13376( 4) - 22-Jan-2014 12:46:25 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13376 Version: 4 Check-in Time: 22-Jan-2014 12:46:25 STScI Edit Number: 2 Title The Star Formation History of Leo P ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Kristen McQuinn University of Minnesota - Twin Cities Y CoI: Dr. Evan D. Skillman University of Minnesota - Twin Cities N CoI: Dr. John M. Cannon Macalester College N CoI: Prof. Riccardo Giovanelli Cornell University N CoI: Ms. Elizabeth Adams Cornell University N CoI: Prof. John J. Salzer Indiana University System N CoI: Dr. Katherine Rhode Indiana University System N CoI: Ms. Danielle Berg University of Minnesota - Twin Cities N CoI: Dr. Leo Girardi Osservatorio Astronomico di Padova N CoI: Prof. Martha Haynes Cornell University N CoI: Dr. Andrew Dolphin Raytheon Company N ------------------------------------------------------------------------------------ Abstract The nearby (D = 1.7+/-0.3 Mpc), very low luminosity (M_V = -9.3+/-0.4mag), gas-rich star forming galaxy Leo P was discovered by its HI 21cm emission in the Arecibo ALFALFA survey. Follow-up optical spectroscopy of its single HII region revealed an oxygen abundance of 12+log(O/H)=7.16+/-0.04, making it the lowest metallicity star forming galaxy in the Local Volume (D < 5 Mpc) and commensurate with the metallicities of emission line galaxies I Zw 18 and DDO 68. Thus, Leo P presents us with a unique opportunity to understand the evolution of extremely metal deficient (XMD) galaxies. Specifically, an HST color magnitude diagram which reaches below the red clump stars will allow us to reconstruct the lifetime star formation history with reasonable time resolution. The star formation history will answer two vital questions: (1) Did Leo P experience suppressed star formation during its early evolution like another isolated dwarf galaxy Leo A? and (2) What fraction of all newly created metals has Leo P been able to retain during its lifetime? ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this proposal is to reconstruct and interpret the star formation history (SFH) and chemical enrichment history of the newly discovered XMD dwarf galaxy Leo~P from a deep (I~27; V~28) color-magnitude diagram (CMD). Orbit allocation = 17 orbits. Most visits span 2-orbits with the ACS; each orbit is split between one F475W and one F814W exposure (with no CR-splits). Small ditherings are performed between exposures in order to remove hot pixels and to smooth the detector response. We don't intend to cover the interchip gap. Ditherings are performed using POS-TARG, and following the basic UDF dither pattern, shifted around by 13376( 4) - 22-Jan-2014 12:46:25 - [ 2] 2-3 pix. The observations will complete a total of 4 uniquely positioned UDF dither patterns plus an additional set of F475W and F814W images with a POS-TARG offset of 0.05, 0.05. The first visit is requested within a given range of orientations. This range has been chosen both to minimize the impact of a bright foreground star on the photometry of the galaxy and to maximize the areal coverage of both the main star-forming body and stellar halo of the galaxy. Subsequent visits are requested to be obtained with the same ORIENT as the first visit in order to maximize the sky area covered at full depth. We request the visits to be executed sequentially within a maximum time span of 3 days. This will ensure optimal sampling of the light curves of short period variable stars such as RR Lyrae, which will provide an independent constraint on the SFH of the galaxy, the main science goal of our progam. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 13376( 4) - 22-Jan-2014 12:46:25 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LEOP GALAXY, AMORPHOUS RA=10H21M48.0427S, J2000 V = 16.9 +/- 0.1 IRREGULAR DEC=+18D05'36.07" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13376( 4) - 22-Jan-2014 12:46:25 - [ 4] Visit: 01 Visit Requirements: ORIENT 80D TO 95 D; ORIENT 240D TO 270 D; SEQ 01, 02, 03, 04, 05, 06, 07, 08 WITHIN 3 D On Hold Comments: Additional Comments: We request a range of orientations in this first visit and the same orientation in the subsequent visits. Visits are also requested to be executed sequentially within a 3 day period. 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1465 S GS ACQ SCENARIO BASE1B3 see below (1522 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 935 S see below (992 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 935 S POS TARG 0.148, 0.086 see below (1103 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.148, 0.086 see below (1603 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 1522.0 S LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 992.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1103.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1603.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 5] Visit: 02 Visit Requirements: SAME ORIENT AS 01; AFTER 01 BY 4 H TO 3 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.222, 0.240; (1435 S) GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.222, 0.240 see below (1079 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.074, 0.154 see below (1118 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.074, 0.154 see below (1588 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 N/A LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1079.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1118.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1588.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 6] Visit: 03 Visit Requirements: SAME ORIENT AS 01; AFTER 02 BY 4 H TO 3 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.085, 0.105; (1435 S) GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.085, 0.105 see below (1079 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.233, 0.191 see below (1118 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.233, 0.191 see below (1588 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 N/A LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1079.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1118.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1588.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 7] Visit: 04 Visit Requirements: SAME ORIENT AS 01; AFTER 03 BY 4 H TO 3 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.307, 0.345; (1435 S) GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.307, 0.345 see below (1079 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.159, 0.259 see below (1118 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.159, 0.259 see below (1588 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 N/A LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1079.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1118.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1588.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 8] Visit: 05 Visit Requirements: SAME ORIENT AS 01; AFTER 04 BY 4 H TO 3 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.085, 0.0; GS (1435 S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.085, 0.0 see below (1079 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.233, 0.086 see below (1118 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.233, 0.086 see below (1588 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 N/A LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1079.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1118.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1588.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 9] Visit: 06 Visit Requirements: SAME ORIENT AS 01; AFTER 05 BY 4 H TO 3 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.307, 0.240; (1435 S) GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.307, 0.240 see below (1079 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.159, 0.154 see below (1118 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.159, 0.154 see below (1588 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 N/A LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1079.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1118.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1588.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 10] Visit: 07 Visit Requirements: SAME ORIENT AS 01; AFTER 06 BY 4 H TO 3 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.0, 0.105; GS (1435 S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.0, 0.105 see below (1079 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.148, 0.191 see below (1118 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.148, 0.191 see below (1588 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 N/A LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1079.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1118.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1588.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 11] Visit: 08 Visit Requirements: SAME ORIENT AS 01; AFTER 07 BY 4 H TO 3 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 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.222, 0.345; (1435 S) GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.222, 0.345 see below (1079 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.074, 0.259 see below (1118 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.074, 0.259 see below (1588 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 LEOP ACS/WFC ACCUM WFCENTER F814W 1 965 S POS TARG 0.05, 0.05 see below (1022 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 LEOP ACS/WFC ACCUM WFCENTER F475W 1 1435 S POS TARG 0.05, 0.05 see below (1645 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEOP 1 ACS/WFC ACCUM WFCENTER F475W none none none none 1 N/A LEOP 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1079.0 S LEOP 3 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1118.0 S LEOP 4 ACS/WFC ACCUM WFCENTER F475W none none none none 2 1588.0 S LEOP 5 ACS/WFC ACCUM WFCENTER F814W none none none none 3 1022.0 S LEOP 6 ACS/WFC ACCUM WFCENTER F475W none none none none 3 1645.0 S 13376( 4) - 22-Jan-2014 12:46:25 - [ 12] Summary Form for Proposal 13376 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 4 H TO 3 D, AFTER 02 BY 4 H TO 3 D, AFTER 03 BY 4 H TO 3 D, AFTER 04 BY 4 H TO 3 D, AFTER 05 BY 4 H TO 3 D, AFTER 06 BY 4 H TO 3 D, AFTER 07 BY 4 H TO 3 D, GS ACQ SCENARIO BASE1B3, ORIENT 240D TO 270 D, ORIENT 80D TO 95 D, POS TARG 0.0, 0.105, POS TARG 0.05, 0.05, POS TARG 0.074, 0.154, POS TARG 0.074, 0.259, POS TARG 0.085, 0.0, POS TARG 0.085, 0.105, POS TARG 0.148, 0.086, POS TARG 0.148, 0.191, POS TARG 0.159, 0.154, POS TARG 0.159, 0.259, POS TARG 0.222, 0.240, POS TARG 0.222, 0.345, POS TARG 0.233, 0.086, POS TARG 0.233, 0.191, POS TARG 0.307, 0.240, POS TARG 0.307, 0.345, SAME ORIENT AS 01, SEQ 01, 02, 03, 04, 05, 06, 07, 08 WITHIN 3 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names LEOP ------------------------------------------------------------------------------------------------------------------------------------