An Atlas of ASCA Supernova Remnants

  1. Copyright Notice
  2. Naming Convention
  3. Images
  4. Acknowledgments

I. Copyright Notice

The author grants permission to reproduce part or all of the images maintained on this site for non-commercial educational use as long as photo credit is displayed.

II. Naming Convention [Top]

  • The official "G" name for a SNR is used in this catalog when available. For those SNRs whose "G" name is not yet defined, one is assigned herein based on the coordinate of the center of the SNR, as determined by visual inspection.

  • The Right Ascension and Declination for a SNR are resolved through the SIMBAD database, if available. For those SNRs which are not included in the SIMBAD database (i.e., G259+), the NED database is used instead.

  • Common Names were also found through SIMBAD, though in many cases, not all of the names have been listed.

    III. Images [Top]

  • ASCA SNR images were generated using screened data obtained from the ASCA public archive (REV2 version).

  • Each image is centered on the named SNR; the center of the SNR is determined by visual inspection. However, the listed Right Ascension and Declination are the coordinates resolved using either the SIMBAD or NED database.

  • Exposure maps were generated for each image using ascaexpo with a maximum attitude deviation of 4 and an image rebining factor of 1 and 4, for the GIS and SIS respectively.

  • Matching broad- and narrow-band sky images were generated in four energy bands using PI-channel cuts corresponding to energy ranges of 0.5-10.0 keV (broad-band), 0.5-2.5 keV (soft), 2.5-5.5 keV (med), 5.5-10.0 keV (hard), . For the SIS instrument these PI-channel cuts are 137-1708, 137-684, 685-1264, and 1265-1708, for broad, soft, med, hard energy-bands, respectively. The corresponding PI-channel cuts for the GIS instrument are 42-839, 42-209, 210-460, 461-839.

  • The coordinates of all ASCA images on this web site have been updated using the method described in the ASCA coordinate correction web-page using the July 28, 2000 version of the offset coordinate table.

  • The ASCA sky images and exposure maps for each SNR were smoothed using a 3 and 5 element box-car filter, for the GIS and SIS instruments respectively. The final SNR image file is produced by dividing the summed sky image by its respective exposure map. In the resulting image, pixels values were set to zero if the exposure for this pixel were less then 3 per-cent (typically) of the maximum exposure.

  • GIF images were produced using the pgplot plotting subroutine package, called from a FORTRAN program. Most of the SNRs are scaled linearly, however, on occasion, a logarithmic scaling is used (e.g. W50).

  • A few GIS observation was taken in mixed image-size mode; instead of the default 256x256 pixel image mode, data were collected using 64x64 pixels. For these cases, the 256x256 and the 64x64 pixel images were generated separately and the image for which the exposure time is greatest was used in the Atlas.

    IV. Acknowledgments [Top]

    This site is dedicated to the exceptional creativity, talent, and hard work of all the members of the ASCA engineering and scientific teams that has made ASCA a remarkably successful mission.

    The author is indebted to the able assistance of Vanessa Yuille in constructing this website.

    We would like to acknowledge D. A. Green's Catalogue of Galactic Supernova Remnants as a source of information and suggestions for this atlas.

    This research has made use of data obtained through the High Energy Astrophysics Science Archive Research Center Online Service, provided by the NASA/Goddard Space Flight Center.

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