The gold color of the background is a monochromatic optical image. All the color in the remnant is x-ray data, mapped as red, 0.5-1.5 keV; green, 1.5-2.5 kev; blue 4.0-6.0 kev. These are soft x-rays in the ~1 nm wavelength range. I assume these are thermal x-ray emissions, but there are other ways that x-rays can be produced, so the analysis might be somewhat more complex than simply understanding red to represent cooler material than blue.MarkBour wrote:I am wondering what the false colors represent.
The nominal expansion velocity of the shell is 5500 km/s, with isolated knots of material moving at higher speeds. Any analysis is also complicated by the fact that the expansion isn't symmetrical, and any glowing material (especially fast knots) is probably slowing down due to shock effects. Still, the nominal speed is consistent with 300 years since the explosion and a shell diameter of 11 ly (which is more often given than 15 ly).I read a short article on the Chandra site (from the "supernova remnant" link) that mentions supernovas like this one ejecting matter at about 50 million km/hr. At that rate, if it were constant, in about 350 years, the debris would spread to a radius of 15 light years. I wonder if the spreading field slows down. If not, then since the ball seems to have a diameter of 15 ly, rather than a radius of 15 ly, perhaps this material was ejected more slowly, like at 25 million km/hr.
