Ultraviolet absorption lines associated with the Vela supernova remnant

Journal Article · Wed Dec 01 04:00:00 EST 1976 · Astrophys. J., Suppl. Ser.; (United States)

DOI:https://doi.org/10.1086/190412· OSTI ID:7316928

Jenkins, E B; Silk, J; Wallerstein, G

Two stars behind the Vela supernova remnant and two stars offset from the remnant have been observed. Over 200 interstellar atomic and molecular absorption features between 1000 and 1400 A have been identified and measured for radial velocity and equivalent width. In many cases, additional information was obtained by studying the detailed shapes of the recorded profiles. Most of the stars show several absorption components, with clouds of the highest radial velocity appearing in the spectra of stars behind the remnant. For each component, column densities were derived. Qualitatively, the gas toward the remnant exhibits a number of unusual properties. First, abnormally high radial velocities were evident: many ions were positively identified at velocities of -90 and -180 km s/sup -/1, and uncertain detections of O VI were apparent at -400 km s/sup -1/. Second, the degree of ionization of some elements, such as S and Si, suggested the existence of ionizing processes significantly more potent than those found in general regions of space. The distribution of H/sub 2/ in different rotational states toward one star tends to corroborate this conclusion. Finally, an investigation of electron densities shows that much of the gas, especially that at high velocity, must exist in the form of relatively thin sheets or filaments. Other observations have demonstrated that the region near these stars is characterized by a large network of nebulosities having a complicated filamentary appearance, unusually strong soft x-ray emission, and emission of (Fe XIV). In addition, many other stars in this area show high-velocity interstellar Ca II absorption lines. It is evident that we are viewing a region of the sky containing highly disturbed gas. Moreover, we interpret the results as an indication that a shock from the Vela supernova explosion has interacted with a volume containing large density fluctuations (i.e., a cloudy medium) rather than a uniform distribution of gas.

• Research Organization: Princeton University Observatory
• OSTI ID: 7316928
• Journal Information: Astrophys. J., Suppl. Ser.; (United States), Journal Name: Astrophys. J., Suppl. Ser.; (United States) Vol. 32:4; ISSN APJSA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
ABUNDANCE
CHEMICAL COMPOSITION
COSMIC GASES
COSMIC RADIO SOURCES
ENERGY-LEVEL TRANSITIONS
EXCITATION
FINE STRUCTURE
FLUIDS
FUNCTIONS
GASES
INTERSTELLAR SPACE
IONIZATION
LINE WIDTHS
RADIAL VELOCITY
SHOCK WAVES
SPACE
SPECTRA
SPECTRAL DENSITY
SPECTRAL FUNCTIONS
SUPERNOVA REMNANTS
ULTRAVIOLET SPECTRA
VELOCITY