----- Submission 1 (Thu Apr 10 11:25:12 GMT 2003) ----- ----- Submission 1 (Thu Mar 27 14:29:05 GMT+01:00 2003) ----- Assigned ID: 1344 Successfully submitted: Thu Mar 27 14:29:30 GMT+01:00 2003 Intergalactic-Ionized Helium toward HS 1700+6416 at maximum QSO brightness We propose to measure the UV energy distribution of HS 1700+6416 (z=2.73) in the range 1200-3000 A. Scientific background is that HS 1700 has been observed recently by FUSE in a long integration (390 ksec). Due to an unexpected brightening of the QSO by a factor of 3 to 4 compared to earlier FUSE and HUT observations the new observations yielded a HeII forest spectrum of spectacular quality. The aim of the proposed HST observation is to measure the UV energy distribution of HS 1700 the knowledge of which is essential for an optimal evaluation of the FUSE HeII spectrum.
We propose to take STIS G 140 L and G 230 L low resolution spectra covering the range 1140-3100 A. A S/N of 10 or more over most of the spectrum requires around 3000 s for each spectral element. If it is not too late we will appreciate a scheduling of these observations for the end of April or beginning of May. During this period a second observation of HS 1700+6416 with FUSE will be conducted. It is a great advantage to get a complete spectrum simultaneously from the far ultraviolet, where the QSO has brightened proved by FUSE, to the optical, where the QSO does not show this variability (own optical observations). QUASAR ABSORPTION LINES AND IGM 12 false false false false SUPPORTED GALAXY QSO J2000 17 01 0.61 +64 12 9.9 J2000 STIS/FUV-MAMA ACCUM Spectroscopic No STIS/FUV-MAMA ACCUM 17 01 0.61 +64 12 9.9 J2000 STIS/NUV-MAMA ACCUM Spectroscopic No STIS/NUV-MAMA ACCUM (Tic-Visit :proposal-id 9982 :visit-id "01" :proposal-version -1 :trans-version "20030408" :date "10-Apr-2003 13:23:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 104848 :tdrss-contact-duration 0 ) (Tic-Obset :proposal-id 9982 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 9982 :visit-id "01" :orbit-number 1 :pcs-time 365 :si-vis-utilization 3046 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3411 :pcs-gap 0 ) false (Tic-Visit :proposal-id 9982 :visit-id "02" :proposal-version -1 :trans-version "20030408" :date "10-Apr-2003 12:35:39.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 104848 :tdrss-contact-duration 0 ) (Tic-Obset :proposal-id 9982 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 9982 :visit-id "02" :orbit-number 1 :pcs-time 365 :si-vis-utilization 3046 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3411 :pcs-gap 0 ) false