IUE observations of X-ray sources: HD153919 (4U1700–37), HDE226868 (Cyg X-1), HZ Her (Her X-1)

  title={IUE observations of X-ray sources: HD153919 (4U1700–37), HDE226868 (Cyg X-1), HZ Her (Her X-1)},
  author={Andrea K. Dupree and R. J. Davis and Herbert Gursky and Lee Hartmann and John C. Raymond and Albert Boggess and A. Holm and Yoji Kondo and Cc Wu and Ferdinando Duccio Macchetto and Michael C. W. Sandford and Allan J. Willis and R. J. Wilson and Franco Ciatti and J. B. Hatchings and Hugh M. Johnson and Jun Jugaku and Donald C. Morton and Aldo Treves and Edward van den Heuvel},
The first UV spectroscopic measurements of binary X-ray sources with IUE show highly variable emission from a photoionised plasma in the object HZ Her, and give evidence for localised circumsystem material in the binary source Cygnus X-1. In addition, a substantial stellar wind is found in one of the brightest identified X-ray sources HD153919. This system may be surrounded by an extensive H II region unusual in its content of high excitation ion species. 

Hot Outflowing Gas from the X-Ray Binary Hercules X-1

We present a unified picture of outflowing gas from the X-ray binary system Hercules X-1/HZ Herculis. We suggest that the outflowing gas (a wind) causes UV emission seen in mid-eclipse, narrow UV

Detection of an X-ray-ionized nebula around the black hole candidate binary LMC X-l

Optical spectra of the black hole candidate X-ray binary LMC X-l reveal that the system is surrounded by an extended, highly ionized He III region, N159F, which appears to be the long-sought-for

Hopkins Ultraviolet Telescope Observations of Hercules X-1

We have obtained a far-ultraviolet spectrum of the X-ray binary Hercules X-1/HZ Herculis using the Hopkins Ultraviolet Telescope aboard the Astro-1 Space Shuttle mission in 1990 December. This is the

Stellar coronae—Evidence for their existence from X- and UV observations

Stellar coronae were among the first predicted X-ray sources. Because of their relatively low X-ray luminosities, however, they have been discovered only during the last few years.In the present

XMM-Newton X-ray spectroscopy of the high-mass X-ray binary 4U 1700-37 at low flux

A monitoring campaign of the high-mass X-ray binary system 4U 1700−37/HD 153919, carried out with XMM-Newton in February 2001, shows that during the low-flux interval the continuum is strongly reduced, probably due to a reduction of the accretion rate onto the compact object.

Modelling the orbital modulation of ultraviolet resonance lines in high-mass X-ray binaries

The stellar-wind structure in high-mass X-ray binaries (HMXBs) is investigated through modelling of their ultraviolet (UV) resonance lines. For the OB supergiants in two systems, Vela X-1 and 4U1700

Hercules X-1: Empirical Models of Ultraviolet Emission Lines

The UV emission lines of Hercules X-1, resolved with the Hubble Space Telescope (HST) Goddard High Resolution Spectrograph and Space Telescope Imaging Spectrograph, can be divided into broad (FWHM ≈

IUE observations of hot stars: HZ43, BD + 75°325, NGC6826, SS Cygni, η Carinae

During the commissioning phase of IUE observations were made of a selection of hot stars: the white dwarf HZ43, the hot subdwarf BD + 75°325, the nucleus of the planetary nebula NGC6826, the dwarf

IUE observations of absorption by hot gas in the nebula NGC6888

New UV observations of Wolf–Rayet stars obtained with the IUE satellite show narrow absorption components in the highly ionised species of SiIV and CIV. In the case of the WN6 star HD192163 each


Orbital variability has been found in the X-ray hardness of the black hole candidate Cygnus X-1 during the soft/high X-ray state using light curves provided by the Rossi X-ray Timing Explorer's



Compact X-Ray Sources

In Chapter 4, The X-ray Sky, we discussed the general properties of a class of sources designated as ‘compact X-ray sources’, or ‘stellar X-ray sources’, or ‘X-ray stars’. The essential features of

New results from long-term observations of Cygnus X-1.

Observations of Cyg X-1 between 1974 October and 1975 July reveal a persistent 5/subd/./sub /6 modulation of the 3--6 keV X-ray intensity, having a minimum in phase with superior conjunction of the

Evidence for the binary nature of 2U 1700-37.

Analysis of Uhuru data on the X-ray source 2U 1700-37 has revealed the presence of regular occultations. The period is 3.4 days with an occultation duration of 1.1 days. The source is highly variable

Mass transfer in binary X-ray systems

The influence of X-ray heating on gas flows in binary X-ray systems is examined. A simple estimate is obtained for the evaporative wind flux from a stellar atmosphere due to X-ray heating which

Optical clues to the nature of Hercules X-1/HZ Herculis

The 1d/sub ./7 optical light curve of Her X-1/HZ Her varies in a highly systematic fashion over the 35 day X-ray on-off cycle. These variations can be reproduced in some detail by a relatively simple

Further x-ray observations of Hercules X-1 from Uhuru

Recent data are presented concerning the X-ray source Hercules X-1. Details of the 1.24-second pulse shape and its variability are shown. The 1.24- second period is observed to decrease with time,

Soft x-ray sources

Objects that have already been detected as discrete soft x-ray sources are reviewed. They include supernova remnants, a recurrent nova, flare stars, the coronas of nearby stars, SS Cygni, a white

Discovery of a periodic pulsating binary X-ray source in Hercules from Uhuru.

We have discovered a new pulsating X-ray source with a 1.24-sec period in the constellation Hercules. Analysis of 5 months of data has shown the existence of periodic variations in the intensity of

Spectra of Hercules X-1 near a turn-on in the 35 day cycle

X-ray spectra for Her X-l are presented for times before, during, and after a turn-on in the 35 day on-off cycle, as well as during an anomalous dip in the X-ray intensity. All four spectra are well

IUE observations of the interstellar medium

Results from a preliminary study of interstellar absorption lines in the spectra of the three stars HD149757, HD93521 and HD153919, observed by the IUE during its commissioning phase are presented.