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[en] We discuss the extent of the hot interstellar phase (approximately 106K) in the direction of the cloud revealed by Strong and Lebrun (1981). The distance (80pc) of the cloud is estimated from measured variation of reddening versus distance in its direction. No X ray absorption by the cloud was observed. This indicates that the hot plasma has an extent less than 80pc, the cloud distance. The value 80pc well agrees with the radius of a SNR supposed to be associated with the hot plasma
[en] Objectives were to conduct observations with the first satellite entirely devoted to x-ray astronomy and to analyze the results obtained. A catalog of x-ray sources was generated, and results of discoveries and further detailed observations of sources were presented in scientific journals and meetings. A list of how objectives were met, a brief description of the instrument, significant results, the x-ray catalog, and a complete bibliography of results are included
[en] This paper present the result of the Einstein observations for the 2CG135+01 region where the result are complete in the sense that we have a satisfactory coverage of the whole COS-B error box and that all the IPC sources found have been identified, through both HRI and optical observations. In particular, the spectral classifications of the present work were obtained at the Lojano Observatory (Bologna, Italy) with the Boller and Chivens spectrograph at the Cassegrain focus of the 1.52 in telescope. The spectral dispersion is 80A/mm
[en] An infrared source at the location of the transient x-ray source A0620-00 was detected and measured on 26.5 and 29.5 August 1975 with the 50-inch reflector at Kitt Peak National Observatory. A preliminary summary of the results is presented here
[en] We present X-ray, infrared, optical, and radio observations of four previously unidentified Galactic plane X-ray sources: AX J163252-4746, AX J184738-0156, AX J144701-5919, and AX J144547-5931. Detection of each source with the Chandra X-ray Observatory has provided sub-arcsecond localizations, which we use to identify bright infrared counterparts to all four objects. Infrared and optical spectroscopy of these counterparts demonstrate that all four X-ray sources are extremely massive stars, with spectral classifications: Ofpe/WN9 (AX J163252-4746), WN7 (AX J184738-0156 = WR121a), WN7-8h (AX J144701-5919), and OIf+ (AX J144547-5931). AX J163252-4746 and AX J184738-0156 are both luminous, hard, X-ray emitters with strong Fe XXV emission lines in their X-ray spectra at ∼6.7 keV. The multi-wavelength properties of AX J163252-4746 and AX J184738-0156 are not consistent with isolated massive stars or accretion onto a compact companion; we conclude that their X-ray emission is most likely generated in a colliding-wind binary (CWB) system. For both AX J144701-5919 and AX J144547-5931, the X-ray emission is an order of magnitude less luminous and with a softer spectrum. These properties are consistent with a CWB interpretation for these two sources also, but other mechanisms for the generation of X-rays cannot be excluded. There are many other as yet unidentified X-ray sources in the Galactic plane, with X-ray properties similar to those seen for AX J163252-4746, AX J184738-0156, AX J144701-5919, and AX J144547-5931. This may indicate a substantial population of X-ray-emitting massive stars and CWBs in the Milky Way.