14197( 4) - 01-Oct-2015 15:38:10 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14197 Version: 4 Check-in Time: 01-Oct-2015 15:38:10 STScI Edit Number: 1 Title NGC 6273: Towards Understanding a New Class of Galactic Globular Clusters ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Christian Johnson Smithsonian Institution Astrophysical Y Observatory CoI: Dr. R. Michael Rich University of California - Los Angeles N CoI: Dr. Nelson C. Caldwell Smithsonian Institution Astrophysical N Observatory CoI: Dr. William I. Clarkson University of Michigan N ------------------------------------------------------------------------------------ Abstract Recent work combining HST photometry and ground-based spectroscopy has led to a renaissance in our understanding of Galactic globular clusters. The peculiar large light element abundance variations, discovered nearly 40 years ago by spectroscopy, hid in plain sight what HST finally revealed as a globular cluster's signature of formation: the existence, within a single globular cluster, of multiple populations with unique chemistry that trace out discrete photometric sequences. HST photometry and ground-based spectroscopy have revealed the existence of a new globular cluster class. These "anomalous" clusters are differentiated from normal globular clusters by exhibiting large (>0.1 dex) intrinsic metallicity dispersions, complex sub-giant branches, and correlated [Fe/H] and s-process abundances. Omega Centauri is the most famous and extreme example of this new class. Our new high-resolution ground-based spectroscopy demonstrates that NGC 6273, a largely unexplored but massive globular cluster, also exhibits the chemical characteristics of an anomalous cluster. Similar to Omega Cen, NGC 6273 possesses at least 2-3 stellar populations with very different [Fe/H] and s-process abundances; however, further analyses of this cluster are hindered by bulge field star contamination and strong differential reddening. Therefore, we are proposing to combine new WFC3 and archival WFPC2 data to photometrically trace the cluster's populations and isolate cluster members with proper motion cleaning. The HST photometry provides information about population ratios, radial distributions, and formation scenarios that are not possible to obtain by any other means. ------------------------------------------------------------------------------------ Observations Description ------------------------ The observations for this project consist of multiple exposures with multiple filters centered on the Galactic globular cluster NGC 6273 (M19). We are using the WFC3 instrument and the F336W, F438W, F555W, and F814W filters. The observations cover 4 orbits, and we have setup each orbit to have a different small dither position (for PSF sampling; i.e., 1 orbit per dither position). The beginning and end of each orbit consist of a "short" exposure in either the 14197( 4) - 01-Oct-2015 15:38:10 - [ 2] F438W, F555W, or F814W filters. There should be one F555W short exposure per orbit and one F438W or F814W short exposure every other orbit (i.e., F555W short is observed 4 times and F438W/F814W are observed a total of two times each). Every orbit also contains "long" exposures for each of the F336W, F438W, F555W, and F814W filters. There is also a "medium" exposure for F336W that immediately follows each long F336W exposure. These are taken in each orbit so that every long/medium exposure is taken at all four dither point positions. The goal of the short/long pattern is to get good photometry for stars ranging from ~V=13.5-23. We will be matching these new observations to archival observations taken with WFPC2 (GO-7470 and GO-8718). Since the WFC3 field-of-view is larger than WFPC2, the roll angle is not too critical. However, if possible we would prefer to match as closely as possible with the GO-7470 and GO-8718 orientation. Based on the Aladin previewer, the best orientations seem to be roll angles between 0-120 degrees, 170-195 degrees, 277-290 degrees, and 350-360 degrees. If this is too restrictive, any roll angle will still permit us to complete a majority of the science goals. ------------------------------------------------------------------------------------ 14197( 4) - 01-Oct-2015 15:38:10 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 M-19 STELLAR CLUSTER, BULGE, RA=17H02M38.7773S, J2000 V = 18 +/- 5 GLOBULAR CLUSTER DEC=-26D16'11.60" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 14197( 4) - 01-Oct-2015 15:38:10 - [ 4] Visit: 01 Visit Requirements: ORIENT 350D TO 120 D; ORIENT 170D TO 195 D; ORIENT 277D TO 290 D 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-19 WFC3/UVI ACCUM UVIS F438W FLASH=12, BLADE=A 1 10 S (10 POS TARG 0, 0 S S) Comments: Set "BLADE=A" with STScI approval. ------------------------------------------------------------------------------------------------------------------------------------ 2 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 700 S POS TARG 0, 0 S see below (566 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 350 S (350 POS TARG 0, 0 S S) ------------------------------------------------------------------------------------------------------------------------------------ 4 M-19 WFC3/UVI ACCUM UVIS F438W FLASH=12 1 350 S (350 POS TARG 0, 0 S S) ------------------------------------------------------------------------------------------------------------------------------------ 5 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=5 1 350 S (350 POS TARG 0, 0 S S) ------------------------------------------------------------------------------------------------------------------------------------ 6 M-19 WFC3/UVI ACCUM UVIS F814W FLASH=5 1 350 S POS TARG 0, 0 S see below (348 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=12, BLADE=A 1 10 S (10 POS TARG 0, 0 S S) Comments: Set "BLADE=A" with STScI approval. ------------------------------------------------------------------------------------------------------------------------------------ 8 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=12, BLADE=A 1 10 S (10 POS TARG 0.158, 0.07 S S) Comments: Set "BLADE=A" with STScI approval. ------------------------------------------------------------------------------------------------------------------------------------ 9 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 660 S POS TARG 0.158, 0.07 S see below (659 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 350 S (350 POS TARG 0.158, 0.07 S S) ------------------------------------------------------------------------------------------------------------------------------------ 11 M-19 WFC3/UVI ACCUM UVIS F438W FLASH=12 1 350 S (350 POS TARG 0.158, 0.07 S S) ------------------------------------------------------------------------------------------------------------------------------------ 12 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=5 1 350 S (350 POS TARG 0.158, 0.07 S S) ------------------------------------------------------------------------------------------------------------------------------------ 14197( 4) - 01-Oct-2015 15:38:10 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 13 M-19 WFC3/UVI ACCUM UVIS F814W FLASH=5 1 350 S POS TARG 0.158, 0.07 S see below (348 S) ------------------------------------------------------------------------------------------------------------------------------------ 14 M-19 WFC3/UVI ACCUM UVIS F438W FLASH=12, BLADE=A 1 10 S (10 POS TARG 0.158, 0.07 S S) Comments: Set "BLADE=A" with STScI approval. ------------------------------------------------------------------------------------------------------------------------------------ 15 M-19 WFC3/UVI ACCUM UVIS F814W FLASH=12, BLADE=A 1 10 S (10 POS TARG 0.099, 0.165 S S) Comments: Set "BLADE=A" with STScI approval. ------------------------------------------------------------------------------------------------------------------------------------ 16 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 700 S POS TARG 0.099, 0.165 S see below (674 S) ------------------------------------------------------------------------------------------------------------------------------------ 17 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 350 S (350 POS TARG 0.099, 0.165 S S) ------------------------------------------------------------------------------------------------------------------------------------ 18 M-19 WFC3/UVI ACCUM UVIS F438W FLASH=12 1 350 S (350 POS TARG 0.099, 0.165 S S) ------------------------------------------------------------------------------------------------------------------------------------ 19 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=5 1 350 S (350 POS TARG 0.099, 0.165 S S) ------------------------------------------------------------------------------------------------------------------------------------ 20 M-19 WFC3/UVI ACCUM UVIS F814W FLASH=5 1 350 S POS TARG 0.099, 0.165 S see below (348 S) ------------------------------------------------------------------------------------------------------------------------------------ 21 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=12, BLADE=A 1 10 S (10 POS TARG 0.099, 0.165 S S) Comments: Set "BLADE=A" with STScI approval. ------------------------------------------------------------------------------------------------------------------------------------ 22 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=12, BLADE=A 1 10 S (10 POS TARG -0.060, 0.095 S S) ------------------------------------------------------------------------------------------------------------------------------------ 23 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 700 S POS TARG -0.060, 0.095 S see below (685 S) ------------------------------------------------------------------------------------------------------------------------------------ 24 M-19 WFC3/UVI ACCUM UVIS F336W FLASH=12 1 350 S (350 POS TARG -0.060, 0.095 S S) ------------------------------------------------------------------------------------------------------------------------------------ 25 M-19 WFC3/UVI ACCUM UVIS F438W FLASH=12 1 350 S (350 POS TARG -0.060, 0.095 S S) ------------------------------------------------------------------------------------------------------------------------------------ 14197( 4) - 01-Oct-2015 15:38:10 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 26 M-19 WFC3/UVI ACCUM UVIS F555W FLASH=5 1 350 S (350 POS TARG -0.060, 0.095 S S) ------------------------------------------------------------------------------------------------------------------------------------ 27 M-19 WFC3/UVI ACCUM UVIS F814W FLASH=5 1 350 S POS TARG -0.060, 0.095 S see below (348 S) ------------------------------------------------------------------------------------------------------------------------------------ 28 M-19 WFC3/UVI ACCUM UVIS F814W FLASH=12, BLADE=A 1 10 S (10 POS TARG -0.060, 0.095 S S) Comments: Set "BLADE=A" with STScI approval. ------------------------------------------------------------------------------------------------------------------------------------ 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-19 1 WFC3/UVI ACCUM UVIS F438W none none none none 1 N/A S M-19 2 WFC3/UVI ACCUM UVIS F336W none none none none 1 566.0 S S M-19 3 WFC3/UVI ACCUM UVIS F336W none none none none 1 N/A S M-19 4 WFC3/UVI ACCUM UVIS F438W none none none none 1 N/A S M-19 5 WFC3/UVI ACCUM UVIS F555W none none none none 1 N/A S M-19 6 WFC3/UVI ACCUM UVIS F814W none none none none 1 348.0 S S M-19 7 WFC3/UVI ACCUM UVIS F555W none none none none 1 N/A S M-19 8 WFC3/UVI ACCUM UVIS F555W none none none none 2 N/A S M-19 9 WFC3/UVI ACCUM UVIS F336W none none none none 2 659.0 S S M-19 10 WFC3/UVI ACCUM UVIS F336W none none none none 2 N/A S M-19 11 WFC3/UVI ACCUM UVIS F438W none none none none 2 N/A S M-19 12 WFC3/UVI ACCUM UVIS F555W none none none none 2 N/A S M-19 13 WFC3/UVI ACCUM UVIS F814W none none none none 2 348.0 S S M-19 14 WFC3/UVI ACCUM UVIS F438W none none none none 2 N/A S M-19 15 WFC3/UVI ACCUM UVIS F814W none none none none 3 N/A S 14197( 4) - 01-Oct-2015 15:38:10 - [ 7] 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-19 16 WFC3/UVI ACCUM UVIS F336W none none none none 3 674.0 S S M-19 17 WFC3/UVI ACCUM UVIS F336W none none none none 3 N/A S M-19 18 WFC3/UVI ACCUM UVIS F438W none none none none 3 N/A S M-19 19 WFC3/UVI ACCUM UVIS F555W none none none none 3 N/A S M-19 20 WFC3/UVI ACCUM UVIS F814W none none none none 3 348.0 S S M-19 21 WFC3/UVI ACCUM UVIS F555W none none none none 3 N/A S M-19 22 WFC3/UVI ACCUM UVIS F555W none none none none 4 N/A S M-19 23 WFC3/UVI ACCUM UVIS F336W none none none none 4 685.0 S S M-19 24 WFC3/UVI ACCUM UVIS F336W none none none none 4 N/A S M-19 25 WFC3/UVI ACCUM UVIS F438W none none none none 4 N/A S M-19 26 WFC3/UVI ACCUM UVIS F555W none none none none 4 N/A S M-19 27 WFC3/UVI ACCUM UVIS F814W none none none none 4 348.0 S S M-19 28 WFC3/UVI ACCUM UVIS F814W none none none none 4 N/A S 14197( 4) - 01-Oct-2015 15:38:10 - [ 8] Summary Form for Proposal 14197 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BLADE=A, FLASH=12, FLASH=5 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 170D TO 195 D, ORIENT 277D TO 290 D, ORIENT 350D TO 120 D, POS TARG -0.060, 0.095, POS TARG 0, 0, POS TARG 0.099, 0.165, POS TARG 0.158, 0.07 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W, F438W, F555W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names M-19 ------------------------------------------------------------------------------------------------------------------------------------