scholarly journals Evidence for a galactic component of the diffuse X-ray background

1970 ◽  
Vol 37 ◽  
pp. 280-288
Author(s):  
B. A. Cooke ◽  
R. E. Griffiths ◽  
K. A. Pounds
Keyword(s):  
Energy Range ◽  
Low Energy ◽  
Galactic Latitude ◽  
X Ray ◽  
Latitude Dependence ◽  
The Galaxy ◽  
X Ray Background

It is widely believed that the diffuse X-ray background, observed on several occasions over the energy range from 0.25 keV to above 1 MeV has an extragalactic origin. Evidence for this comes from the generally reported isotropy above several keV [1, 2, 3] and the observed galactic latitude dependence at 0.25 keV, believed to result from the interstellar attenuation of these low energy photons in passage through the Galaxy [4, 5].

scholarly journals Soft X-rays from the Galaxy

1970 ◽  
Vol 37 ◽  
pp. 406-407
Author(s):  
M. J. Rees
Keyword(s):  
Galactic Plane ◽  
Galactic Latitude ◽  
X Rays ◽  
Indirect Methods ◽  
X Ray ◽  
Background Data ◽  
Diffuse Background ◽  
The Galaxy ◽  
X Ray Background ◽  
Significant Flux

Below 1 keV, analyses of X-ray background data are complicated by galactic absorption effects, which cause the received intensity to vary with galactic latitude. Bowyer et al. (1968) observed that the diffuse background did not fall off as rapidly as was expected towards the galactic plane. One plausible interpretation of their data would be to suppose that a significant flux of soft X-rays emanates from the disc itself. I wish to discuss what could be inferred about the latter component from improved observations of its latitude-dependence, and by indirect methods.

scholarly journals ASCA Sky Survey Observations and the Cosmic X-Ray Background in 2-10 KeV

1998 ◽  
Vol 188 ◽  
pp. 197-200
Author(s):  
H. Inoue ◽  
T. Takahashi ◽  
Y. Ueda ◽  
A. Yamashita ◽  
Y. Ishisaki ◽  
...  
Keyword(s):  
Energy Range ◽  
Galactic Plane ◽  
Galactic Latitude ◽  
High Galactic Latitude ◽  
X Ray ◽  
Sky Survey ◽  
X Ray Background ◽  
Excess Component ◽  
Highly Uniform

The X-ray background in the energy range above 2 keV is highly uniform except for an excess component along the Galactic plane. The excess along the plane is considered to be associated with our Galaxy, whereas the rest of the emission is believed to be of extragalactic origin. In this paper, the X-ray background at high Galactic latitude is discussed and is designated as the CXB (cosmic X-ray background) to distinguish it from the Galactic origin.

Comparison of Various Descriptions of X-Ray Tube Spectra

1995 ◽  
Vol 39 ◽  
pp. 127-135 ◽  
Author(s):  
B. Schoßmann ◽  
H. Wiederschwinger ◽  
H. Ebel ◽  
J. Wernisch
Keyword(s):  
Energy Range ◽  
Low Energy ◽  
Characteristic Radiation ◽  
X Ray ◽  
Absorption Correction

We have developed an algorithm for calculating the x-ray tube continuum based on the eqidistribution proposed by Love and Scott, extended the description of white and characteristic radiation given by Wiederschwinger et al for the energy range 10 to 50 keV to the low energy range from 5 to 30 keV, and compared the results from this algorithm to those responses obtained from algorithms using the absorption correction of Pochou and Pichoir, Philibert, Sewell and Pella. The comparison to other models showed a significandy better performance by our model.

Low-energy cosmic X-ray measurements

1969 ◽  
Vol 47 (23) ◽  
pp. 2651-2666 ◽  
Author(s):  
A. J. Baxter ◽  
B. G. Wilson ◽  
D. W. Green
Keyword(s):  
Spectral Analysis ◽  
Energy Range ◽  
Crab Nebula ◽  
Spectral Characteristics ◽  
Low Energy ◽  
Data Recovery ◽  
X Rays ◽  
X Ray ◽  
Recovery System ◽  
The Crab Nebula

An experiment is described to investigate cosmic X rays in the energy range 0.25–12 keV. The data-recovery system and methods of spectral analysis are considered. Results are presented for the energy spectrum of the diffuse X-ray component and its distribution over the northern sky down to 1.6 keV with a limited extension at 0.27 keV.In the energy range 1.6 to 12 keV, the spectrum is represented by:[Formula: see text]although separate analyses indicate a flattening below 4.5 keV to give:[Formula: see text]and[Formula: see text]At the lowest energies, the flux appears to increase more rapidly and exhibits some anisotropy in arrival directions related to the gross galactic structure. Spectral characteristics of the Crab Nebula and Cygnus X-2 have also been determined.

scholarly journals The Fluctuations of the Cosmic X-Ray Background as a Sensitive Tool to the Universal Source Distribution

1981 ◽  
Vol 94 ◽  
pp. 277-278
Author(s):  
P. Giommi ◽  
G. F. Bignami
Keyword(s):  
Low Energy ◽  
Experimental Results ◽  
Space Distribution ◽  
Source Distribution ◽  
X Ray ◽  
Definite Relation ◽  
Sensitive Tool ◽  
X Ray Background ◽  
Flux Curve

Recent experimental results (Giacconi et al, 79, Tananbaum et al 79) ascribe an increasingly important role to the contribution of discrete sources to the low-energy (few Kev) cosmic X-ray background (CXB). While the astrophysical nature of the objects involved is not yet clear, distant and powerful emitters like QSO play probably an important role (e.g. Setti and Woltjer 1979, Field 1980). For them, often the number-flux curve (LogN-LogS) provides useful hints on such properties as space distribution and/or evolution. For the case of the X-ray sources, moreover, a definite relation exists between their LogN-LogS and the granularity of the sky emission as described by the fluctuations of the X-ray background.

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

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.

Description of X-ray Tube Spectra by the Depth Distribution Function of Pochou and Pichoir

1994 ◽  
Vol 38 ◽  
pp. 291-298
Author(s):  
B. Schoβmann ◽  
J. Wernisch ◽  
H. Ebel
Keyword(s):  
Distribution Function ◽  
Energy Range ◽  
Depth Distribution ◽  
Low Energy ◽  
Characteristic Radiation ◽  
Characteristic Peak ◽  
X Ray ◽  
Absorption Correction ◽  
Peak Areas

We have developed an algorithm for calculating the x-ray tube continuum based on the depth distribution function (DDF) proposed by Pochou and Pichoir, extended the description of white and characteristic radiation given by Wiederschwinger et al. to the low energy range from 5 to 30 keV and compared the results frorn these algorithms to the signals obtained from algorithms using the absorption correction of Philibert and of Sewell et al. Preceding calculations the measured spectra were separated into characteristic peak spectra and into the corresponding white spectra, where the background below the peak areas was numerically interpolated.

Characterization of Si(Li) x-ray detector efficiencies in the low energy range

1986 ◽  
Vol 44 ◽  
pp. 710-711
Author(s):  
G. Wirmark ◽  
G. Wahlberg ◽  
H. Nordén
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Energy Range ◽  
Analytical Electron Microscopy ◽  
Low Energy ◽  
Ratio Method ◽  
X Ray ◽  
Standard Specimens ◽  
Analytical Electron

X-ray microanalysis with windowless or ultra-thin window Si(Li)-detectors is becoming increasingly important in analytical electron microscopy. The most common approach in the quantification of this method is the thin film ratio method.where CA and CB denote the concentrations of elements A and B respectively and IA and IB are the corresponding x-ray intensities. The KAB-factor should ideally be determined from analyses of standard specimens of known compositions.

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