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More Information

Blasts From The Past: Historic Supernovas

  Flash from Chandra.

Additional Information for Teachers:

1. Depending upon your classroom, you may decide to use the pencil and paper version of the X-Ray Spectroscopy of Supernova Remnants activity before using the ds9 image analysis software version for the Tycho and G292.0+1.8 remnants. This will give students the opportunity to learn how to identify emission lines and match them with the appropriate elements; the ds9 version can then be utilized to analyze the supernova remnants in the Extension list.

Studying a SNR's spectrum is the most direct way of determining the composition of the progenitor star. In young remnants that have not yet swept up a significant amount of interstellar gas, the imprint of the stellar ejecta on the remnant's spectrum is strong, so the spectrum can tell us a lot about the material that made up the progenitor star. The observed elements and abundances are very different for different type of SN explosions (massive star vs. white dwarf). Type Ia remnants (from white dwarfs) should have relatively strong Si, S, Ar, Ca, and Fe, and weak O, Ne, and Mg; Type II (from massive stars) generally have the reverse pattern.

OBS ID 115 (Tycho's SNR) - Type Ia

XMM Newton

OBS ID 126 (G292.0+1.8) - Type II
Tycho's observations
Hughes, et all 2001.

Note the higher abundance
of O, Ne, and Mg in this
Type II spectrum.

Tycho's observations

Use Analysis>Chandra Ed Analysis Tools>Energy Cut in ds9 to view the location of only the high energy or "hard" x-ray photons (a "lo" of 4 KeV and a "hi" of 8 KeV). in this SNR. You can see the results in the frame on the right. This shows the region that could be the core remnant pointing to a type II supernova from a massive star.

2. Information for the supernova remnants listed in number 1(a through e) in the Extensions Section.

OBS ID 117 (W49B) - Type II; though hard to tell from the spectrum perhaps due to interstellar absorption of lines less than 1.5 keV ( so you can't see O, Me and Mg lines). From this spectrum it is very difficult to classify the supernova type. Students may say it is a type Ia if they do no further research.

OBS OD 116 - Type?; Astronomers have studied Kepler intensively over the past three decades with radio, optical and X-ray telescopes, but its origin has remained a puzzle. On the one hand, the presence of large amounts of iron and the absence of a detectable neutron star points toward a Type Ia supernova. On the other hand, when viewed in optical light, the supernova remnant appears to be expanding into dense material that is rich in nitrogen. This would suggest Kepler is a Type II supernova event as Type Ia supernovas do not normally have such surroundings.

OBS ID 2758 (SNR 0103-72.6) - Type II; Oxygen and neon are the most abundant elements in the spectrum as in the spectrum of G292.0+1.8. In ds9, using color>bb and scale>square root, you can also see (faintly) a core remnant.

Obs ID 775 (DEM L71) - Type 1a; O and Ne are not evident in the spectrum (which could be due to interstellar absorption BUT there also does not seem to be a core remnant as in a type II). Other elements are similar to those of Tycho's SNR.

Obs ID 114 (Cas A) - Type II; Spectrum has a peak at Ne, but O and Mg are either missing or not very prominent. Spectrum looks very much like that of Tycho's SNR. A bright core, however, is evident at the center of the image. Interstellar absorption may be responsible for not seeing emission lines less than 1.5 KeV.

3. References that can be used for further discussion and study of the classification of supernova remnants.

Typing supernovae from their remnants

X-ray Spectroscopy of Young SNR - Imagine! The Universe

An X-Ray Study of the Supernova Remnant G290.1-0.8

The X-Ray Line Emission from the Supernova Remnant W49B

0103-72.6: A New Oxygen-Rich Supernova Remnant in the Small Magellanic Cloud

Iron-rich Ejecta in the Supernova Remnant DEM L71

HST Observations of SNRs in Magellanic Clouds. II.

ASCA X-Ray Spectroscopy of Large Magellanic Cloud Supernova Remnants and the Metal Abundances of the Large Magellanic Cloud

Young Supernova Remnants in the Magellanic Clouds

Hughes Presentation on X-ray studies of SNR