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Article
X-ray Observations of Active Galactic Nuclei in the Cosmological Context
We review recent discoveries of obscured Active Galactic Nuclei at significant redshifts with X-ray observations. Most, if not all, the X-ray luminous galaxies found at faint X-ray fluxes could in fact be obsc...
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Chapter and Conference Paper
Map** cool gas in the ISM with ROSAT
We have investigated the distribution of cool gas within the local interstellar medium (<150 pc) using data derived from both the ROSAT X-ray and EUV all-sky surveys. The EUV/X-ray spectra for a sample of 89 w...
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Chapter and Conference Paper
Small-scale 1/4keV fluctuations due to the local hot bubble
To determine fluctuations in the 1/4 keV emission due to the LHB, without contamination due to sources within the galactic disk, the Galactic halo or the extragalactic background, we have formed a mosaic of PS...
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Chapter and Conference Paper
Features of the Soft X-ray Background and Implications for the EUV Background
A series of eight overlap** ROSAT PSPC observations situated in the Lockman hole region have been analysed in the 0.1 – 0.4 keV band. The total exposure of ∼ 137 ks and the ultra-low interstellar column density...
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Chapter
EUV Astronomy with the Rosat wide Field Camera
The UK Wide Field Camera (WFC) on ROSAT has carried out the first ever all-sky survey for cosmic sources of extreme ultra-violet (EUV) radiation. A first reduction of the survey data has yielded a catalogue of...
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Article
A significant contribution to the cosmic X-ray background from sources associated with nearby galaxies
THE origin of the cosmic X-ray background remains a mystery after thirty years of study. The three properties of the background radiation commonly used for tackling this problem—its spectrum, isotropy and reso...
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Chapter and Conference Paper
The X-ray variability of active galactic nuclei
Recent results relating to the X-ray variability exhibited by active galactic nuclei are reviewed. EXOSAT observations have established, contrary to earlier indications, that X-ray variability on a timescale of a...
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Article
The galactic ridge observed by Exosat
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 galacti...
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Article
EXOSAT observations of the X-ray pulsar 4U1145-619
EXOSAT observations of the X-ray pulsar 4U1145-619 during June and July 1983 and July 1984 confirm that this source shows a regular 187 day outburst cycle in X-rays. The results from pulse timing and X-ray spe...
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Article
A new view of the galactic plane with EXOSAT
A new X-ray image of the galactic plane has been produced using the 45 arcmin square field of view of the Medium Energy Instrument on EXOSAT. This image shows a total of 64 sources including 18 new ones which ...
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Article
The soft X-ray spectrum of NGC 4151
EXOSAT observations of the Seyfert galaxy NGC 4151 over the period July 1983 to April 1984 have revealed a decreasing flux in the 2 –10 keV band. In accord with previous measurements a power law spectrum atten...
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Article
EXOSAT observations of the BL Lac object Mkn 421
The BL Lac object Mkn 421 was observed by EXOSAT four times over a period of six days in February 1984. Significant X-ray variability was apparent on a timescale of less than a day, but with no accompanying sp...
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Chapter and Conference Paper
A New View of the Galactic Plane with Exosat
Anew X-ray image of the galactic plane has been produced using the 45 arcmin square field of view of the Medium Energy Instrument on EXOSAT. This image shows a total of 64 sources including 18 new ones which i...
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Chapter and Conference Paper
EXOSAT Observations of the BL Lac Object MKN 421
The BL Lac object Mkn 421 was observed by EXOSAT four times over a period of six days in February 1984. Significant X-ray variability was apparent on a timescale of less than a day, but with no accompanying sp...
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Chapter and Conference Paper
The Soft X-Ray Spectrum of NGC 4151
EXOSAT observations of the Seyfert galaxy NGC 4151 over the period July 1983 to April 1984 have revealed a decreasing flux in the 2 – 10 keV band. In accord with previous measurements a power law spectrum atte...
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Chapter and Conference Paper
Exosat Observations of the X-Ray Pulsar 4U1145-619
EXOSAT observations of the X-ray pulsar 4U1145-619 during June and July 1983 and July 1984 confirm that this source shows a regular 187 day outburst cycle in X-rays. The results from pulse timing and X-ray spe...
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Article
Periodic X-ray outbursts from A0535+26, 2S1145-619 and GX301-2
We report Ariel V(SSI) observations of three X-ray pulsars A0535+26, 2S1145-619 and GX301-2 (2S1223-624). These sources exhibit X-ray outbursts which appear, on the basis of observations extending over ∼ 5 yea...
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Article
Ultraviolet, optical and X-ray monitoring of the continuum of NGC 4151
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Chapter and Conference Paper
Periodic X-Ray Outbursts from A0535+26, 2S1145-619 and GX301-2
We report Ariel V(SSI) observations of three X-ray pulsars A0535+26, 2S1145-619 and GX301-2 (2S1223-624). These sources exhibit X-ray outbursts which appear, on the basis of observations extending over ∿ 5 yea...
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Chapter and Conference Paper
Ultraviolet, Optical and X-Ray Monitoring of the Continuum of NGC 4151
The nucleus of the Seyfert galaxy NGC 4151 has been extensively monitored with the International Ultraviolet Explorer (IUE) in the wave- length range 1200–3000 Å, a region of the spectrum where the contaminati...
