16864( 2) - 22-Nov-2021 15:15:43 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16864 Version: 2 Check-in Time: 22-Nov-2021 15:15:43 STScI Edit Number: 0 Title WFC3/IR Time-Dependent Sensitivity in Staring Mode (Clusters) ------------------------------------------------------------------------------------ Type Cycle CAL/WFC3 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Varun Bajaj Space Telescope Science Institute Y CoI: Dr. Annalisa Calamida Space Telescope Science Institute Y CoI: Ms. Jennifer Mack Space Telescope Science Institute Y CoI: Dr. Debopam Som Space Telescope Science Institute Y ------------------------------------------------------------------------------------ Abstract The IR grism flux monitor shows a sensitivity loss of 0.12+/-0.01%/yr in G102 and 0.06+/-0.01%/yr in G141. Observations of flux standards in the IR filters, however, show no evidence of any loss over time, but the repeatability is limited by systematic errors of +/- 1%. Scanned observations of M35 from 2015-2020 show marginal losses of 0.024+/- 0.008%/yr in F140W, but these data show a large scatter which may be related to detector preconditioning. Cluster observations allow for the measurement of many more stars, and photometry of the core Omega-Cen used for distortion monitoring suggests losses of 0.23 +/- 0.03%/yr in F160W, but crowding may play an effect on the results. Recent observations of a less dense stellar field in M4 in F110W suggest losses of 0.13 +/- 0.02%/yr (first images only) and 0.20 +/- 0.03%/yr (all images), but these consist of only 4 visits. We propose continued monitoring of M4 at a ~6 month cadence. Two additional clusters are requested: the NGC104 field 6' from the core with F160W data from 2009-2013 and an Omega-Cen field 17' from the core with F110W & F160W images from 2016-2018, both of which mimic the observation strategy from the respective preceeding epochs, to eliminate systematics from differing observing modes. ------------------------------------------------------------------------------------ Observations Description ------------------------ In general, these observations copy the targets, sample sequences, NSamps, and orbit structure of previously obtained WFC3/IR observations, as this yields the fewest systematics when attempting to measure sensitivity losses over time. We propose two visits of WFC3/IR observations of M4. Both visits will be executed with the same exposure parameters, but will be scheduled approximately 6 months apart (Summer/Fall 2022 and Winter/Spring 2023), to best sample the time dependence of the sensitivity withtin the window in which the target is visible. Each visit will be composed of 4 exposures, the first two in F110W and the latter two in F160W. The F110W images will use 14 samples with the SPARS50 sample sequence to match those taken in 16512. To mitigate persistence, POSTARGS of 2.5 arcseconds in X and Y will be used between exposures, to match the observations of 16512. The visits are constrained to be 180 degrees apart, to be able to discern flat field effects. The orients of visits will match the respective visits from 16512 to separate flat field effects from sensitivity loss. The target coordinates for Visit 01 have been adjusted from 16512 to more 16864( 2) - 22-Nov-2021 15:15:43 - [ 2] closely match the field of view in Visit 02 as well as prior observations. The two visit of WFC3/IR observations of Omega Centauri are configured to match the IR obsevations of 14662 (Visits 31 and 39 for F110W and F160W, respectively). In this case however, WFC3/IR is used as the primary instrument (as opposed to 14662 where ACS/WFC was the primary and WFC3/IR was the parallel). The roll angle was also constrained to be within 2.5 degrees of the visits from 14662, to eliminate flat field effects. The target positions and postargs were adjusted accordingly to account for the switch from parallel to prime. Visit 04 is constrained to occur at least 3 days after Visit 03 to prevent these two visits from being scheduled consecutively (which would introduce persistence). The visit of WFC3/IR observations of 47 Tuc was configued to match 13563 Visit 01. The roll was not constrained, as prervious observations were taken with a large range of roll angles. The last exposure in the visit was changed (relative to 13563 Visit 01) from a dark to another F160W exposure, as we will not be performing analysis on the darks, and thus the orbit time can be better spent taking one more external exposure, without changing the observational configuration for the previous exposures. The last exposure is also dithered by approximately 40 pixels to mitigate persistence. ------------------------------------------------------------------------------------ 16864( 2) - 22-Nov-2021 15:15:43 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 M-4-V1 STELLAR CLUSTER, RA=16H23M41.5344S, J2000 V = 5.9 GLOBULAR CLUSTER DEC=-26D29'54.22" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 M-4 STELLAR CLUSTER, RA=16H23M41.7160S, J2000 V = 5.9 GLOBULAR CLUSTER DEC=-26D30'19.01" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC-5139B STELLAR CLUSTER, RA=13H25M34.4378S, J2000 V = 5.33 GLOBULAR CLUSTER DEC=-47D28'26.32" Reference Frame: Other: SIMBAD ------------------------------------------------------------------------------------------------------------------------------------ 4 47TUC CALIBRATION, DETECTOR RA=00H22M27.8446S +/- 0.1", J2000 V = 22.0 LINEARITY TEST DEC=-72D04'4.75" +/- 0.1" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 16864( 2) - 22-Nov-2021 15:15:43 - [ 4] Visit: 01 Visit Requirements: ORIENT 101.0D TO 101.0 D; BETWEEN 20-AUG-2022:00:00:00 AND 15-SEP-2022:00:00:00 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-4-V1 WFC3/IR MULTIAC IR-UVIS-F F110W SAMP-SEQ=SPARS50, NSAMP=14 1 DEF POS TARG -5, 5 CUM IX (652.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 M-4-V1 WFC3/IR MULTIAC IR-UVIS-F F110W SAMP-SEQ=SPARS50, NSAMP=14 1 DEF POS TARG -2.5, 2.5 CUM IX (652.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 M-4-V1 WFC3/IR MULTIAC IR-UVIS-F F160W SAMP-SEQ=SPARS50, NSAMP=13 1 DEF POS TARG 0, 0 CUM IX (602.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 M-4-V1 WFC3/IR MULTIAC IR-UVIS-F F160W SAMP-SEQ=SPARS50, NSAMP=13 1 DEF POS TARG -7.5, 7.5 CUM IX (602.938 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-4-V1 1 WFC3/IR MULTIAC IR-UVIS- F110W none none none none 1 N/A CUM FIX M-4-V1 2 WFC3/IR MULTIAC IR-UVIS- F110W none none none none 1 N/A CUM FIX M-4-V1 3 WFC3/IR MULTIAC IR-UVIS- F160W none none none none 1 N/A CUM FIX M-4-V1 4 WFC3/IR MULTIAC IR-UVIS- F160W none none none none 1 N/A CUM FIX 16864( 2) - 22-Nov-2021 15:15:43 - [ 5] Visit: 02 Visit Requirements: ORIENT 180D TO 180D FROM 01; BETWEEN 01-JAN-2023:00:00:00 AND 01-APR-2023:00:00:00 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-4 WFC3/IR MULTIAC IR-UVIS-F F110W SAMP-SEQ=SPARS50, NSAMP=14 1 DEF POS TARG -5, 5 CUM IX (652.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 M-4 WFC3/IR MULTIAC IR-UVIS-F F110W SAMP-SEQ=SPARS50, NSAMP=14 1 DEF POS TARG -2.5, 2.5 CUM IX (652.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 M-4 WFC3/IR MULTIAC IR-UVIS-F F160W SAMP-SEQ=SPARS50, NSAMP=13 1 DEF POS TARG 0, 0 CUM IX (602.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 M-4 WFC3/IR MULTIAC IR-UVIS-F F160W SAMP-SEQ=SPARS50, NSAMP=13 1 DEF POS TARG -7.5, 7.5 CUM IX (602.938 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-4 1 WFC3/IR MULTIAC IR-UVIS- F110W none none none none 1 N/A CUM FIX M-4 2 WFC3/IR MULTIAC IR-UVIS- F110W none none none none 1 N/A CUM FIX M-4 3 WFC3/IR MULTIAC IR-UVIS- F160W none none none none 1 N/A CUM FIX M-4 4 WFC3/IR MULTIAC IR-UVIS- F160W none none none none 1 N/A CUM FIX 16864( 2) - 22-Nov-2021 15:15:43 - [ 6] Visit: 03 (OC F110W) Visit Requirements: SCHED 60%; ORIENT 309.2D TO 314.2 D; BETWEEN 01-JAN-2022:00:00:00 AND 30-APR-2022:00:00:00 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 NGC-5139B WFC3/IR MULTIAC IR F110W NSAMP=15, SAMP-SEQ=SPARS10 1 DEF CUM (142.946 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-5139B WFC3/IR MULTIAC IR F110W NSAMP=13, SAMP-SEQ=SPARS100 1 DEF CUM (1202.936 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC-5139B WFC3/IR MULTIAC IR F110W NSAMP=13, SAMP-SEQ=SPARS100 1 DEF POS TARG 26.5, 27.5 CUM (1202.936 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-5139B 1 WFC3/IR MULTIAC IR F110W none none none none 1 N/A CUM NGC-5139B 2 WFC3/IR MULTIAC IR F110W none none none none 1 N/A CUM NGC-5139B 3 WFC3/IR MULTIAC IR F110W none none none none 1 N/A CUM 16864( 2) - 22-Nov-2021 15:15:43 - [ 7] Visit: 04 (OC F160W) Visit Requirements: SCHED 60%; ORIENT 309.2D TO 314.2 D; AFTER 03 BY 3 D TO 100 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 NGC-5139B WFC3/IR MULTIAC IR F160W NSAMP=15, SAMP-SEQ=SPARS10 1 DEF CUM (142.946 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-5139B WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS100 1 DEF CUM (1202.936 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC-5139B WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS100 1 DEF POS TARG 26.5, 27.5 CUM (1202.936 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-5139B 1 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM NGC-5139B 2 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM NGC-5139B 3 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM 16864( 2) - 22-Nov-2021 15:15:43 - [ 8] Visit: 05 (47Tuc) Visit Requirements: BETWEEN 01-JAN-2022:00:00:00 AND 01-APR-2022:00:00:00 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 DARK WFC3/IR MULTIAC IR BLANK SAMP-SEQ=SPARS25, NSAMP=13 1 DEF CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 47TUC WFC3/IR MULTIAC IR-FIX F160W SAMP-SEQ=SPARS10, NSAMP=10 1 DEF CUM (92.941 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 DARK WFC3/IR MULTIAC IR BLANK SAMP-SEQ=SPARS50, NSAMP=15 1 DEF CUM (702.939 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 47TUC WFC3/IR MULTIAC IR-FIX F160W SAMP-SEQ=SPARS25, NSAMP=15 1 DEF CUM (352.94 S) Comments: Designed to just saturate V=20 stars. ------------------------------------------------------------------------------------------------------------------------------------ 5 DARK WFC3/IR MULTIAC IR BLANK SAMP-SEQ=SPARS50, NSAMP=15 1 DEF CUM (702.939 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 47TUC WFC3/IR MULTIAC IR-FIX F160W SAMP-SEQ=SPARS10, NSAMP=10 1 DEF CUM (92.941 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 47TUC WFC3/IR MULTIAC IR-FIX F160W SAMP-SEQ=SPARS25, NSAMP=13 1 DEF POS TARG 4, 4 CUM (302.938 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 | ------------------------------------------------------------------------------------------------------------------------------------ DARK 1 WFC3/IR MULTIAC IR BLANK none none none none 1 N/A CUM 47TUC 2 WFC3/IR MULTIAC IR-FIX F160W none none none none 1 N/A CUM DARK 3 WFC3/IR MULTIAC IR BLANK none none none none 1 N/A CUM 47TUC 4 WFC3/IR MULTIAC IR-FIX F160W none none none none 1 N/A CUM DARK 5 WFC3/IR MULTIAC IR BLANK none none none none 1 N/A CUM 16864( 2) - 22-Nov-2021 15:15:43 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 47TUC 6 WFC3/IR MULTIAC IR-FIX F160W none none none none 1 N/A CUM 47TUC 7 WFC3/IR MULTIAC IR-FIX F160W none none none none 1 N/A CUM 16864( 2) - 22-Nov-2021 15:15:43 - [ 10] Summary Form for Proposal 16864 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, IR-FIX, IR-UVIS-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=10, NSAMP=13, NSAMP=14, NSAMP=15, SAMP-SEQ=SPARS10, SAMP-SEQ=SPARS100, SAMP-SEQ=SPARS25, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 03 BY 3 D TO 100 D, BETWEEN 01-JAN-2022:00:00:00 AND 01-APR-2022:00:00:00, BETWEEN 01-JAN-2022:00:00:00 AND 30-APR-2022:00:00:00, BETWEEN 01-JAN-2023:00:00:00 AND 01-APR-2023:00:00:00, BETWEEN 20-AUG-2022:00:00:00 AND 15-SEP-2022:00:00:00, ORIENT 101.0D TO 101.0 D, ORIENT 180D TO 180D FROM 01, ORIENT 309.2D TO 314.2 D, POS TARG -2.5, 2.5, POS TARG -5, 5, POS TARG -7.5, 7.5, POS TARG 0, 0, POS TARG 26.5, 27.5, POS TARG 4, 4, SCHED 60% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements BLANK, F110W, F160W ------------------------------------------------------------------------------------------------------------------------------------ Target Names 47TUC, DARK, M-4, M-4-V1, NGC-5139B ------------------------------------------------------------------------------------------------------------------------------------