Positive Detection of an Excess of Low-Energy Diffuse X-Rays at High Galactic Latitude

1972 ◽  
Vol 177 ◽  
pp. 375 ◽  
Author(s):  
D. J. Yentis ◽  
R. Novick ◽  
P. vanden Bout
Keyword(s):  
Low Energy ◽  
Galactic Latitude ◽  
X Rays ◽  
High Galactic Latitude

A fast transient source of hard X-rays at high galactic latitude

1976 ◽  
Vol 206 ◽  
pp. L139 ◽  
Author(s):  
S. Rappaport ◽  
J. Buff ◽  
G. Clark ◽  
W. H. G. Lewin ◽  
T. Matilsky ◽  
...  
Keyword(s):  
Galactic Latitude ◽  
X Rays ◽  
High Galactic Latitude ◽  
Transient Source ◽  
Fast Transient

Galactic-Latitude Dependence of Low-Energy Diffuse X-Rays

1972 ◽  
Vol 177 ◽  
pp. 365 ◽  
Author(s):  
D. J. Yentis ◽  
R. Novick ◽  
P. vanden Bout
Keyword(s):  
Low Energy ◽  
Galactic Latitude ◽  
X Rays ◽  
Latitude Dependence

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

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.

scholarly journals SAO 244567 (HEN1357): A Post-Agb Star which has turned into a Planetary Nebula within the last 20 years

1998 ◽  
Vol 11 (1) ◽  
pp. 358-358
Author(s):  
M. Parthasarathy
Keyword(s):  
Planetary Nebula ◽  
Far Infrared ◽  
Central Star ◽  
Terminal Velocity ◽  
Galactic Latitude ◽  
Iras Source ◽  
High Galactic Latitude ◽  
Alpha Emission ◽  
Early Type Star ◽  
Emission Strength

SAO 244567 (Henl357) (IRAS 17119-5926) is a high galactic latitude (1 = 331°, b = −12°) early type star, originally classified as a B or A type H-alpha emission line star by Henize (1976). It is an IRAS source with far infrared colours similar to planetary nebulae. The IUE ultraviolet spectra obtained during the last eight years show that the central star is rapidly evolving. It is found that the central star of this young PN has faded by a factor of 3 within the last seven eight years. The terminal velocity of the stellar wind has decreased from −3500 km/sec in 1988 to almost zero in 1994. In 1988 the C IV (1550A) line which was a P-Cygni profile with strong absorption component had almost vanished by 1994. The CIII] 1909A emission strength increased markedly within 4 years from 1988 to 1992. The optical spectra obtained since 1990 shows very clearly only the nebular spectrum which is very similar to that of low excitation planetary nebula. The optical spectrum of SAO 244567 obtained in 1971 shows that it was a post-AGB B 1 or B2 supergiant at that time. This result shows that SAO 244567 has turned into a planetary nebula within the last 20 years. Recently Bobrowsky (1994) obtained narrowband optically resolved images in both H-beta and [OIII] 5007A with the HST planetary camera which revealed a well resolved nebula of size 2 seconds of arc. In this paper we discuss the recent new results.

scholarly journals Unexpected circular radio objects at high Galactic latitude

2021 ◽  
Vol 38 ◽  
Author(s):  
Ray P. Norris ◽  
Huib T. Intema ◽  
Anna D. Kapińska ◽  
Bärbel S. Koribalski ◽  
Emil Lenc ◽  
...  
Keyword(s):  
Galactic Latitude ◽  
High Galactic Latitude ◽  
Square Kilometre Array ◽  
Pilot Survey ◽  
The Universe

Abstract We have found a class of circular radio objects in the Evolutionary Map of the Universe Pilot Survey, using the Australian Square Kilometre Array Pathfinder telescope. The objects appear in radio images as circular edge-brightened discs, about one arcmin diameter, that are unlike other objects previously reported in the literature. We explore several possible mechanisms that might cause these objects, but none seems to be a compelling explanation.

Key comparison BIPM.RI(I)-K2 of the air-kerma standards of the LNE–LNHB, France and the BIPM in low-energy x-rays

Metrologia ◽  
2011 ◽  
Vol 48 (1A) ◽  
pp. 06013-06013 ◽  
Author(s):  
D T Burns ◽  
P Roger ◽  
M Denozière ◽  
E Leroy
Keyword(s):  
Low Energy ◽  
X Rays ◽  
Key Comparison ◽  
Air Kerma
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