Karl Isensee's CasA Stuff


Karl Isensee
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New CasA Prelim. Results (Aug. 06)

  • Below is the IR data that I have used. Each image has been convolved to either 4", 7" or 15" based on the wavelength.

    • The IR Data

  • IR Continuum at 9.7 microns
  • IR Continuum at 37 microns
  • SIV at 10.5 microns
  • SIII at 18 microns
  • SIII at 33 microns
  • SiII at 35 microns

    • Density Map (SIII_18 / SIII_33 ratio map)

    Difference Images

  • Below are a series of interesting difference images using both the X-Ray and IR data. Note that several regions are consistently brighter in either the IR or X-Ray. Also note how the various Sulfur and Silicon lines can show up relatively brightly at very different places in the remnant.

    Each image has had a small number added to it so that the background averages to 0 counts. Then, the number of counts in each image was forced to be the number of counts in the full spectrum X-Ray image. Finally, the images were subtracted from each other.
  • The X-Ray Sulfur line energy cut substracted from the X-Ray Silicon line cut
  • A 9.7 micron image subtracted from the full (.3-10 kev) X-Ray image
  • A 37 micron image subtracted from the full X-Ray image
  • SIII at 18 microns subtracted from the X-Ray sulfur line
  • SIII at 33 microns subtracted from the X-Ray sulfur line
  • SIV at 10.5 microns subtracted from the X-Ray sulfur line
  • SIII at 18 microns subtracted from SIII at 33 microns
  • SiII at 35 microns subtracted from the X-Ray silicon line
  • Sulfur at 33 microns subtracted from silicon at 35 microns

    • RGB Frames

  • RGB frame with red being X-Ray sulfur and green being X-Ray silicon. Note that the scales for the two colors might not be identical.
  • RGB frame with red being SIII at 18 microns, green being SIII at 33 microns, and blue being SIV at 10.5 microns. Once again, the scales for the colors are likely not identical.

    • Older CasA Prelim. Results (Mar. 06):

    Convolved 2000 Epoch image

    Convolved 2004 Epoch image

    The 2000 image subtracted from the 2004 image

    Notes:

  • Many of the differences in the images can be explained by the overall expansion of the object. This view is confirmed by the fact that many of the regions on the right of the difference image appear to integrate to 0, as would be expected for expanding objects that do not undergo brightness changes.
  • Some differences are not easily explained by expansion or any other phenomena associated with CasA that I know of. A good example of this is the region at about 10 0'Clock. Not only are the brightness changes nonradial, but they do not appear to integrate to 0. Also, it does not appear that the difference is one object moving. This was determined by blinking the 2000 and 2004 epoch images in ds9, but it is very uncertain. Interestingly, this region is very close to Patnaude's R1 knot, which shows the greatest overall brightness change from the 2000 to 2004 epochs. There are several other regions that appear to undergo brightness changes that cannot be explained by expansion. The overall "residuals" that you see in the difference images tend to be around 6-10% of the overall brightness of the regions in question.
  • There are, of course, problems with artifacts in the images, especially in the difference image. Thus, you have to raise the question of whether or not some of the differences between the epochs are real. Many of the effects right on the lines themselves are certainly not real, but I believe that many of the other differences are real. I will be performing several tests in the next couple of weeks to make sure that this view is correct. These tests will probably include using 2002 epoch images and normalizing the epochs with respect to one another in different ways to see if I can make the regions in question integrate to 0 with different scalings of the images.

    • Overview of Old Stuff (Summer 2005):

    Points of Interest/Problems:

    Figures (very much work in progress):