Impulsive X-ray Emission by the Sun

Solar X-ray bursts have been observed by a xenon-methane filled proportional counter on the satellite IMP-F. The counter is one inch deep and has a 14 mg/cm2 beryllium window. A slat collimator restricts the field of view to a full width of 5° in the direction of the satellite spin while allowing the counter to see ±60° in the plane containing the spin axis. The effective window area of the counter is 2.2 cm2, after allowing for the collimator.

Download Full-text

A Rocket-Borne X-Ray Spectrometer/Monochromator System for Mapping the Solar Corona

Symposium - International Astronomical Union ◽

10.1017/s007418090010347x ◽

1971 ◽

Vol 41 ◽

pp. 181-181

Author(s):

L. W. Acton ◽

R. C. Catura ◽

J. L. Culhane ◽

A. J. Meyerott

Keyword(s):

Spatial Distribution ◽

Solar Corona ◽

Proportional Counter ◽

Line Emission ◽

Field Of View ◽

The Sun ◽

X Ray ◽

Rocket Flight

A rocket payload is being prepared for the purpose of examining the spatial distribution of line emission from two important ions, Ovii and Neix, in the solar corona. The payload will contain the following integrated set of instruments.(1) A pair of X-ray spectrometers utilizing KAP crystals of approximately 100 cm2 area.(2) An optical aspect camera with a 1 Å bandpass H-α filter to measure the location of the field of view of the X-ray systems on the sun through out the rocket flight.(3) A collimated proportional counter spectrometer operating in the 3 to 15 keV range.

Download Full-text

Galactic Background Radiation in the 78 to 111 EV Band

Symposium - International Astronomical Union ◽

10.1017/s0074180900240801 ◽

1990 ◽

Vol 139 ◽

pp. 241-242

Author(s):

W. T. Sanders ◽

J. J. Bloch ◽

B. C. Edwards ◽

K. Jahoda ◽

M. Juda ◽

...

Keyword(s):

Proportional Counter ◽

Count Rate ◽

Background Radiation ◽

Field Of View ◽

Sounding Rocket ◽

Full Width ◽

Half Maximum ◽

Maximum Field ◽

Galactic Background

Galactic background radiation has been observed in the 78-111 eV Be band using 5000 Å beryllium filters in front of a thin-window proportional counter collimated to a 15° full width at half maximum field of view. Be band data have been analyzed from two sounding rocket flights (Bloch et al. 1986, Juda 1988) that viewed seventeen different directions distributed over the northern galactic hemisphere. In Figure 1 the pointing directions of the two flights are indicated on a map from McCammon et al. (1983) of the 130-188 eV B band count rate.

Download Full-text

A scanning X-ray spectroheliograph

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1970.0105 ◽

1970 ◽

Vol 317 (1528) ◽

pp. 101-112 ◽

Cited By ~ 2

Keyword(s):

Proportional Counter ◽

Grazing Incidence ◽

The Sun ◽

Design And Development ◽

X Ray ◽

Preliminary Results

A grazing incidence reflector which focuses radiation on to a proportional counter has been used to obtain X -ray pictures of the Sun in a number of relatively narrow wavelength bands below 2 nm. The design and development of the instrument is discussed together with the preliminary results from two rocket flights.

Download Full-text

A Search for the Signature of the Diffuse Soft X-ray Background in the ROSAT Wide-Field Camera All-Sky Survey

International Astronomical Union Colloquium ◽

10.1017/s0252921100036113 ◽

1996 ◽

Vol 152 ◽

pp. 289-293

Author(s):

R.G. West ◽

R. Willingale ◽

J.P. Pye ◽

T.J. Sumner

Keyword(s):

Charged Particles ◽

Field Of View ◽

Wide Field ◽

Galactic Latitude ◽

The Sun ◽

X Ray ◽

Cosmic Background ◽

Sky Survey ◽

Cosmic Abundance ◽

X Ray Background

We present the results of an attempt to locate the signature of the diffuse soft X-ray background in the ROSAT Wide-Field Camera (WFC) all-sky survey. After removal of non-cosmic background sources (eg. energetic charged particles), the field-of-view integrated count rate in the WFC S1a filter (90–185 eV) shows no consistent variation with Galactic latitude or longitude. We place limits on the signal from the soft X-ray background (SXRB) in the WFC, and show that these limits conflict with the observations of the Wisconsin Sky Survey if the SXRB in this energy range is assumed to be produced by a thermal plasma of cosmic abundance and a temperature T ~ 106 K within d ~ 100 pc of the Sun.

Download Full-text

X-Ray Observations of M87’s Halo

Highlights of Astronomy ◽

10.1017/s1539299600004603 ◽

1980 ◽

Vol 5 ◽

pp. 689-693

Author(s):

D. Fabricant ◽

M. Lecar ◽

P. Gorenstein

Keyword(s):

Proportional Counter ◽

Total Mass ◽

Precise Determination ◽

Virgo Cluster ◽

Field Of View ◽

Two Dimensional ◽

X Ray ◽

Einstein Observatory ◽

Extended Emission

We briefly describe the soft X-ray image of M87 obtained using the imaging proportional counter aboard the Einstein Observatory. These data provide further strong evidence for the existence of a massive halo of dark matter surrounding M87 and allow a much more precise determination of its mass. Two pointing positions of the satellite were analyzed; one centered on M87, the other 63’ south and 25’ east of M87. The field of view of the imaging proportional counter is 60’ × 60’, and it attains a two dimensional spatial resolution of ˜ 1.5’ in a spectral range spanning 0.1 to 4.5 keV.As previous reports had suggested (Gorenstein et al. 1977; Fabricant et al. 1978), the present observations show M87 to be a strong, very extended, thermal X-ray source with a temperature near 2 keV, surrounded by weaker and still more extended emission from hotter gas associated with the Virgo cluster as a whole (Davison, 1978; Lawrence, 1978). We find M87 to have a total 0.5-4.5 keV X-ray luminosity of about 2 × 1043 ergs/sec, and an extrapolated 2-6 keV luminosity of approximately 1 × 1043 ergs/sec. The total mass of gas inferred from the X-ray measurement exceeds 1012 solar masses.

Download Full-text

Review of Recent Observations of Cluster X-Ray Sources Using the Einstein Observatory

Highlights of Astronomy ◽

10.1017/s1539299600004652 ◽

1980 ◽

Vol 5 ◽

pp. 727-734

Author(s):

Stephen S. Murray

Keyword(s):

Energy Resolution ◽

Proportional Counter ◽

Field Of View ◽

Clusters Of Galaxies ◽

X Ray ◽

Moderate Energy ◽

Einstein Observatory

In this contribution I shall review briefly some of the recent research being carried out at the Harvard-Smithsonian Center for Astrophysics in the study of X-ray emission from clusters of galaxies. This work is being done by several of us at CFA, and I particularly wish to thank Drs. Christine Jones, William Forman, and J. Patrick Henry for permission to discuss their results. The data have been obtained from the Einstein X-ray Observatory (HEAO-2) using the imaging instruments, and in particular the Imaging Proportional Counter (IPC). This gives X-ray images with about l½ arc minute resolution over a field of view of ½° × ½° and moderate energy resolution over a band from 0.5 to 3.0 keV. (For further details see Giacconi et al. 1979).

Download Full-text

Recent Results on Extragalactic Cosmic X-Ray Sources from Rocket and Balloon Flights

Highlights of Astronomy ◽

10.1017/s1539299600001118 ◽

1968 ◽

Vol 1 ◽

pp. 184-187

Author(s):

G. W. Clark

Keyword(s):

Radio Galaxy ◽

Effective Area ◽

Field Of View ◽

X Ray ◽

Beryllium Window ◽

Proportional Counters

Two experiments carried out recently at M.I.T. gave results which bear on the problems of extragalactic X-ray sources. One of these is the work of a group under the direction of Hale Bradt (Bradt et al., 1967), who used an attitude-controlled Aerobee rocket to scan a portion of the sky which included the radio galaxy M 87 (Virgo A). Among their detectors were two banks of argon-filled, 2 mil beryllium window proportional counters, each with an effective area of 350 cm2 and a mechanical collimator giving a 2° × 20° FWHM field of view. The fields of view were crossed so that their long directions made an angle of 60° with one another. Aspect was determined to within 5 min of arc by star photography.

Download Full-text

Recent High Resolution X-Ray Spectra of the Sun

International Astronomical Union Colloquium ◽

10.1017/s0252921100089922 ◽

1972 ◽

Vol 14 ◽

pp. 740-741

Author(s):

J. H. Parkinson ◽

K. Evans ◽

K. A. Pounds

Keyword(s):

High Resolution ◽

Active Region ◽

Wavelength Range ◽

South Australia ◽

Active Regions ◽

Effective Area ◽

Field Of View ◽

The Sun ◽

X Ray

New results are presented from high resolution Bragg crystal spectrometers flown in late 1970 on two Skylark rockets. The first instrument, launched on 24 November 1970 at 22 13 UT from Woomera, South Australia, contained two crystal spectrometers, each with an effective area of 50 cm2 and field collimation to 3’ FWHM. This instrument obtained the X-ray spectrum of the quiet corona in the wavelength range 5–14 Å. The second instrument was launched on 6 December 1970 at 11 13 UT from Sardinia, Italy, and contained four crystals of 6 cm2, each collimated to 4’ FWHM. This instrument was pointed at a non-flaring active region near N20 W40(McMath region 11060), and obtained an X-ray spectrum between 5 and 23 Å. This first use of a collimator to limit the field of view has considerably increased the spectral clarity compared with earlier observations by excluding the contributions of other active regions.

Download Full-text

Crystal spectrometry of active regions on the Sun

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1973.0089 ◽

1973 ◽

Vol 334 (1597) ◽

pp. 231-239 ◽

Cited By ~ 5

Keyword(s):

Line Emission ◽

Active Regions ◽

Field Of View ◽

Sounding Rocket ◽

The Sun ◽

Crystal Spectrometer ◽

Isothermal Model ◽

X Ray ◽

Solar Observations ◽

History Of

A crystal spectrometer has been flown on a sounding rocket to study the soft X-ray line emission from the sun. Collimators, with a field of view 9 arc min square, allowed individual active regions to be observed. A detailed description of the instrument is given. Solar conditions at the time of launch are then discussed, together with a brief history of the three active regions studied. It is shown that the collimators performed satisfactorily. The spectrum of an active region is used to identify the important solar line emission, and a comparison of the spectra obtained near 1.7 nm is made. The temperatures of the regions are discussed, and it is shown that a non-isothermal model is required. A good correlation is found between the soft X-ray emission and other solar observations.

Download Full-text