GHRS Instrument Science Report 069

"Stability of the GHRS Side 1 Sensitivity"

Claus Leitherer, Lisa E. Sherbert, Stephen J. Hulbert, and
David R. Soderblom

Abstract excerpted from the report:

The ultraviolet flux standard BD+28D4211 is observed with the GHRS and
grating G140L to monitor the long-term stability of the instrument
sensitivity between 1100A and 1640A. Four observations obtained on
days 94.098, 94.164, 94.213, and 94.294 are available for the
wavelength range 1100A - 1350A. Data for the range 1350A - 1600A
are available for days 94.164, 94.213, and 94.294. The GHRS
sensitivity between 1175A and 1640A is stable within 1.5%. We find
marginal evidence for a sensitivity decrease below 1200A. The decrease
is largest at the shortest wavelength observed (~5% at 1125 A) but has
little statistical significance due to low counts at these
wavelengths.