The Supernova Remnant CTA 1

The supernova remnants G327.1-1.1 and G327.4+0.4 (Kes 27) are located 1.5 deg apart in the constellation Norma. In 1980, Einstein IPC observations discovered that both were irregular filled-center X-ray sources with possible point sources superposed. This paper describes new ROSAT position sensitive proportional counter (PSPC) observations which both map the diffuse structure and clearly show several unresolved sources in each field. Both remnants have bright emitting regions inside the limb which might indicate the presence of high energy electrons accelerated by a pulsar. The interior region is more prominent in G327.1-1.1 than in Kes 27. The spectra are relatively strongly absorbed, as expected from distant remnants close to the galactic plane. Comparison of the X-ray and radio maps of each remnant allows us to attribute some emission to a shell and some to the interior. With this information, a blast-wave model is used to derive approximate ages and energy release. Indications are that the Kes 27 supernova deposited approximately 10(exp 51) ergs in the surrounding medium. The G327.1-1.1 event probably deposited a factor of 3-10 less

The Thermal Composite Supernova Remnant Kes 27 as Viewed by CHANDRA: Shock Reflection from a Cavity Wall

We present a spatially resolved spectroscopic study of the thermal composite supernova remnant Kes 27 with Chandra. The X-ray spectrum of Kes 27 is characterized by K lines from Mg, Si, S, Ar, and Ca. The X-ray emitting gas is found to be enriched in sulphur and calcium. The broadband and tri-color images show two incomplete shell-like features in the northeastern half and brightness fading with increasing radius in the southwest. There are over 30 unresolved sources within the remnant. None show characteristics typical of young neutron stars. The maximum diffuse X-ray intensity coincides with a radio bright region along the eastern border. In general, gas in the inner region is at higher temperature and emission is brighter than from the outer region. The gas in the remnant appears to approach ionization equilibrium. The overall morphology can be explained by the evolution of the remnant in an ambient medium with a density enhancement from west to east. We suggest that the remnant was born in a pre-existing cavity and that the inner bright emission is due to the reflection of the initial shock from the dense cavity wall. This scenario may provide a new candidate mechanism for the X-ray morphology of other thermal composite supernova remnants.Comment: 11 emulateapj pages (including 10 figures), a few references adde

Investigation relative to the Roentgen Satellite (ROSAT)

Reports include: High Resolution Observations of the Central Region of M31; The X-ray Emission of Low-X-ray-Luminosity Early-Type Galaxies: Gas Versus Compact Sources; Interaction Between Cluster Gas and Radio Features of Cygnus A; Hot Gas and Dark Halos in Early-Type Galaxies; A Gravitational Lens in X-rays - 0957+461; How Massive are Early-Type Galaxies?; Three Crab-Like SNR in the Large Magellanic Cloud; and Soft X-ray Emission from Boundary Layers in Cataclysmic Variables. Papers submitted to the Astrophysical Journal are attached

Exploring the X-ray Universe

Capturing the excitement of X-ray astronomy, this second edition textbook for undergraduate students now covers a broader range of topic