Submission for mid-cycle-25 proposal. -1893518986 Assigned ID: 1645 ----- Attempting Submission 1 (Tue Mar 13 22:19:14 GMT 2018) ----- Resubmission of Phase 2 for 15462. Changed STIS wavecal to a third exposure in occultation to maximize science exposure time (thx to Dan Welty for the advice). 1620081197 ----- Attempting Submission 1 (Thu May 17 21:49:24 GMT 2018) ----- HST Phase II Proposal 15462 (15462_superdla.apt) successfully submitted. Receipt: # 15462-1 ----- Attempting Submission 2 (Fri May 18 16:01:20 GMT 2018) ----- The Super-DLA in our Galactic Backyard During routine AGN observations in Cycle 25, we detected a damped Lyman-alpha absorber (DLA) at redshift z = 0 apparently arising in the Magellanic Stream. This local DLA has an abnormally high neutral hydrogen column density, log N(HI) = 23.2, approximately 500 times higher than the typical maximum values in the Magellanic Stream (log N(HI) = 20.5) and 100 times that of large HI clouds in the Galactic ISM. However, there is no clear evidence of dust or molecules despite the unprecedented column density. Given its extreme properties (high neutral column, low metallicity, low dust content, and apparent lack of molecules) we need to observe this DLA in greater detail. We propose to observe the near-UV continuum to constrain dust absorption in the 2175A feature (STIS/G230L; 1 orbit). In the far-UV we will search for absorption from H2, CO, and low-ionization metals (COS/G130M/1222; 5 orbits). We also hope to clarify the location of the DLA (Galactic disk vs Magellanic Stream) through line-profile kinematics and possible changes arising from proper motion. The good fortune of having a UV-bright QSO behind this low-redshift DLA makes it a unique system. Before we submit a manuscript to Nature, we want to confirm the H I column density and physical characteristics, including the profile recovery shortward of 1130 Ang, the molecular content, and the continuum longward of 1900 Ang where our COS/G140L spectrum becomes unusably noisy. Two spectral observations (G230L and G130M) totaling 6 orbits will confirm the large DLA column density and detect (or limit) its molecular content in far-UV absorption lines of H2 and in the shorter-wavelength UV lines of CO. We will also search for the 2175 Ang dust feature and derive the metallicity pattern through interstellar absorption lines (C II, Si II, Fe II, N I, Al II, Mg II, C IV, Si IV). The G130M should have sufficient resolution to separate Galactic ISM lines from those in the Stream, using the N I triplet lines at 1134-1135 Ang, Si II 1260 Ang, and C II 1334-1335 Ang. The wavelength coverage of G130M in the 1222 Ang setting is 1068-1208 Ang (Segment B) and 1223-1364 Ang (Segment A). We propose to observe this intermediate-redshift (z = 2.18) QSO with both COS and STIS. We request STIS/G230L (1 orbit) to yield S/N~20 per resel at 2200 Ang. With COS/G130M (5 orbits with 1222 setting) straddling our original COS/G140L spectrum we will obtain S/N=5-10 in the wings of the DLA and S/N= 4-6 (1108-1110 Ang) where the longest-wavelength H2 Lyman (0-0) R(0) and R(1) lines are located. Galaxies and the IGM 3 false true false false false false SUPPORTED GALAXY LYMAN ALPHA CLOUD QSO TIDAL TAIL NO HE0025-4047 J2000 J2000 F(1500)=1.8-15 erg/cm2/s/Ang STIS/NUV-MAMA Spectroscopic No No G230L 2376 COS/FUV Spectroscopic No No G130M 1222 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. /private/var/folders/28/q7n1k9mx06q9bdhm39kq5pn80000gn/T/OPVisit1756141789977640009.xml Single orbit of STIS/G230L observation. Target ACQ for STIS should be straight-forward and not require a PEAK-ACQ(?). (Tic-Visit :proposal-id 15462 :visit-id "01" :proposal-version -1 :trans-version "20171009" :date "18-May-2018 09:41:58.0" :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 296144 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15462 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15462 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2965 :al-overhead-at-end 0 :internal-dur-at-end 582 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3298 :pcs-gap 0 ) true 1 0 ETC gives exposure time of 1.5 seconds. Doubling it here to guard against (unlikely) flux changes. The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. /Users/danforth/Desktop/OP-cache/15462_superdla-v02.xml Three orbits of COS/G140M/1222 observations. Minimizing number of exposures to maximize S/N (a la Keeney et al. 2012) while still using all four FP positions. Target ACQ procedure cloned from successful 15084 V1 procedure (COS/G140L obs of same object). (Tic-Visit :proposal-id 15462 :visit-id "02" :proposal-version -1 :trans-version "20171009" :date "16-May-2018 12:59:04.0" :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 356720 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15462 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15462 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2964 :al-overhead-at-end 0 :internal-dur-at-end 76 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3298 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15462 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3076 :al-overhead-at-end 0 :internal-dur-at-end 76 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3298 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15462 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3076 :al-overhead-at-end 0 :internal-dur-at-end 369 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3298 :pcs-gap 0 ) true 3 0 F(1530A)=1.6e-15, MIRRORA=4.7 sec. Copied from successful program 15084 v1 observations (COS/G140L) S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. /Users/danforth/Desktop/OP-cache/15462_superdla-v03.xml Two orbits of COS/G140M/1222 observations. Minimizing number of exposures to maximize S/N (a la Keeney et al. 2012) while still using all four FP positions. Target ACQ procedure cloned from successful 15084 V1 procedure (COS/G140L obs of same object). (Tic-Visit :proposal-id 15462 :visit-id "03" :proposal-version -1 :trans-version "20171009" :date "17-May-2018 11:25:19.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 243648 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15462 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15462 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2964 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3298 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15462 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3076 :al-overhead-at-end 0 :internal-dur-at-end 388 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3298 :pcs-gap 0 ) true 2 0 F(1530A)=1.6e-15, MIRRORA=4.7 sec. Copied from successful program 15084 v1 observations (COS/G140L) S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8