Spitzer IRS observations of the XA region in the cygnus loop supernova remnant
- SOFIA Science Center, NASA Ames Research Center, M/S N211-3, Moffett Field, CA 94035 (United States)
- Smithsonian Astrophysical Observatory, 60 Garden Street, MS 15, Cambridge, MA 02138 (United States)
- Department of Physics, Western Michigan University, Kalamazoo MI 49008-5252 (United States)
- Goddard Space Flight Center, Mail Code 662, Greenbelt, MD 20771 (United States)
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)
- North Carolina State University, Raleigh, NC 27607 (United States)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
We report on spectra of two positions in the XA region of the Cygnus Loop supernova remnant obtained with the InfraRed Spectrograph on the Spitzer Space Telescope. The spectra span the 10-35 μm wavelength range, which contains a number of collisionally excited forbidden lines. These data are supplemented by optical spectra obtained at the Whipple Observatory and an archival UV spectrum from the International Ultraviolet Explorer. Coverage from the UV through the IR provides tests of shock wave models and tight constraints on model parameters. Only lines from high ionization species are detected in the spectrum of a filament on the edge of the remnant. The filament traces a 180 km s{sup –1} shock that has just begun to cool, and the oxygen to neon abundance ratio lies in the normal range found for Galactic H II regions. Lines from both high and low ionization species are detected in the spectrum of the cusp of a shock-cloud interaction, which lies within the remnant boundary. The spectrum of the cusp region is matched by a shock of about 150 km s{sup –1} that has cooled and begun to recombine. The post-shock region has a swept-up column density of about 1.3 × 10{sup 18} cm{sup –2}, and the gas has reached a temperature of 7000-8000 K. The spectrum of the Cusp indicates that roughly half of the refractory silicon and iron atoms have been liberated from the grains. Dust emission is not detected at either position.
- OSTI ID:
- 22356890
- Journal Information:
- Astrophysical Journal, Vol. 787, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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