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21. |
Effects of nuclear collisions in extragalactic radio sources |
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AIP Conference Proceedings,
Volume 245,
Issue 1,
1992,
Page 250-252
P. N. Okeke,
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PDF (116KB)
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摘要:
We review briefly the consequences of proton‐proton (pp) collisions in extragalactic radio jets—a problem which we have been tackling since 1982. Effort was made to answer the following questions: Can the results of pp collisions in the jets account for the observed radio, optical and gamma ray emission from the jets of extragalactic radio sources (EGRS)? What is the nature of these relativistic protons? What is the origin of the central gaps which are observed in EGRS?
ISSN:0094-243X
DOI:10.1063/1.41714
出版商:AIP
年代:1992
数据来源: AIP
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22. |
The International Ultraviolet Explorer project (IUE) |
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AIP Conference Proceedings,
Volume 245,
Issue 1,
1992,
Page 253-265
Willem Wamsteker,
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PDF (704KB)
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摘要:
A summary of the definition and evolution of the International Ultraviolet Explorer Satellite (IUE) is given. Some examples highlighting the exceptional success of the Project are presented. The specific nature of the IUE Porject which has made this success possible are equally applicable to the stimulation of the participation of scientists from the developing countries in the IUE project. This will stimulate the development of the capabilities needed, to make a larger participation of the developing countries in the Basic Space Sciences a reality.
ISSN:0094-243X
DOI:10.1063/1.41715
出版商:AIP
年代:1992
数据来源: AIP
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23. |
Early results from the Cosmic Background Explorer (COBE) |
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AIP Conference Proceedings,
Volume 245,
Issue 1,
1992,
Page 266-278
J. C. Mather,
M. G. Hauser,
C. L. Bennett,
N. W. Boggess,
E. S. Cheng,
R. E. Eplee,
H. T. Freudenreich,
R. B. Isaacman,
T. Kelsall,
C. M. Lisse,
S. H. Moseley,
R. A. Shafer,
R. F. Silverberg,
W. J. Spiesman,
G. N. Toller,
J. L. Weiland,
S. Gulkis,
M. Jansssen,
P. M. Lubin,
S. S. Meyer,
R. Weiss,
T. L. Murdock,
G. F. Smoot,
D. T. Wilkinson,
E. L. Wright,
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PDF (770KB)
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摘要:
The Cosmic Background Explorer, launched November 18, 1989, has nearly completed its first full mapping of the sky with all three of its instruments: a Far Infrared Absolute Spectrophotometer (FIRAS) covering 0.1 to 10 mm, a set of Differential Microwave Radiometers (DMR) operating at 3.3, 5.7, and 9.6 mm, and a Diffuse Infrared Background Experiment (DIRBE) spanning 1 to 300 &mgr;m in ten bands. A preliminary map of the sky derived from DIRBE data is presented. Initial cosmological implications include: a limit on the Comptonizationyparameter of 10−3, on the chemical potential &mgr; parameter of 10−2, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy has the spectrum expected from a Doppler shift of a blackbody. There are no significant anisotropies in the microwave sky detected, other than from our own galaxy and a cos &thgr; dipole anisotropy whose amplitude and direction agree with previous data. At shorter wavelengths, the sky spectrum and anisotropies are dominated by emission from ‘local’ sources of emission within our Galaxy and Solar System. Preliminary comparison ofIRASandDIRBEsky brightnesses toward the ecliptic poles shows theIRASvalues to be significantly higher than found byDIRBEat 100 &mgr;m. We suggest the presence of gain and zero‐point errors in theIRAStotal brightness data. The spacecraft, instrument designs, and data reduction methods are described.
ISSN:0094-243X
DOI:10.1063/1.41716
出版商:AIP
年代:1992
数据来源: AIP
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24. |
Search for life beyond Earth |
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AIP Conference Proceedings,
Volume 245,
Issue 1,
1992,
Page 279-292
Raj K. Khanna,
Cyril Ponnamperuma,
Rafael Navarro‐Gonza´lez,
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PDF (550KB)
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摘要:
A brief account of our understanding of prebiotic conditions which may have existed for the origin of life on Earth are presented. The production of key molecules, HCN and HCHO, from less reducing atmospheric conditions is not extremely efficient. Their incorporation into the Earth from cometary impacts needs to be given serious consideration.
ISSN:0094-243X
DOI:10.1063/1.41717
出版商:AIP
年代:1992
数据来源: AIP
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