Publication Date:
2011-08-24
Description:
A revised limit on the local X-ray emissivity due to sources correlated with nearby galaxies is obtained. These results are extrapolated up to a redshift of about 5, and it is found that a smaller, but still significant, fraction of the X-ray background (30 +/- 15 percent) can be accounted for by these sources. Evolution of the source properties and/or a new population of sources at high redshift is required to explain the residual background emissions.
Keywords:
SPACE RADIATION
Type:
Nature (ISSN 0028-0836); 364; 6439; p. 693-695.
Format:
text
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