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Astron. Astrophys. 357, 387 (2000)

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A calibration of the ROSAT HRI UV leak

T.W. Berghöfer 1,2, J.H.M.M. Schmitt 1 and M. Hünsch 3

1 Universität Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
2 University of California, Space Sciences Laboratory, Berkeley, CA 94720, USA
3 Institut für Theoretische Physik und Astrophysik der Universität Kiel, Olshausenstraße 40, 24118 Kiel, Germany

Astron. Astrophys. 342, L17-L20 (1999)


In the paper "A calibration of the ROSAT HRI UV leak" by Berghöfer, Schmitt & Hünsch (1999, A&A 342, L17) ROSAT HRI UV contamination count rate predictions are reported for the star Betelgeuse. A recent reinvestigation shows that the given numbers are too high, as was also pointed out to us by M. V. Zombeck (private communication). Based on new calculations, including archival IUE low dispersion SWP and LWP spectra and a photospheric model of this star, we compute the following HRI count rate estimates: The logarithmic interpolation of the MCP quantum efficiency between 2500-6000Å provides a count rate of [FORMULA] counts s-1, whereas the exponential interpolation leads to a count rate [FORMULA] counts s-1 in the 2500-6000Å band. The values for the 1000-6000Å band are [FORMULA] counts s-1 (logarithmic MCP interpolation) and [FORMULA] counts s-1 (exponential MCP interpolation).

The new HRI count rate predictions are all consistent with the upper limit derived from the ROSAT HRI observation of Betelgeuse.

Send offprint requests to: T.W. Berghöfer

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© European Southern Observatory (ESO) 2000

Online publication: May 3, 2000