X-ray source counts at high galactic latitude from measurements of fluctuations in the X-ray background

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.

Download Full-text

Ariel results on extragalactic X-ray sources

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

10.1098/rspa.1976.0120 ◽

1976 ◽

Vol 350 (1663) ◽

pp. 491-503 ◽

Cited By ~ 12

Keyword(s):

High Latitude ◽

Field Of View ◽

Potential Contribution ◽

Galactic Latitude ◽

Survey Experiment ◽

Spectral Measurements ◽

High Galactic Latitude ◽

X Ray ◽

X Ray Background ◽

The University

Two of the instruments on Ariel 5 are designed to study the weak high galactic latitude X-ray sources, a number of which have been identified with extragalactic objects. The survey experiment of the University of Leicester has detected sources with strengths down to 2-3 Uhuru counts. Several high latitude sources catalogued by Uhuru have apparently dropped in intensity below this level and improved positions have been obtained for other high latitude sources which support the tentative identification with optical counterparts. The pointed instrument from M. S. S. L. has a programme of spectral measurements of identified extragalactic and other weak sources at high galactic latitudes. The field of view of the M. S. S. L. experiment makes the instrument well suited to the study of the diffuse X-ray background. Results are presented from both experiments on a number of the extragalactic sources and, in particular, discussed in relation to their potential contribution to the diffuse X-ray background. Preliminary measurements of the diffuse X-ray background by the M. S. S. L. instruments are presented.

Download Full-text

The X-ray properties of high redshift quasi-stellar objects

Symposium - International Astronomical Union ◽

10.1017/s0074180900152787 ◽

1986 ◽

Vol 119 ◽

pp. 247-252

Author(s):

Scott F. Anderson ◽

Bruce Margon

Keyword(s):

Background Radiation ◽

High Redshift ◽

Galactic Latitude ◽

X Rays ◽

Stellar Objects ◽

High Galactic Latitude ◽

X Ray ◽

Quasi Stellar Objects ◽

X Ray Background ◽

Intermediate Redshift

We describe a program aimed at characterizing the X-ray emission of high redshift QSOs. We have obtained slitless spectra of 50 high galactic latitude fields previously imaged at very high levels of sensitivity by the Einstein Observatory, generally for original goals unrelated to QSOs. Our survey, covering ∼ 17 deg2 of sky to limiting magnitude Bcont ∼ 21, has yielded ∼ 400 previously uncatalogued QSO candidates, each with sensitive new X-ray information available. About 100 of these objects, constituting a “high confidence” set of QSOs, chiefly in the redshift range 1.7 < z < 3 and thus complementary to previous samples with X-ray data, are used to derive the X-ray properties of high redshift QSOs. Even at these most sensitive available X-ray flux levels, only about 25% of the objects are positively detected in X-rays; thus extensive attention has been given to proper treatment of the upper-limit information. We find a mean optical-to-X-ray slope parameter for the sample of . Our results are combined with those of previous surveys to estimate the fraction of the diffuse X-ray background radiation due to QSOs. QSOs are capable of supplying the majority of the radiation, but the chief contribution comes from an annulus of intermediate redshift, moderate luminosity objects.

Download Full-text

Soft X-rays from the Galaxy

Symposium - International Astronomical Union ◽

10.1017/s0074180900004605 ◽

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.

Download Full-text

THE X-RAY TRANSIENT 2XMMi J003833.3+402133: A CANDIDATE MAGNETAR AT HIGH GALACTIC LATITUDE

The Astrophysical Journal ◽

10.1088/0004-637x/757/2/169 ◽

2012 ◽

Vol 757 (2) ◽

pp. 169 ◽

Cited By ~ 2

Author(s):

J. R. Callingham ◽

S. A. Farrell ◽

B. M. Gaensler ◽

G. F. Lewis ◽

M. J. Middleton

Keyword(s):

Galactic Latitude ◽

High Galactic Latitude ◽

X Ray

Download Full-text

Soft X-ray emission from the high galactic latitude X-ray source MX 2140-60

Astrophysics and Space Science ◽

10.1007/bf00648769 ◽

1981 ◽

Vol 77 (1) ◽

pp. 215-220

Author(s):

K. P. Singh ◽

R. K. Manchanda ◽

S. Naranan ◽

B. V. Sreekantan

Keyword(s):

Galactic Latitude ◽

High Galactic Latitude ◽

X Ray

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

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

Symposium - International Astronomical Union ◽

10.1017/s0074180900004411 ◽

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].

Download Full-text