相关论文: X-rays from wind-blown bubbles: an XMM-Newton dete…

A recent XMM-Newton observation (Zhekov 2014) has revealed diffuse X-ray emission inside the nebula NGC 2359 around the Wolf-Rayet star WR 7. Taking advantage of an improved point-source rejection and background subtraction, and a detailed…

We discuss our most recent findings on the diffuse X-ray emission from Wolf-Rayet (WR) nebulae. The best-quality X-ray observations of these objects are those performed by XMM-Newton and Chandra towards S308, NGC2359, and NGC6888. Even…

We present deep XMM-Newton EPIC observations of the Wolf-Rayet (WR) bubble NGC6888 around the star WR136. The complete X-ray mapping of the nebula confirms the distribution of the hot gas in three maxima spatially associated with the caps…

We report the serendipitous detection of the planetary nebula NGC 5315 by the Chandra X-ray Observatory. The Chandra imaging spectroscopy results indicate that the X-rays from this PN, which harbors a Wolf-Rayet (WR) central star, emanate…

The Wolf-Rayet (WR) nebula NGC3199 has been suggested to be a bow shock around its central star WR18, presumably a runaway star, because optical images of the nebula show a dominating arc of emission south-west of the star. We present the…

We present an analysis of the Suzaku observations of the prototype wind-blown bubble NGC 6888 which is based both on use of standard spectral models and on a direct comparison of theoretical models with observations. The X-ray spectra of…

We have used the excellent sensitivity of XMM-Newton to obtain the first high-quality X-ray spectrum of a Wolf-Rayet (WR) star which is not known to be a member of a binary system. Our target, the nitrogen-type star WR 110 (= HD 165688) was…

We analyze Chandra observations of the Wolf-Rayet (WR) bubble NGC 6888. This WR bubble presents similar spectral and morphological X-ray characteristics to those of S 308, the only other WR bubble also showing X-ray emission. The observed…

We present the results of Chandra X-ray Observatory (CXO) observations of the planetary nebulae (PNs) NGC 40 and Hen 2-99. Both PNs feature late-type Wolf-Rayet central stars that are presently driving fast ~1000 km/s, massive winds into…

XMM-Newton EPIC observations of the planetary nebula (PN) NGC 7009, the Saturn Nebula, have detected extended X-ray emission in its central cavity. The diffuse X-ray emission must originate in the shocked fast stellar wind. The spectra show…

X-ray emitting diffuse nebulae around hot stars are observed to have soft-band temperatures in the narrow range [1-3]$\times10^{6}$ K, independent of the stellar wind parameters and the evolutionary stage of the central star. We discuss the…

The Eskimo Nebula (NGC 2392) is a double-shell planetary nebula (PN) known for the exceptionally large expansion velocity of its inner shell, ~90 km/s, and the existence of a fast bipolar outflow with a line-of-sight expansion velocity…

We present the first high-resolution X-ray spectrum of a putatively single Wolf-Rayet star. 400 ks observations of WR 6 by the XMM-Newton-telescope resulted in a superb quality high-resolution X-ray spectrum. Spectral analysis reveals that…

The central star of NGC 2392 shows the hardest X-ray emission among central stars of planetary nebulae (CSPNe). The recent discovery of a spectroscopic companion with an orbital period of 1.9 days could provide an explanation for its hard…

We report on a new XMM-Newton observation of NGC 247 from December 2009. The galaxy contains a supersoft, ultraluminous X-ray source (ULX) whose spectrum consists of a thermal component with a temperature about 0.1 keV and a power-law tail…

We have obtained Chandra ACIS-S observations of NGC 6543, the Cat's Eye Nebula. The X-ray emission from NGC 6543 is clearly resolved into a point source at the central star and diffuse emission confined within the central elliptical shell…

We present ASCA SIS observations of the wind-blown bubble NGC6888. Owing to the higher sensitivity of the SIS for higher energy photons compared to the ROSAT PSPC, we are able to detect a T ~ 8x10^6 K plasma component in addition to the T ~…

We calculate the X-ray emission from the shocked fast wind blown by the central stars of planetary nebulae (PNs) and compare with observations. Using spherically symmetric self similar solutions, we calculate the flow structure and X-ray…

We present a multiwavelength study of the iconic Bubble Nebula (NGC 7635) and its ionising star BD$+$60$^{\circ}$2522. We obtained XMM-Newton EPIC X-ray observations to search for extended X-ray emission as in other similar wind-blown…

We use radiation-hydrodynamical simulations to investigate the formation and synthetic X-ray emission of hot bubbles within planetary nebulae (PNe) driven by the powerful winds of H-deficient, [Wolf-Rayet]([WR])-type stars. Our models,…