15462( 2) - 18-May-2018 18:01:22 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15462 Version: 2 Check-in Time: 18-May-2018 18:01:22 STScI Edit Number: 0 Title The Super-DLA in our Galactic Backyard ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. J. Michael Shull University of Colorado at Boulder Y CoI: Dr. Charles Danforth University of Colorado at Boulder Y CoI: Prof. John Thomas Stocke University of Colorado at Boulder N ------------------------------------------------------------------------------------ Abstract 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. ------------------------------------------------------------------------------------ Observations Description ------------------------ 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 15462( 2) - 18-May-2018 18:01:22 - [ 2] (1108-1110 Ang) where the longest-wavelength H2 Lyman (0-0) R(0) and R(1) lines are located. ------------------------------------------------------------------------------------ 15462( 2) - 18-May-2018 18:01:22 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 Q0025-4047 GALAXY, LYMAN ALPHA RA=00H27M42.8300S +/- .1", J2000 Z = 2.18 V = 17.14 F(1500)=1.8-15 erg/cm2/s/Ang CLOUD, QSO, TIDAL TAIL DEC=-40D31'0.60" +/- .1" Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 15462( 2) - 18-May-2018 18:01:22 - [ 4] Visit: 01 (V1 - STIS) Visit Requirements: On Hold Comments: Additional Comments: Single orbit of STIS/G230L observation. Target ACQ for STIS should be straight-forward and not require a PEAK-ACQ(?). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 Q0025-4047 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 3 S (3 S) Comments: ETC gives exposure time of 1.5 seconds. Doubling it here to guard against (unlikely) flux changes. ------------------------------------------------------------------------------------------------------------------------------------ 2 Q0025-4047 STIS/NUV TIME-TA 52X0.2 G230L 2376 BUFFER-TIME=800, WAVECAL=NO 1 2000 S -MAMA G see below (2530 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/NUV ACCUM 52X0.2 G230L 2376 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ Q0025-4047 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A Q0025-4047 2 STIS/NUV TIME-TA 52X0.2 G230L 2376 none none none none 1 2530.0 S -MAMA G WAVE 3 STIS/NUV ACCUM 52X0.2 G230L 2376 none none none none 1 N/A -MAMA 15462( 2) - 18-May-2018 18:01:22 - [ 5] Visit: 02 (V2 - COS 1) Visit Requirements: On Hold Comments: Additional Comments: 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). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 Q0025-4047 COS/NUV ACQ/IMA PSA MIRRORB 1 98 S (98 GE S) Comments: F(1530A)=1.6e-15, MIRRORA=4.7 sec. Copied from successful program 15084 v1 observations (COS/G140L) ------------------------------------------------------------------------------------------------------------------------------------ 2 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=1 1 1000 S G see below (1215 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ 3 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=2 1 1000 S G see below (1071 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ 4 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=3 1 2500 S G see below (3012 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ 5 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=4 1 2500 S G see below (3012 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ Q0025-4047 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE 15462( 2) - 18-May-2018 18:01:22 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ Q0025-4047 2 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 1215.0 S G Q0025-4047 3 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 1071.0 S G Q0025-4047 4 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 3012.0 S G Q0025-4047 5 COS/FUV TIME-TA PSA G130M 1222 none none none none 3 3012.0 S G 15462( 2) - 18-May-2018 18:01:22 - [ 7] Visit: 03 (V3 - COS 2) Visit Requirements: On Hold Comments: Additional Comments: 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). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 Q0025-4047 COS/NUV ACQ/IMA PSA MIRRORB 1 98 S (98 GE S) Comments: F(1530A)=1.6e-15, MIRRORA=4.7 sec. Copied from successful program 15084 v1 observations (COS/G140L) ------------------------------------------------------------------------------------------------------------------------------------ 2 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=1 1 1000 S G see below (1143 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ 3 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=2 1 1000 S G see below (1143 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ 4 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=3 1 1200 S G see below (1425 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ 5 Q0025-4047 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2000, FP-POS=4 1 1200 S G see below (1425 S) Comments: S/N for 1ks exp=2.2 S/N for 12.5 ks exp (5 orbits total) ~ 8 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ Q0025-4047 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE 15462( 2) - 18-May-2018 18:01:22 - [ 8] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ Q0025-4047 2 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 1143.0 S G Q0025-4047 3 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 1143.0 S G Q0025-4047 4 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 1425.0 S G Q0025-4047 5 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 1425.0 S G 15462( 2) - 18-May-2018 18:01:22 - [ 9] Summary Form for Proposal 15462 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, F28X50LP, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV, STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, BUFFER-TIME=2000, BUFFER-TIME=800, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, WAVECAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G230L, MIRROR, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names Q0025-4047, WAVE ------------------------------------------------------------------------------------------------------------------------------------