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The nucleus of M 82 at radio and X-ray bands : discovery of a new radio population of supernova candidates.
Kronberg, P. P.; Biermann, P.; Schwab, F. R.
Detailed VLA radio maps are presented of the continuum radio emission in M82 and the X-ray emission from the HRI of the Einstein X-ray satellite. The authors have discovered more than 40 new radio sources within 300 pc of M82's nucleus. It is argued that nearly all of these sources are radio supernovae or supernova remnants and their radio luminos…
EXOSAT observations of a strong soft X-ray excess in MKN 841.
Culhane, J. L.; Fabian, A. C.; Branduardi-Raymont, G. +6 more
EXOSAT observations of the spectrum of the Seyfert 1 galaxy MKN 841 show that it is well-fitted by a power law of photon index 1.6, similar to that of other Seyferts, and a large additional soft component. The X-ray luminosity over the observed band exceeds 4×1044erg s-1. A single-temperature blackbody fit to the soft X-rays …
The galactic ridge observed by Exosat
Warwick, R. S.; Watson, M. G.; Turner, M. J. L. +1 more
We have used Exosat to map the distribution of X-ray emission in the galactic plane. In addition to numerous point sources, the map reveals a narrow continuous ridge of emission which extends along the galactic plane either side of the galactic centre out to ~40° longitude. The origin of this feature remains uncertain although a major contribution…
The old nova GK Per : discovery of the X-ray pulse period.
King, A. R.; Watson, M. G.; Osborne, J.
EXOSAT observations of GK Per during an optical outburst are reported. The hard X-ray emission (greater than 2 keV) shows a strong coherent modulation at a period of 351 s, identifying GK Per as the latest member of the 'intermediate polar' subclass of magnetic cataclysmic variables. The X-ray pulse profile has a quasi-sinusoidal shape with mean a…
The Structure of Low-Mass X-Ray Binaries
White, N. E.; Mason, K. O.
The present knowledge of the structure of low-mass X-ray binary systems is reviewed. We examine the orbital period distribution of these sources and discuss how the orbital periods are measured. There is substantial observational evidence that the accretion disks in low-mass X-ray binaries are thick and structured. In a number of highly inclined s…
The discovery of 4.4 second X-ray pulsations from the rapidly variable X-ray transient V 0332+53.
Stella, L.; Parmar, A. N.; White, N. E. +3 more
Using the EXOSAT Observatory, three outbursts from the transient X-ray source V0332 + 53 have been observed between November 1983 and January 1984. It is found that in addition to the rapid Cyg X-1-like variability previously reported by Tanaka et al. (1983), this source also displays stable pulsations with a period of 4.4 s. Doppler variations in…
EXOSAT observations of broad iron K line emission from Scorpius X-1.
White, N. E.; Taylor, B. G.; Peacock, A.
Using the Exosat Gas Scintillation Proportional Counter a broad iron K emission line is found to be present in the X-ray spectrum of Sco X-1. The line full width half-maximum (FWHM) is 0.7 keV, independent of the source intensity state. During flaring intervals the line intensity remains constant such that the equivalent width, decreases from 50 e…
An X-ray study of AM Herculis. I. Discovery of a new mode of soft X-ray emission.
Stella, L.; Heise, J.; King, A. R. +4 more
The discovery of a new mode of soft X-ray emission of the magnetic cataclysmic variable AM Her is reported. AM Her has been observed in June, August and September 1983 with EXOSAT in both hard (1-30 keV) and soft (40-120 A) X-rays. Hard X-rays were seen to be partially eclipsed and periodic with the white dwarf rotation period. The eclipse phases …
Continuous rapid X-ray variability and spectral changes in NGC 4051.
Elvis, M.; Watson, M. G.; Lawrence, A. +1 more
The observation of rapid X-ray variability in active galaxies is of great potential interest. In Seyfert galaxies, variability on a time-scale of days seems common, but fast (minutes-hours) variability is apparently very rare. In a variability survey with the HEAO-1 A2 experiment, Tennant and Mushotzky (1983) found only one object to vary on short…
The discovery of low-level iron K line emission from CYG X-1.
White, N. E.; Barr, P.; Page, C. G.
The results of seven observations of the X-ray spectrum of Cyg X-1, made using the gas scintillation proportional counter on board the Exosat Observatory are presented. The discovery of a broad emission feature at 6.2 keV is reported with an equivalent width of typically 120 eV. The line is resolved to have an FWHM of about 1.2 keV. There is no ev…