14155( 2) - 23-Jul-2015 15:25:30 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14155 Version: 2 Check-in Time: 23-Jul-2015 15:25:30 STScI Edit Number: 0 Title Using Stellar Evolution as a Clock to Watch the Dynamical Evolution of a Globular Cluster ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Jason S. Kalirai Space Telescope Science Institute Y CoI: Dr. Jeremy Heyl University of British Columbia N CoI: Dr. Harvey B. Richer University of British Columbia N CoI: Dr. Brad M. Hansen University of California - Los Angeles N CoI: Dr. Laura L. Watkins Space Telescope Science Institute N CoI: Dr. Paola Marigo Universita degli Studi di Padova N CoI: Dr. Pier-Emmanuel Tremblay Space Telescope Science Institute N CoI: Dr. Jeffrey Cummings The Johns Hopkins University N CoI: Dr. Matteo Correnti Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract We propose a 5 orbit HST program to acquire UV imaging at the center of the massive globular cluster NGC 362, in order to directly measure the rate of diffusion of stars through its core. This measurement will overcome a major observational barrier; that the dynamical time scale for two-body relaxation in the core of a globular cluster is typically much shorter than the age of the population, and so mass segregation in the cluster occured billions of years ago. Our novel technique aims to resolve this dynamical evolution by using the full power of WFC3's exquisite UV sensitivity at <0.3 microns combined with its high spatial resolution. We will uncover ~1000 newly formed stellar remnants - white dwarfs - in the center of the globular cluster and track how their spatial distribution changes as they get "older" on the cooling sequence. Having just experienced a significant episode of mass loss, the youngest white dwarfs with ages <10s of Myr will still be moving slowly like their 0.8 Msun progenitors, whereas the "older" white dwarfs that have been cooling for >100s of Myr will be fully relaxed. To "watch" this dynamical evolution and directly measure the diffusion coefficient, we have selected the very populous globular cluster NGC 362. The cluster is nearby with low reddening, has moderate concentration, and has a theoretical expected relaxation timescale of 60 Myr in its core, perfect to split the young and old white dwarfs that we can observe with Hubble. ------------------------------------------------------------------------------------ Observations Description ------------------------ We are obtaining UV imaging with WFC3/UVIS in F225W and F275W of the core of NGC 362, and parallel ACS imaging in F435W and F555W of an outer field. The goal of the program is to measure the spatial distribution of newly formed white dwarfs and compare them to "older" remnants. Although both populations have the same mass, the newly formed remnants were much heavier less than one relaxation time ago. The difference will constrain the diffusion constant due to dynamical relaxation. For the WFC3/UVIS observations, we place the core of the globular cluster near the center of the WFC3 field and obtain 1 short and 4 14155( 2) - 23-Jul-2015 15:25:30 - [ 2] long (dithered) exposures in each orbit. Post flash has been added to ensure 12 e- in each exposure to mitigate CTE. The parallel field will image a part of the cluster at larger radii for additional constraints on the spatial distribution of cool white dwarfs. All observations require a standard dither, implemented through POSTARGs. We have added an ORIENT constraint to ensure that the field nicely overlaps the archival F275W observations that will be coadded with this data. ------------------------------------------------------------------------------------ 14155( 2) - 23-Jul-2015 15:25:30 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-362 STELLAR CLUSTER, RA=01H03M14.2600S, J2000 V = 6.58 GLOBULAR CLUSTER DEC=-70D50'55.60" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 14155( 2) - 23-Jul-2015 15:25:30 - [ 4] Visit: 01 Visit Requirements: ORIENT 180D TO 220 D; ORIENT 0D TO 40 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-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 30 S (30 POS TARG 0, -15; PAR 3 S ER S) WITH 1-2 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 650 S (650 POS TARG 0, -15 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC-362 ACS/WFC ACCUM WFC F435W 1 400 S (400 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 680 S (680 POS TARG 0.158, -15.070; S ER S) PAR 5 WITH 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC-362 ACS/WFC ACCUM WFC F435W 1 620 S (620 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG 0.099, -15.165; S ER S) PAR 7 WITH 6 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC-362 ACS/WFC ACCUM WFC F435W 1 650 S (650 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 580 S (580 POS TARG -0.060, S ER S) -15.298; PAR 9 WITH 8 ------------------------------------------------------------------------------------------------------------------------------------ 9 NGC-362 ACS/WFC ACCUM WFC F435W 1 450 S (450 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 30 S (30 POS TARG -0.120, S ER S) -15.358; PAR 12 WITH 10-11 ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 650 S (650 POS TARG -0.120, -15.358 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC-362 ACS/WFC ACCUM WFC F435W 1 790 S (790 S) ------------------------------------------------------------------------------------------------------------------------------------ 13 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG -0.6, -15.50; S ER S) PAR 14 WITH 13 ------------------------------------------------------------------------------------------------------------------------------------ 14 NGC-362 ACS/WFC ACCUM WFC F435W 1 670 S (670 S) 14155( 2) - 23-Jul-2015 15:25:30 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------------------------ 15 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG -1.1, -15.71; S ER S) PAR 16 WITH 15 ------------------------------------------------------------------------------------------------------------------------------------ 16 NGC-362 ACS/WFC ACCUM WFC F435W 1 680 S (680 S) ------------------------------------------------------------------------------------------------------------------------------------ 17 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG -1.55, -17.21; S ER S) PAR 18 WITH 17 ------------------------------------------------------------------------------------------------------------------------------------ 18 NGC-362 ACS/WFC ACCUM WFC F435W 1 580 S (580 S) ------------------------------------------------------------------------------------------------------------------------------------ 19 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 30 S (30 POS TARG 0, -17.21; PAR S ER S) 21 WITH 19-20 ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 650 S (650 POS TARG 0, -17.21 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 21 NGC-362 ACS/WFC ACCUM WFC F435W 1 790 S (790 S) ------------------------------------------------------------------------------------------------------------------------------------ 22 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG 0.158, -17.28; S ER S) PAR 23 WITH 22 ------------------------------------------------------------------------------------------------------------------------------------ 23 NGC-362 ACS/WFC ACCUM WFC F435W 1 670 S (670 S) ------------------------------------------------------------------------------------------------------------------------------------ 24 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG 0.099, -17.375; S ER S) PAR 25 WITH 24 ------------------------------------------------------------------------------------------------------------------------------------ 25 NGC-362 ACS/WFC ACCUM WFC F435W 1 680 S (680 S) ------------------------------------------------------------------------------------------------------------------------------------ 26 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG -0.060, S ER S) -17.508; PAR 27 WITH 26 ------------------------------------------------------------------------------------------------------------------------------------ 27 NGC-362 ACS/WFC ACCUM WFC F435W 1 580 S (580 S) ------------------------------------------------------------------------------------------------------------------------------------ 28 NGC-362 WFC3/UVI ACCUM UVIS-CENT F275W FLASH=12 1 30 S (30 POS TARG 0, -15; PAR 30 S ER S) WITH 28-29 ------------------------------------------------------------------------------------------------------------------------------------ 29 NGC-362 WFC3/UVI ACCUM UVIS-CENT F275W FLASH=12 1 650 S (650 POS TARG 0, -15 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 14155( 2) - 23-Jul-2015 15:25:30 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC-362 ACS/WFC ACCUM WFC F555W 1 770 S (770 S) ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 680 S (680 POS TARG -0.7, -17.10; S ER S) PAR 32 WITH 31 ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC-362 ACS/WFC ACCUM WFC F555W 1 670 S (670 S) ------------------------------------------------------------------------------------------------------------------------------------ 33 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 700 S (700 POS TARG -0.4, -16.80; S ER S) PAR 34 WITH 33 ------------------------------------------------------------------------------------------------------------------------------------ 34 NGC-362 ACS/WFC ACCUM WFC F555W 1 680 S (680 S) ------------------------------------------------------------------------------------------------------------------------------------ 35 NGC-362 WFC3/UVI ACCUM UVIS-CENT F225W FLASH=12 1 680 S (680 POS TARG -0.1, -16.50; S ER S) PAR 36 WITH 35 ------------------------------------------------------------------------------------------------------------------------------------ 36 NGC-362 ACS/WFC ACCUM WFC F555W 1 560 S (560 S) ------------------------------------------------------------------------------------------------------------------------------------ 37 NGC-362 WFC3/UVI ACCUM UVIS-CENT F275W FLASH=12 1 30 S (30 POS TARG 0.158, -16.303; S ER S) PAR 39 WITH 37-38 ------------------------------------------------------------------------------------------------------------------------------------ 38 NGC-362 WFC3/UVI ACCUM UVIS-CENT F275W FLASH=12 1 650 S (650 POS TARG 0.158, -16.303 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 39 NGC-362 ACS/WFC ACCUM WFC F555W 1 790 S (790 S) ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC-362 WFC3/UVI ACCUM UVIS-CENT F275W FLASH=12 1 700 S (700 POS TARG 0.099, -16.398; S ER S) PAR 41 WITH 40 ------------------------------------------------------------------------------------------------------------------------------------ 41 NGC-362 ACS/WFC ACCUM WFC F555W 1 670 S (670 S) ------------------------------------------------------------------------------------------------------------------------------------ 42 NGC-362 WFC3/UVI ACCUM UVIS-CENT F275W FLASH=12 1 700 S (700 POS TARG -0.060, S ER S) -16.531; PAR 43 WITH 42 ------------------------------------------------------------------------------------------------------------------------------------ 43 NGC-362 ACS/WFC ACCUM WFC F555W 1 680 S (680 S) ------------------------------------------------------------------------------------------------------------------------------------ 44 NGC-362 WFC3/UVI ACCUM UVIS-CENT F275W FLASH=12 1 680 S (680 POS TARG 0.158, -15.070; S ER S) PAR 45 WITH 44 ------------------------------------------------------------------------------------------------------------------------------------ 45 NGC-362 ACS/WFC ACCUM WFC F555W 1 560 S (560 S) 14155( 2) - 23-Jul-2015 15:25:30 - [ 7] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------------------------ 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-362 1 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 1 N/A S TER NGC-362 2 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 1 N/A S TER NGC-362 3 ACS/WFC ACCUM WFC F435W none none none none 1 N/A NGC-362 4 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 1 N/A S TER NGC-362 5 ACS/WFC ACCUM WFC F435W none none none none 1 N/A NGC-362 6 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 1 N/A S TER NGC-362 7 ACS/WFC ACCUM WFC F435W none none none none 1 N/A NGC-362 8 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 1 N/A S TER NGC-362 9 ACS/WFC ACCUM WFC F435W none none none none 1 N/A NGC-362 10 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 2 N/A S TER NGC-362 11 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 2 N/A S TER NGC-362 12 ACS/WFC ACCUM WFC F435W none none none none 2 N/A NGC-362 13 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 2 N/A S TER NGC-362 14 ACS/WFC ACCUM WFC F435W none none none none 2 N/A NGC-362 15 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 2 N/A S TER NGC-362 16 ACS/WFC ACCUM WFC F435W none none none none 2 N/A NGC-362 17 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 2 N/A S TER NGC-362 18 ACS/WFC ACCUM WFC F435W none none none none 2 N/A NGC-362 19 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 3 N/A S TER NGC-362 20 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 3 N/A S TER NGC-362 21 ACS/WFC ACCUM WFC F435W none none none none 3 N/A NGC-362 22 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 3 N/A S TER NGC-362 23 ACS/WFC ACCUM WFC F435W none none none none 3 N/A NGC-362 24 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 3 N/A S TER NGC-362 25 ACS/WFC ACCUM WFC F435W none none none none 3 N/A 14155( 2) - 23-Jul-2015 15:25:30 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-362 26 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 3 N/A S TER NGC-362 27 ACS/WFC ACCUM WFC F435W none none none none 3 N/A NGC-362 28 WFC3/UVI ACCUM UVIS-CEN F275W none none none none 4 N/A S TER NGC-362 29 WFC3/UVI ACCUM UVIS-CEN F275W none none none none 4 N/A S TER NGC-362 30 ACS/WFC ACCUM WFC F555W none none none none 4 N/A NGC-362 31 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 4 N/A S TER NGC-362 32 ACS/WFC ACCUM WFC F555W none none none none 4 N/A NGC-362 33 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 4 N/A S TER NGC-362 34 ACS/WFC ACCUM WFC F555W none none none none 4 N/A NGC-362 35 WFC3/UVI ACCUM UVIS-CEN F225W none none none none 4 N/A S TER NGC-362 36 ACS/WFC ACCUM WFC F555W none none none none 4 N/A NGC-362 37 WFC3/UVI ACCUM UVIS-CEN F275W none none none none 5 N/A S TER NGC-362 38 WFC3/UVI ACCUM UVIS-CEN F275W none none none none 5 N/A S TER NGC-362 39 ACS/WFC ACCUM WFC F555W none none none none 5 N/A NGC-362 40 WFC3/UVI ACCUM UVIS-CEN F275W none none none none 5 N/A S TER NGC-362 41 ACS/WFC ACCUM WFC F555W none none none none 5 N/A NGC-362 42 WFC3/UVI ACCUM UVIS-CEN F275W none none none none 5 N/A S TER NGC-362 43 ACS/WFC ACCUM WFC F555W none none none none 5 N/A NGC-362 44 WFC3/UVI ACCUM UVIS-CEN F275W none none none none 5 N/A S TER NGC-362 45 ACS/WFC ACCUM WFC F555W none none none none 5 N/A 14155( 2) - 23-Jul-2015 15:25:30 - [ 9] Summary Form for Proposal 14155 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-CENTER, WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=12 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 0D TO 40 D, ORIENT 180D TO 220 D, PAR 12 WITH 10-11, PAR 14 WITH 13, PAR 16 WITH 15, PAR 18 WITH 17, PAR 21 WITH 19-20, PAR 23 WITH 22, PAR 25 WITH 24, PAR 27 WITH 26, PAR 3 WITH 1-2, PAR 30 WITH 28-29, PAR 32 WITH 31, PAR 34 WITH 33, PAR 36 WITH 35, PAR 39 WITH 37-38, PAR 41 WITH 40, PAR 43 WITH 42, PAR 45 WITH 44, PAR 5 WITH 4, PAR 7 WITH 6, PAR 9 WITH 8, POS TARG -0.060, -15.298, POS TARG -0.060, -16.531, POS TARG -0.060, -17.508, POS TARG -0.1, -16.50, POS TARG -0.120, -15.358, POS TARG -0.4, -16.80, POS TARG -0.6, -15.50, POS TARG -0.7, -17.10, POS TARG -1.1, -15.71, POS TARG -1.55, -17.21, POS TARG 0, -15, POS TARG 0, -17.21, POS TARG 0.099, -15.165, POS TARG 0.099, -16.398, POS TARG 0.099, -17.375, POS TARG 0.158, -15.070, POS TARG 0.158, -16.303, POS TARG 0.158, -17.28 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F225W, F275W, F435W, F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC-362 ------------------------------------------------------------------------------------------------------------------------------------