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[en] The genetic relationship between supernovae (SNe) and supernova remnants (SNRs) is an important factor in understanding the nature of both phenomena. We present here some new results on SNe and SNRs and discuss their implications in the SN-SNR relationship
[en] A discussion of reasons to expect luminous stars in the vicinity of supernova remnants is followed by a list of them from the Luminous Stars in the Northern- and Southern-Milky Way catalogs inside the areas of 24 SNR in An Optical Atlas of Galactic Supernova Remnants and in distances that are consistent with the SNR distances. This is supplemented by remarks on stars and other data of seven more optical counterparts of possible SNR that are not in the Atlas, including new spectroscopic data of S 104 and S 188. (31 references, 3 tables) (U.S.)
[en] We present a measurement of the expansion and brightening of G1.9 + 0.3, the youngest Galactic supernova remnant (SNR), comparing Chandra X-ray images obtained in 2007 and 2009. A simple uniform-expansion model describes the data well, giving an expansion rate of 0.642% ± 0.049% yr-1 and a flux increase of 1.7% ± 1.0% yr-1. Without deceleration, the remnant age would then be 156 ± 11 yr, consistent with earlier results. Since deceleration must have occurred, this age is an upper limit; we estimate an age of about 110 yr or an explosion date of about 1900. The flux increase is comparable to reported increases at radio wavelengths. G1.9+0.3 is the only Galactic SNR increasing in flux, with implications for the physics of electron acceleration in shock waves.
[en] The possibility that a Rayleigh-Taylor instability may lead to an early fragmentation of a supernova shell is investigated by means of 1-, 2-, and 3-dimensional hydrodynamic simulations. In particular, we consider a point explosion in a n = 3 polytrope, but in contrast to recent simulations with smoothed particle hydrodynamics, we do not find evidence for fragmentation of the shell. These results are in accord with analytic considerations
[en] We have carried out CO J = 2 - 1 and CO J = 3 - 2 observations toward Tycho's supernova remnant (SNR) using the KOSMA 3m-telescope. From these observations, we identified three molecular clouds (MCs) around the SNR. The small cloud in the southwest was discovered for the first time. In the north and east, two MCs (Cloud A and Cloud B) adjacent in space display a bow-shaped morphology, and have broad emission lines, which provide some direct evidences of the SNR-MCs interaction. The MCs are revealed at -69∼ -59 km s-1, coincident with Tycho's SNR. The MCs associated with Tycho's SNR have a mass of ∼ 2.13 x 103 Mcircleddot. Position-velocity diagrams show the two clouds to be adjacent in velocity, which means cloud-cloud collision could occur in this region. The maximum value (0.66 ± 0.10) of the integrated CO line intensity ratio (ICOJ=3-2/ICOJ=2-1) for the three MCs agrees well with the previous measurement of individual Galactic MCs, implying that the SNR shock drove into the MCs. The two MCs have a line intensity ratio gradient. The distribution of the ratio appears to indicate that the shock propagates from the southwest to the northeast.
[en] A Catalogue of Supernovae (SNe) is presented which tabulates the main data relative to all extragalactic SNe discovered up to 1988 December 31, and to their parent galaxies. In total 661 SNe are listed of which 267 are classified. For an easier consultation, two lists are given where the SNe are ordered chronologically and by Right Ascension, respectively. The overall distribution of classified supernovae over the morphological types of their parent galaxies is also presented in a summary table
[en] The radio source Sgr A has been mapped with the Very Large Array (VLA) at 6 and 20 cm with an angular resolution of 5'' x 8'' arc. In agreement with the earlier 'WORST' map, the non-thermal source Sgr A East shows a shell structure, while the thermal source Sgr A West shows a spiral-like morphology. The authors suggest that Sgr A East is a supernova remnant (SNR) near the galactic centre. Its surface brightness is the third largest in our galaxy after Cas A and the Crab Nebula. The diameter is 9 pc and the source fits the surface-brightness diameter relationship of Clark and Caswell (1976) if a distance of 10 kpc is assumed. (Auth.)