Year: 1999
Type: article
Abstract: Observations of the oxygen lines [O II] 3729 Å and [O III] 5007 Å in the medium immediately beyond the Cygnus Loop supernova remnant were carried out with the scanning Fabry-Pérot spectrophotometer Experience Spectroscopique d'Observation des Plasmas (ESOP). Both lines were detected in three different directions (east, northeast, and southwest), and up to a distance of 15 pc from the shock front. The ionized medium is in the immediate vicinity of the remnant, as evinced by the smooth brightening of both lines as the adiabatic shock transition (defined by the X-ray perimeter) is crossed. These lines are usually brighter around the Cygnus Loop than in the general background in directions where the Galactic latitude is ≥5°. There is also marginal (but significant) evidence that the degree of ionization is somewhat larger around the Cygnus Loop. We conclude that the energy necessary to ionize this large bubble of gas could have been supplied by an O8 or O9 type progenitor, or by the particles heated by the expanding shock front. The second possibility, although highly attractive, would have to be assessed by extensive modeling.
Source: The Astrophysical Journal
DOI: 10.1086/307247
Authors: Joaquin Bohigas, Jean Luc Sauvageot, Anne Decourchelle
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1974699166