First Results from the Hopkins Ultraviolet Telescope on Astro-2

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Session 30 -- First Results from Astro 2
Oral presentation, Tuesday, June 13, 1995, 2:00pm - 5:30pm

[30.01] First Results from the Hopkins Ultraviolet Telescope on Astro-2

A.F.Davidsen (JHU)

The Hopkins Ultraviolet Telescope was used to carry out more than 20 scientific programs involving spectrophotometry in the 912 to 1850 \AA\ band during the Astro-2 space shuttle mission in March 1995. The instrument's sensitivity was improved by more than a factor 2 compared with its performance on Astro-1, through the use of newly-developed silicon carbide coatings on the mirror and grating. A total of 385 spectra of 265 different objects were obtained at a resolution of 2 to 4 \AA, providing a unique new look at the astrophysically important but little explored wavelength band from Lyman alpha to the Lyman limit. For many interesting problems, the HUT far UV data provide a very useful complement to those that can be obtained at longer UV wavelengths with the Hubble Space Telescope.

I will present some highlights from the mission, including preliminary results of our search for intergalactic helium toward the quasar HS1700+64 at z=2.72. An excellent spectrum of this object was obtained with nearly 20,000~s of exposure, providing information on the He~II Lyman alpha forest and the He~II Gunn-Peterson effect from low density intergalactic gas.

This work is supported by NASA contract NAS 5-27000 to the Johns Hopkins University.

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