Reanalyses of Voyager Ultraviolet Spectrometer Limits to the EUV and FUV...
Jerry Edelstein
Diffuse Astronomical Flux
Author(s): Jerry Edelstein, Stuart Bowyer and Michael Lampton
We re-examine {\em Voyager} Ultraviolet Spectrograph data used to establish
upper limits to the $\lambda$ 500-900 \AA and $\lambda$ 900-1100 \AA cosmic
diffuse background. The measurement of diffuse flux with the {\em Voyager} UVS
data requires complex corrections for noise sources which are far larger than
the astronomical signal. In the analyses carried out to date, the upper limits
obtained on the diffuse background show statistical anomalies which indicate
that substantial systematic errors are present. We detail these anomalies and
identify specific problems with the analysis. We derive statistically robust
2~$\sigma$ upper limits for continuum flux of 570~photons~s$^{-1}$
cm$^{-2}$~ster$^{-1}$~\AA$^{-1}$ and for the 1000 \AA~ diffuse line flux of
11,790~photons~s$^{-1}$ cm$^{-2}$~ster$^{-1}$. The true limits may be
substantially higher because of unknown systematic uncertainties. The new
statistical limits alone are insufficient to support previous conclusions based
on the {\em Voyager} data including work on the character of interstellar dust
and estimates of the diffuse extragalactic far UV background as absorbed by
intergalactic dust.
Paper: astro-ph/0003208
Dated: Wed, 15 Mar 2000 01:42:40 GMT (7kb)
Comments: To be published in the Astrophysical Journal
URL: http://arXiv.org/abs/astro-ph/0003208