13295( 13) - 28-Feb-2014 20:29:33 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13295 Version: 13 Check-in Time: 28-Feb-2014 20:29:33 STScI Edit Number: 10 Title Do the globular clusters in the Fornax dSph have multiple stellar populations? ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Soeren S. Larsen Radboud Universiteit Nijmegen Y CoI: Prof. Jean P. Brodie University of California - Santa Cruz N CoI: Prof. Jay Strader Michigan State University N CoI: Dr. Frank Grundahl Aarhus University N ------------------------------------------------------------------------------------ Abstract We propose to obtain WFC3 F343N-band imaging of the four most metal-poor globular clusters (GCs) in the Fornax dwarf spheroidal galaxy. With these data, we will establish whether red giant branch (RGB) stars in the clusters show a spread in their abundances of nitrogen. This will tell us whether the Fornax GCs host multiple stellar populations, as appears to be the case in most Galactic GCs. The Fornax dSph is of special interest in this context because a very large fraction (about 20%-25%) of its metal-poor stars ([Fe/H]<-2) belong to the four most metal-poor GCs. N-body simulations suggest it is highly unlikely that a large number of field stars have been lost due to tidal interaction with the Milky Way. The GCs could therefore, at most, have been a factor of 5 more massive initially, or otherwise more metal-poor field stars should be observed. This result is in tension with some leading scenarios for the origin of multiple populations via self-enrichment in GCs, which require GCs to have been at least a factor of 10 more massive initially. It is therefore crucial to establish whether the Fornax GCs do indeed host multiple stellar populations, and in what proportion. If they do, alternative explanations for the origin of multiple populations would have to be sought, which do not require a large number of first-generation stars to have been lost from the clusters (for example, by invoking a top-heavy first-generation IMF or accretion of additional gas). If they do not, this would have the interesting consequence that GC formation in the Fornax dSph differed significantly from that in the Milky Way. ------------------------------------------------------------------------------------ Observations Description ------------------------ Each of the four most metal-poor globular clusters in the Fornax dSph will be observed in F343N for four orbits. We will use a four-point box dither pattern (one point per orbit) with a two-point line sub-pattern (each orbit split into two exposures). Additionally, the globular cluster M15 will be observed in F343N, F555W and F814W as a calibration target. Real Time Justification ----------------------- 13295( 13) - 28-Feb-2014 20:29:33 - [ 2] Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 13295( 13) - 28-Feb-2014 20:29:33 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 FORNAX-1 STELLAR CLUSTER, RA=02H37M1.9008S, J2000 V = 15.6 GLOBULAR CLUSTER DEC=-34D11'1.00" Reference Frame: Other: NED Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 2 FORNAX-2 STELLAR CLUSTER, RA=02H38M44.0000S, J2000 V = 13.5 GLOBULAR CLUSTER DEC=-34D48'30.00" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 3 FORNAX-3 STELLAR CLUSTER, RA=02H39M48.1500S, J2000 V = 12.6 GLOBULAR CLUSTER DEC=-34D15'28.20" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 5 FORNAX-5 STELLAR CLUSTER, RA=02H42M21.1110S, J2000 V = 13.4 GLOBULAR CLUSTER DEC=-34D06'5.80" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 6 M-15 STELLAR CLUSTER, RA=21H29M58.3300S, J2000 V = 6.20 +/- 0.1 GLOBULAR CLUSTER DEC=+12D10'1.20" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 13295( 13) - 28-Feb-2014 20:29:33 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type BOX WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER DITHER Number_Of_Points 4 2 Point_Spacing 0.173 0.145 Line_Spacing 0.112 Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 23.884 46.84 Angle_Between_Sides 81.785 Center_Pattern NO NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 4 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 13295( 13) - 28-Feb-2014 20:29:33 - [ 5] 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 FORNAX-1 WFC3/UVI ACCUM UVIS2-FIX F343N FLASH=10 1 1390 S POS TARG 40, 0; PATTERN S see below 2 1 (11498 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 | ------------------------------------------------------------------------------------------------------------------------------------ FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 1 none none 1 1396.0 S S X FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 2 none none 1 1396.0 S S X FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 1 none none 2 1451.0 S S X FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 2 none none 2 1451.0 S S X FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 1 none none 3 1451.0 S S X FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 2 none none 3 1451.0 S S X FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 1 none none 4 1451.0 S S X FORNAX-1 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 2 none none 4 1451.0 S S X 13295( 13) - 28-Feb-2014 20:29:33 - [ 6] 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 FORNAX-2 WFC3/UVI ACCUM UVIS2-FIX F343N FLASH=10 1 1390 S POS TARG 40, 0; PATTERN S see below 2 1 (11498 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 | ------------------------------------------------------------------------------------------------------------------------------------ FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 1 none none 1 1396.0 S S X FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 2 none none 1 1396.0 S S X FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 1 none none 2 1451.0 S S X FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 2 none none 2 1451.0 S S X FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 1 none none 3 1451.0 S S X FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 2 none none 3 1451.0 S S X FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 1 none none 4 1451.0 S S X FORNAX-2 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 2 none none 4 1451.0 S S X 13295( 13) - 28-Feb-2014 20:29:33 - [ 7] 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 FORNAX-3 WFC3/UVI ACCUM UVIS2-FIX F343N FLASH=10 1 1390 S POS TARG 40, 0; PATTERN S see below 2 1 (11498 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 | ------------------------------------------------------------------------------------------------------------------------------------ FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 1 none none 1 1396.0 S S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 2 none none 1 1396.0 S S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 1 none none 2 1451.0 S S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 2 none none 2 1451.0 S S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 1 none none 3 1451.0 S S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 2 none none 3 1451.0 S S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 1 none none 4 1451.0 S S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 2 none none 4 1451.0 S S X 13295( 13) - 28-Feb-2014 20:29:33 - [ 8] Visit: 04 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 FORNAX-5 WFC3/UVI ACCUM UVIS2-FIX F343N FLASH=10 1 1390 S POS TARG 40, 0; PATTERN S see below 2 1 (11498 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 | ------------------------------------------------------------------------------------------------------------------------------------ FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 1 none none 1 1396.0 S S X FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 2 none none 1 1396.0 S S X FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 1 none none 2 1451.0 S S X FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 2 none none 2 1451.0 S S X FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 1 none none 3 1451.0 S S X FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 3 2 none none 3 1451.0 S S X FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 1 none none 4 1451.0 S S X FORNAX-5 1 WFC3/UVI ACCUM UVIS2-FI F343N 4 2 none none 4 1451.0 S S X 13295( 13) - 28-Feb-2014 20:29:33 - [ 9] Visit: 05 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 M-15 WFC3/UVI ACCUM UVIS2 F343N FLASH=12 1 350 S (700 PATTERN 3 1 S S) ------------------------------------------------------------------------------------------------------------------------------------ 2 M-15 WFC3/UVI ACCUM UVIS2 F555W FLASH=12 1 10 S (20 PATTERN 3 2 S S) ------------------------------------------------------------------------------------------------------------------------------------ 3 M-15 WFC3/UVI ACCUM UVIS2 F814W FLASH=12 1 10 S (20 PATTERN 3 3 S 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 | ------------------------------------------------------------------------------------------------------------------------------------ M-15 1 WFC3/UVI ACCUM UVIS2 F343N 1 none none none 1 N/A S M-15 1 WFC3/UVI ACCUM UVIS2 F343N 2 none none none 1 N/A S M-15 2 WFC3/UVI ACCUM UVIS2 F555W 1 none none none 1 N/A S M-15 2 WFC3/UVI ACCUM UVIS2 F555W 2 none none none 1 N/A S M-15 3 WFC3/UVI ACCUM UVIS2 F814W 1 none none none 1 N/A S M-15 3 WFC3/UVI ACCUM UVIS2 F814W 2 none none none 1 N/A S 13295( 13) - 28-Feb-2014 20:29:33 - [ 10] Visit: 53 Visit Requirements: On Hold Comments: Additional Comments: HOPR repeat of 2nd orbit from Visit 03 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 FORNAX-3 WFC3/UVI ACCUM UVIS2-FIX F343N FLASH=10 1 1390 S POS TARG 40.158, 0.07; S (2780 S) GS ACQ SCENARIO BASE1B3; PATTERN 4 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 1 none none none 1 N/A S X FORNAX-3 1 WFC3/UVI ACCUM UVIS2-FI F343N 2 none none none 1 N/A S X 13295( 13) - 28-Feb-2014 20:29:33 - [ 11] Summary Form for Proposal 13295 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2, UVIS2-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=10, FLASH=12 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, PATTERN 2 1, PATTERN 3 1, PATTERN 3 2, PATTERN 3 3, PATTERN 4 1, POS TARG 40, 0, POS TARG 40.158, 0.07 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F343N, F555W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names FORNAX-1, FORNAX-2, FORNAX-3, FORNAX-5, M-15 ------------------------------------------------------------------------------------------------------------------------------------