13840( 3) - 15-Sep-2014 15:18:19 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13840 Version: 3 Check-in Time: 15-Sep-2014 15:18:19 STScI Edit Number: 0 Title The Smith Cloud: Galactic or Extragalactic? ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Andrew J. Fox Space Telescope Science Institute - ESA Y CoI: Dr. Kenneth Sembach Space Telescope Science Institute N CoI: Dr. Felix J. Lockman National Science Foundation N CoI: Dr. Bart P. Wakker University of Wisconsin - Madison N CoI: Prof. Brice Menard The Johns Hopkins University N CoI: Dr. Nicolas Lehner University of Notre Dame N CoI: Dr. Alex S Hill CSIRO, Australia Telescope National N Facility CoI: Dr. Kathleen A Barger University of Notre Dame N CoI: Prof. Fabian Heitsch University of North Carolina at Chapel N Hill CoI: David Vincent Stark University of North Carolina at Chapel N Hill CoI: Dr. Mubdi Rahman The Johns Hopkins University N CoI: Dr. Robert A. Benjamin University of Wisconsin - Whitewater N ------------------------------------------------------------------------------------ Abstract The Milky Way is surrounded by a population of gaseous high-velocity clouds (HVCs), which play an important role in bringing fresh fuel for star formation into the disk. The Smith Cloud is an HVC in an advanced state of accretion, only ~30 Myr away from impacting the Galactic plane. It is unique among HVCs in having a known distance (12.4 kpc) and a well-constrained 3D velocity (300 km/s), but we do not yet know its metallicity, which would distinguish between Galactic (metal-enriched) and extragalactic (metal-poor) origins. Here we propose a program to measure the Smith Cloud's metallicity using HST/COS spectra of three AGN lying behind the Cloud and its wake. Combining the UV metal-line (O I and S II) column densities with existing H I column densities will lead to precise abundance measurements for the Smith Cloud, directly constraining its origin. In addition, the relative strength of depleted (Fe II, Si II) to undepleted (S II) UV absorption lines will be used to infer its dust content. Finally, we will search for variation in the ionization level and kinematics between the three sight lines, which would indicate a disruptive encounter with the hot Galactic corona. ------------------------------------------------------------------------------------ Observations Description ------------------------ This is a nine-orbit COS/G130M spectroscopic program to study the chemical and physical properties of the Smith Cloud, a high-velocity cloud (HVC) falling onto the Galactic disk. The program observes three QSOs, with a single three-orbit visit on each QSO. Each target is fairly faint in the UV, with F_1300 between 0.5e-14 and 0.8e-14 erg/cm^2/s^-1/A^-1, so there are no bright-object concerns (all three fields pass BOT checks with both GSC II and 13840( 3) - 15-Sep-2014 15:18:19 - [ 2] GALEX catalogs). All four FP-POS positions are used within each visit with the 1291 CENWAVE setting. ------------------------------------------------------------------------------------ 13840( 3) - 15-Sep-2014 15:18:19 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PG2112+059 ISM, ABSORPTION LINE RA=21H14M52.5871S +/- 0.1", J2000 V = 15.77 F_1300=0.75e-14 (cgs) SYSTEM, HIGH VELOCITY DEC=+06D07'42.33" +/- 0.1" CLOUD Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 2 RXJ2043.1+03 ISM, ABSORPTION LINE RA=20H43M6.2800S +/- 0.5", J2000 V = 17.0 F_1300=0.55e-14 (cgs) 24 SYSTEM, HIGH VELOCITY DEC=+03D24'51.50" +/- 0.5" CLOUD Reference Frame: ICRS Comments: SIMBAD coordinates did not match position of target on finder charts. DEC changed by +1.5", RA changed by +0.08s to match target. ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ2139.7+02 ISM, ABSORPTION LINE RA=21H39M44.1873S +/- 0.1", J2000 V = 16.1 F_1300=0.79e-14 (cgs) 46 SYSTEM, HIGH VELOCITY DEC=+02D46'5.40" +/- 0.1" CLOUD Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 13840( 3) - 15-Sep-2014 15:18:19 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: 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 PG2112+059 COS/FUV ACQ/SEA PSA G130M 1291 SCAN-SIZE=2, CENTER=FLUX-WT, 1 8 S (8 S) RCH STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ 2 PG2112+059 COS/FUV ACQ/PEA PSA G130M 1291 1 8 S (8 S) KXD ------------------------------------------------------------------------------------------------------------------------------------ 3 PG2112+059 COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=5.0, STEP-SIZE=0.9, 1 8 S (8 S) KD CENTER=FLUX-WT-FLR ------------------------------------------------------------------------------------------------------------------------------------ 4 PG2112+059 COS/FUV TIME-TA PSA G130M 1291 FP-POS=1, BUFFER-TIME=2205 1 2205 S G (2205 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 PG2112+059 COS/FUV TIME-TA PSA G130M 1291 FP-POS=2, BUFFER-TIME=2424 1 2935 S G (2935 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 PG2112+059 COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, BUFFER-TIME=1375 1 1375 S G (1375 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 PG2112+059 COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, BUFFER-TIME=1375 1 1375 S G (1375 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ PG2112+059 1 COS/FUV ACQ/SEA PSA G130M 1291 none none none none 1 N/A RCH PG2112+059 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD PG2112+059 3 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD PG2112+059 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G PG2112+059 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G PG2112+059 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G PG2112+059 7 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G 13840( 3) - 15-Sep-2014 15:18:19 - [ 5] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: 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 RXJ2043.1+0 COS/FUV ACQ/SEA PSA G130M 1291 SCAN-SIZE=2, CENTER=FLUX-WT, 1 14 S (14 324 RCH STEP-SIZE=1.767 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RXJ2043.1+0 COS/FUV ACQ/PEA PSA G130M 1291 1 14 S (14 324 KXD S) ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ2043.1+0 COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=5.0, STEP-SIZE=0.9, 1 14 S (14 324 KD CENTER=FLUX-WT-FLR S) ------------------------------------------------------------------------------------------------------------------------------------ 4 RXJ2043.1+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=1, BUFFER-TIME=2148 1 2148 S 324 G (2148 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 RXJ2043.1+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=2, BUFFER-TIME=2935 1 2935 S 324 G (2935 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 RXJ2043.1+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, BUFFER-TIME=1375 1 1375 S 324 G (1375 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 RXJ2043.1+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, BUFFER-TIME=1375 1 1375 S 324 G (1375 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ RXJ2043.1+0324 1 COS/FUV ACQ/SEA PSA G130M 1291 none none none none 1 N/A RCH RXJ2043.1+0324 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD RXJ2043.1+0324 3 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD RXJ2043.1+0324 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G RXJ2043.1+0324 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G RXJ2043.1+0324 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G RXJ2043.1+0324 7 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G 13840( 3) - 15-Sep-2014 15:18:19 - [ 6] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: 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 RXJ2139.7+0 COS/FUV ACQ/SEA PSA G130M 1291 SCAN-SIZE=2, CENTER=FLUX-WT, 1 12 S (12 246 RCH STEP-SIZE=1.767 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RXJ2139.7+0 COS/FUV ACQ/PEA PSA G130M 1291 1 12 S (12 246 KXD S) ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ2139.7+0 COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=5.0, STEP-SIZE=0.9, 1 12 S (12 246 KD CENTER=FLUX-WT-FLR S) ------------------------------------------------------------------------------------------------------------------------------------ 4 RXJ2139.7+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=1, BUFFER-TIME=2168 1 2168 S 246 G (2168 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 RXJ2139.7+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=2, BUFFER-TIME=2791 1 2935 S 246 G (2935 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 RXJ2139.7+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, BUFFER-TIME=1375 1 1375 S 246 G (1375 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 RXJ2139.7+0 COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, BUFFER-TIME=1375 1 1375 S 246 G (1375 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ RXJ2139.7+0246 1 COS/FUV ACQ/SEA PSA G130M 1291 none none none none 1 N/A RCH RXJ2139.7+0246 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD RXJ2139.7+0246 3 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD RXJ2139.7+0246 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G RXJ2139.7+0246 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G RXJ2139.7+0246 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G RXJ2139.7+0246 7 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G 13840( 3) - 15-Sep-2014 15:18:19 - [ 7] Summary Form for Proposal 13840 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1375, BUFFER-TIME=2148, BUFFER-TIME=2168, BUFFER-TIME=2205, BUFFER-TIME=2424, BUFFER-TIME=2791, BUFFER-TIME=2935, CENTER=FLUX-WT, CENTER=FLUX-WT-FLR, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, NUM-POS=5.0, SCAN-SIZE=2, STEP-SIZE=0.9, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M ------------------------------------------------------------------------------------------------------------------------------------ Target Names PG2112+059, RXJ2043.1+0324, RXJ2139.7+0246 ------------------------------------------------------------------------------------------------------------------------------------