and 300 eV, indicating that the hot gas is located behind the filament. This filament may be part of a shell of neutral gas that surrounds the hot bubble. Its interior is energized by UV light and stellar winds from hot stars in the Orion OB1 association. These stars energize a superbubble about 1200 lys across which is observed in the optical (Hα) and X-ray portions of the spectrum.IRAS

Chandra X- ray Observatory inside the Space Shuttle payload bay

Three structures around Eta Carinae are thought to represent shock waves produced by matter rushing away from the superstar at supersonic speeds.Eta Carinae The temperature of the shock-heated gas ranges from 60 MK in the central regions to 3 MK on the horseshoe-shaped outer structure. "The Chandra image contains some puzzles for existing ideas of how a star can produce such hot and intense X-rays," says Prof. Kris Davidson of the University of Minnesota.[21] Davidson is principal investigator for the Eta Carina observations by Hubble. "In the most popular theory, X-rays are made by colliding gas streams from two stars so close together that they'd look like a point source to us. But what happens to gas streams that escape to farther distances? The extended hot stuff in the middle of the new image gives demanding new conditions for any theory to meet."University of Minnesota[21]

Appropriately Appropriately famous for its broad ring of obscuring dust and hat-like appearance, the Sombrero Galaxy (aka spiral galaxy M104) is featured in this unique composite view that spans the electromagnetic spectrum, from three major space- based observatories.spiral galaxy M104unique composite view electromagnetic spectrum Exploring the Sombrero's high-energy x-ray emission (blue), the Chandra contribution highlights the pervasive, tenuous, hot gas that extends some 60,000 light-years from the galaxy's center. Hubble's optical view (green) shows the more familiar emission from the Sombrero's population of stars, seen from a nearly edge-on perspective and noticeably bulging at the galaxy's bright core. The broad ring of dust that blocks light in other bands, glows in the infrared contribution (red) from the Spitzer Space Telescope. The Sombrero Galaxy is about 28 million light-years away, near the southern edge of the extensive Virgo cluster of galaxies.Chandra contribution Hubble's opticaledge-onSpitzer Space TelescopeVirgo cluster

X-ray Mirror

Major questions in X-ray astronomy Stellar magnetic fields Extrasolar X-ray source astrometry Solar X-ray astronomy: –Coronal heating problem –Coronal mass ejection

X-rays can also be used for spectroscopy: What are the atoms ? X-rays penetrate, and are much smaller than light New instruments called "micro calorimeters" are being developed which will be able to resolve individual lines which make up a single peak with today's spectrometers. With this higher spectral resolution, the strengths of lines that are much closer together in wavelength will be able to be used to compute conditions in the remnant such as temperature and density. With the help of these new instruments we will be able to say with greater confidence what the progenitor stars were made of and what the conditions of the remnant are like now.spectrometers