----- Attempting Submission 2 (Mon Sep 22 20:48:44 GMT 2008) ----- Phase II Proposal 11642 (lmcx3-Sep-18.apt) successfully submitted. ----- Attempting Submission 3 (Mon Sep 22 20:49:25 GMT 2008) ----- FUV/X-ray absorption and emission line spectroscopy of the Galactic corona The Galactic corona is believed to play an essential role in the ``ecosystem'' of the Galaxy. But the extent and ionization state as well as the physical properties of the corona are yet to be determined. We request COS/HST observations to sample the intervening gas through the line absorptions of CIV, NV, SiIV, OI, SII, SiII, and FeII along the LMC X-3 sight line, toward which we have already detected OVI, OVII, and NeIX absorption lines and NVII, OVII, OVIII, and NeIX emission lines with FUSE, Chandra, and Suzaku observations. We have developed a software tool to jointly analyze the far-UV/X-ray absorption and emission spectra. The requested observations will not only allow us to rigorously test our preliminary results based on the existing observations, but also enable us to examine various models (e.g., diffuse hot gas vs. conductive layers) and to constrain the spatial and thermal properties of the hot gas over a broad temperature range. The results will p! rovide a unique calibration of our understanding of the corona.
The main goals of this project are to test our preliminary results based on a multiwavelength campaign and to investigate the spatial and thermal properties of the Galactic hot gas. To this end, we seek to obtain high resolution spectra of LMC X-3 covering the high ionization as well as the low ionization species. Our previous studies predict column densities of C IV and N V to be 6E13 and 2.2E13 cm^-2, respectively, contained in the hot diffuse gas toward the LMC X-3 sight line. Detecting these lines is our fundamental requirement and also drives the requested S/N level. LMC X-3 is mildly variable in UV wavelength band. We therefore use a spectrum with a typical flux obtained from one of the previous IUE observations as the input to the Exposure Time Calculator to estimate the ACQ-target-searching and ACQ-target-imaging time and to calculate the Buffer-time. The approved 7 orbits are split into two visits, in which the first 6 orbits use the COS/G130 grating to detect the N V absorption line while the seventh orbit uses the COS/G160 to detect the C IV line. With this exposure allocation, we expect to obtain a spectrum with S/N of 35 and 11 around N V and C IV wavelengths, respectively, which allows us to to detect these lines at >5sigma significant levels (with the expected column densities). To reduce COS fixed-pattern noise but also to minimize the overhead times associated with the OSM movement at the same time, we use a grating at different central wevelengths in successive exposures to mimic the different FP-POS offsets. By doing this, we will also obtain a spectrum coving the entire wavelength range; the gaps at different wavelengths are also filled up with nearly even exposures. ISM AND CIRCUMSTELLAR MATTER 12 false 0.0 0.0 false false false false false SUPPORTED EXT-STAR B3-B5 V-IV MXB This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 05 38 56.2100 -64 04 56.10 J2000 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G160M 1577 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. /Users/yaoys/proposal/HST17/LMCX3/OP-cache/lmcx3-Sep-18-v01.xml Find a UV source from the Galex survey, which may confuse the proposed target. So a visit orientation constraint is requested to exclude that source from the BOA. (Tic-Visit :proposal-id 11642 :visit-id "01" :proposal-version -1 :trans-version "20080609" :date "18-Sep-2008 13:48:54.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 417632 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11642 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11642 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3198 :al-overhead-at-end 0 :internal-dur-at-end 116 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3531 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11642 :visit-id "01" :orbit-number 2 :pcs-time 195 :si-vis-utilization 3336 :al-overhead-at-end 0 :internal-dur-at-end 50 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3531 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11642 :visit-id "01" :orbit-number 3 :pcs-time 195 :si-vis-utilization 3336 :al-overhead-at-end 0 :internal-dur-at-end 69 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3531 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11642 :visit-id "01" :orbit-number 4 :pcs-time 195 :si-vis-utilization 3336 :al-overhead-at-end 0 :internal-dur-at-end 381 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3531 :pcs-gap 0 ) true 4 0 COS84126 COS84127 COS84129 COS84130 COS84130 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. /Users/yaoys/proposal/HST17/LMCX3/OP-cache/lmcx3-Sep-18-v02.xml Find a UV source from the Galex survey, which may confuse the proposed target. So a visit orientation constraint is requested to exclude that source from the BOA. (Tic-Visit :proposal-id 11642 :visit-id "02" :proposal-version -1 :trans-version "20080609" :date "18-Sep-2008 14:06:52.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 713360 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11642 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11642 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3198 :al-overhead-at-end 0 :internal-dur-at-end 116 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3531 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11642 :visit-id "02" :orbit-number 2 :pcs-time 195 :si-vis-utilization 3336 :al-overhead-at-end 0 :internal-dur-at-end 116 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3531 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11642 :visit-id "02" :orbit-number 3 :pcs-time 195 :si-vis-utilization 3336 :al-overhead-at-end 0 :internal-dur-at-end 362 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3531 :pcs-gap 0 ) true 3 0 COS84126 COS84126 COS84133 COS84133 COS84135 COS84135 COS84136; using exposure time - 100 s. COS84136; using exposure time - 100 s. COS84136; using exposure time - 100s. COS84136; using exposure time - 100s.