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Titolo:
A detailed analysis of a Cygnus Loop shock-cloud interaction

Autore:

Indirizzi:: Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA Johns Hopkins Univ Baltimore MD USA 21218 Astron, Baltimore, MD 21218 USA Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA Harvard Smithsonian Ctr Astrophys Cambridge MA USA 02138 ge, MA 02138 USA
Titolo Testata:: ASTRONOMICAL JOURNAL
fascicolo: 2, volume: 122, anno: 2001,
pagine: 938 - 953
SICI:: 0004-6256(200108)122:2<938:ADAOAC>2.0.ZU;2-L
Fonte:: ISI
Lingua:: ENG
Soggetto:: HOPKINS-ULTRAVIOLET-TELESCOPE; X-RAY; SUPERNOVA REMNANT; INTERSTELLAR CLOUDS; IMAGING TELESCOPE; FE-X; EMISSION; WAVE; FILAMENT;
Keywords:: planetary nebulae : general; supernova remnants;
Tipo documento:: Article
Natura:: Periodico
Settore Disciplinare:: Physical, Chemical & Earth Sciences
Citazioni:: 39
Recensione:
Indirizzi per estratti:: Indirizzo: Danforth, CW Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA Johns Hopkins Univ 3400 N Charles St Baltimore MD USA21218 A



Citazione:: C.W. Danforth et al., "A detailed analysis of a Cygnus Loop shock-cloud interaction", ASTRONOM J, 122(2), 2001, pp. 938-953

Abstract

The XA region of the Cygnus Loop is a complex zone of radiative and nonradiatve shocks interacting with interstellar clouds. We combine five far ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT),a grid of 24 IUE spectra, and a high-resolution long-slit H alpha spectrumto study the spatial emission line variations across the region. These spectral data are placed in context using ground-based optical emission-line images of the region and a far-UV image obtained by the Ultraviolet Imaging Telescope (UIT). The presence of high-ionization species (O VI, N V, and C IV) indicates a shock velocity near 170 km s(-1) while other diagnostics indicate km s(-1). It is likely that a large range v(sh) approximate to 140 of shock velocities may exist at a spatial scale smaller than we are able toresolve. By comparing C IV lambda 1550, C III lambda 977, and C III] lambda 1909, we explore resonance scattering across the region. We find that a significant column depth is present at all positions, including those not near bright optical or UV filaments. Analysis of the O VI doublet ratio suggests an average optical depth of about unity in that ion, while flux measurements of [Si VIII] lambda 1443 suggest a hot component in the region at just below 10(6) K. Given the brightness of the O VI emission and the age of the interaction, we rule out the mixing-layer interpretation of the UV emission. Furthermore, we formulate a picture of the XA region as that of an encounter of the blast wave with a finger of dense gas protruding inward from the pre-supernova cavity.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/06/13 alle ore 23:25:23