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تسجيل مستخدم جديدFar Ultraviolet Spectral Images of the Vela Supernova Remnant
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We present far-ultraviolet (FUV) spectral-imaging observations of the Vela supernova remnant (SNR), obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR) instrument, also known as FIMS. The Vela SNR extends 8 degrees in the FUV and its global spectra are dominated by shock-induced emission lines. We find that the global FUV line luminosities can exceed the 0.1-2.5 keV soft X-ray luminosity by an order of magnitude. The global O VI:C III ratio shows that the Vela SNR has a relatively large fraction of slower shocks compared with the Cygnus Loop.
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We present the improved far-ultraviolet (FUV) emission-line images of the entire Vela supernova remnant (SNR) using newly processed SPEAR/FIMS data. The incomplete C III {lambda}977 and O VI {lambda}{lambda}1032, 1038 images presented in the previous
study are updated to cover the whole region. The C IV {lambda}{lambda}1548, 1551 image with a higher resolution and new images at Si IV {lambda}{lambda}1394, 1403, O IV] {lambda}1404, He II {lambda}1640.5, and O III] {lambda}{lambda}1661, 1666 are also shown. Comparison of emission line ratios for two enhanced FUV regions reveals that the FUV emissions of the east enhanced FUV region may be affected by nonradiative shocks of another very young SNR, the Vela Jr. SNR (RX J0852.0-4622, G266.6-1.2). This result is the first FUV detection that is likely associated with the Vela Jr. SNR, supporting previous arguments that the Vela Jr. SNR is close to us. The comparison of the improved FUV images with soft X-ray images shows that a FUV filamentary feature forms the boundary of the northeast-southwest asymmetrical sections of the X-ray shell. The southwest FUV features are characterized as the region where the Vela SNR is interacting with slightly denser ambient medium within the dim X-ray southwest section. From a comparison with the H{alpha} image, we identify a ring-like H{alpha} feature overlapped with an extended hot X-ray feature of similar size and two local peaks of C IV emission. Their morphologies are expected when the H{alpha} ring is in direct contact with the near or far side of the Vela SNR.
We present the first far-ultraviolet (FUV) emission-line morphologies of the whole region of the supernova remnant (SNR) G65.3+5.7 using the FIMS/SPEAR data. The morphologies of the C IV {lambda}{lambda}1548, 1551, He II {lambda}1640, and O III] {lam
bda}{lambda}1661, 1666 lines appear to be closely related to the optical and/or soft X-ray images obtained in previous studies. Dramatic differences between the C IV morphology and the optical [O III] {lambda}5007 image provide clues to a large resonant-scattering region and a foreground dust cloud. The FUV morphologies also reveal the overall distribution of various shocks in different evolutionary phases and an evolutionary asymmetry between the east and the southwest sides in terms of Galactic coordinates, possibly due to a Galactic density gradient in the global scale. The relative X-ray luminosity of G65.3+5.7 to C IV luminosity is considerably lower than those of the Cygnus Loop and the Vela SNRs. This implies that G65.3+5.7 has almost evolved into the radiative stage in the global sense and supports the previous proposal that G65.3+5.7 has lost its bright X-ray shell and become a member of mixed-morphology SNRs as it has evolved beyond the adiabatic stage.
We report a Far Ultraviolet Spectroscopic Explorer satellite observation of the supernova remnant N49 in the Large Magellanic Cloud, covering the 905 -- 1187 A spectral region. A 30 square aperture was used, resulting in a velocity resolution of ~100
km/s. The purpose of the observation was to examine several bright emission lines expected from earlier work and to demonstrate diffuse source sensitivity by searching for faint lines never seen previously in extragalactic supernova remnant UV spectra. Both goals were accomplished. Strong emission lines of O VI 1031.9 A, 1037.6 A and C III 977.0 A were seen, Doppler broadened to +/- 225 km/s and with centroids red-shifted to 350 km/s, consistent with the LMC. Superimposed on the emission lines are absorptions by C III and O VI 1031.9 at +260 km/s, which are attributed to warm and hot gas (respectively) in the LMC. The O VI 1037.6 A line is more severely affected by overlying interstellar and H2 absorption from both the LMC and our galaxy. N III 989.8 A is not seen, but models indicate overlying absorption severely attenuates this line. A number of faint lines from hot gas have also been detected, many of which have never been seen in an extragalactic supernova remnant spectrum.
Supernova remnants (SNRs) are widely considered to be sites of Galactic cosmic ray (CR) acceleration. Vela is one of the nearest Galactic composite SNRs to Earth accompanied by the Vela pulsar and its pulsar wind nebula (PWN) Vela X. The Vela SNR is
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We present results from two Chandra/ACIS observations of the so-called Vela ``Bullet D region on the eastern limb of the Vela supernova remnant. The Bullet D region is a bright X-ray feature, identified by Aschenbach et al. (1995) from the ROSAT All-
Sky Survey, which protrudes beyond the blast wave on the eastern side of the remnant. It has been suggested that this feature is a fragment of supernova ejecta which is just now pushing beyond the position of the main blast wave. An alternate explanation is that the feature is a ``break-out of the shock in which inhomogeneities in the ambient medium cause the shock to be non-spherical. The Chandra image shows a fragmented, filamentary morphology within this region. The Chandra spectra show strong emission lines of O, Ne, and Mg. Equilibrium ionization models indicate that the O and Ne abundances are significantly enhanced compared to solar values. However, non-equilibrium ionization models can fit the data with solar O abundances and Ne abundances enhanced by only a factor of two. The Chandra data are more consistent with the shock breakout hypothesis, although they cannot exclude the fragment of ejecta hypothesis.
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