15881( 3) - 21-Feb-2020 14:20:10 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15881 Version: 3 Check-in Time: 21-Feb-2020 14:20:10 STScI Edit Number: 1 Title Ultra-Deep HST/COS Spectroscopy of Extremely Metal-Poor Galaxies ------------------------------------------------------------------------------------ Type Cycle GO 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Daniel P. Stark University of Arizona Y CoI: Peter Senchyna University of Arizona N CoI: Dr. Jacopo Chevallard CNRS, Institut d'Astrophysique de Paris N CoI: Dr. Stephane Charlot CNRS, Institut d'Astrophysique de Paris N CoI: Prof. Tucker Jones University of California - Davis N ------------------------------------------------------------------------------------ Abstract The first glimpse of the spectra of z~7-10 galaxies has revealed intense nebular emission that has proven challenging to interpret owing to shortcomings in our understanding of low metallicity stellar populations. Recent work with HST/COS in the local universe has provided a way forward, characterizing the UV spectra that are common in metal poor galaxies. Attention to date has focused on the strongest CIV emitting galaxies found locally, as these appear most similar to the few detections known at z>6. But it has recently become clear that the majority of metal poor galaxies exhibit much weaker CIV. Nothing is known about the nature of the massive stars in these systems, resulting in an extremely biased view of the range of radiation fields powered by low metallicity stars in metal poor galaxies. Here we propose to combat this problem by providing the first study of the massive stars in the dominant population of metal poor galaxies in the local universe. Via deep (5 orbit) COS/G160M spectra of two of the z<0.02 metal poor galaxies with weak CIV emission, we will deliver quantitative constraints on the metallicity of massive stars through measurement of photospheric absorption lines and test stellar wind prescriptions in the poorly calibrated low metallicity regime. Using new spectral tools, we will test whether existing population synthesis models can simultaneously reproduce the metallicity and radiation field, providing a powerful stress test for models. If this UV database is not completed soon, the interpretation of reionization era galaxy spectra will be jeopardized throughout the JWST era. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our program will obtain ultra-deep medium-resolution FUV COS spectroscopy for two highly star-forming extremely metal-poor galaxies identified as producing anomalously weak nebular C IV emission. The target galaxies are compact, have high-precision coordinates confirmed in SDSS, and have been previously observed with lower-resolution COS spectroscopy. In order to make the program as flexible as possible in scheduling, we have broken the 5 orbits devoted to each galaxy into 3 separate visits. As in previous COS programs targeting similar galaxies, we will perform ACQ/IMAGE exposures to center the galaxies in the COS aperture. Then, each orbit will be devoted to integration at a single FP-POS setting, with buffer readout and grating shift occuring during occultation. Since readout occurs during occultation, we set the BUFFER-TIME to the exposure 15881( 3) - 21-Feb-2020 14:20:10 - [ 2] time to ensure the entire buffer is read. All observations will be conducted with G160M/1533, which gives simultaneous coverage of key stellar wind lines and photospheric features in the range 1350-1700 Angstroms yielding constraints on stellar wind strengths and stellar Fe abundance. In five orbits per object, we will achieve S/N per resolution element >4, providing confident measurement of these features and a comprehensive picture of the massive stellar populations in the target systems. ------------------------------------------------------------------------------------ 15881( 3) - 21-Feb-2020 14:20:10 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ082555. GALAXY, STAR FORMING RA=08H25M55.5207S +/- 0.1", J2000 V = 18.5 52+353231.9 REGION DEC=+35D32'31.96" +/- 0.1" Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ120202. GALAXY, STAR FORMING RA=12H02M2.4925S +/- 0.1", J2000 V = 19.5 49+541551.0 REGION DEC=+54D15'51.05" +/- 0.1" Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 15881( 3) - 21-Feb-2020 14:20:10 - [ 4] 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 SDSSJ082555 COS/NUV ACQ/IMA PSA MIRRORA 1 21 S (21 .52+353231. GE S) 9 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ082555 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2400, FLASH=YES, 1 2400 S .52+353231. G FP-POS=1 (2400 S) 9 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ082555 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2834, FLASH=YES, 1 2800 S .52+353231. G FP-POS=2 see below 9 (2834 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ082555.52+3532 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 31.9 GE SDSSJ082555.52+3532 2 COS/FUV TIME-TA PSA G160M 1533 none none none none 1 N/A 31.9 G SDSSJ082555.52+3532 3 COS/FUV TIME-TA PSA G160M 1533 none none none none 2 2834.0 S 31.9 G 15881( 3) - 21-Feb-2020 14:20:10 - [ 5] 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 SDSSJ082555 COS/NUV ACQ/IMA PSA MIRRORA 1 21 S (21 .52+353231. GE S) 9 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ082555 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2400, FLASH=YES, 1 2400 S .52+353231. G FP-POS=3 (2400 S) 9 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ082555 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2834, FLASH=YES, 1 2800 S .52+353231. G FP-POS=4 see below 9 (2834 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ082555.52+3532 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 31.9 GE SDSSJ082555.52+3532 2 COS/FUV TIME-TA PSA G160M 1533 none none none none 1 N/A 31.9 G SDSSJ082555.52+3532 3 COS/FUV TIME-TA PSA G160M 1533 none none none none 2 2834.0 S 31.9 G 15881( 3) - 21-Feb-2020 14:20:10 - [ 6] 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 SDSSJ082555 COS/NUV ACQ/IMA PSA MIRRORA 1 21 S (21 .52+353231. GE S) 9 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ082555 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2400, FLASH=YES, 1 2400 S .52+353231. G FP-POS=1 (2400 S) 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ082555.52+3532 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 31.9 GE SDSSJ082555.52+3532 2 COS/FUV TIME-TA PSA G160M 1533 none none none none 1 N/A 31.9 G 15881( 3) - 21-Feb-2020 14:20:10 - [ 7] 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 SDSSJ120202 COS/NUV ACQ/IMA PSA MIRRORA 1 27 S (27 .49+541551. GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ120202 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2521, FLASH=YES, 1 2400 S .49+541551. G FP-POS=1 see below 0 (2521 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ120202 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2967, FLASH=YES, 1 2800 S .49+541551. G FP-POS=2 see below 0 (2967 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ120202.49+5415 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 51.0 GE SDSSJ120202.49+5415 2 COS/FUV TIME-TA PSA G160M 1533 none none none none 1 2521.0 S 51.0 G SDSSJ120202.49+5415 3 COS/FUV TIME-TA PSA G160M 1533 none none none none 2 2967.0 S 51.0 G 15881( 3) - 21-Feb-2020 14:20:10 - [ 8] 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 SDSSJ120202 COS/NUV ACQ/IMA PSA MIRRORA 1 27 S (27 .49+541551. GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ120202 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2521, FLASH=YES, 1 2400 S .49+541551. G FP-POS=3 see below 0 (2521 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ120202 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2967, FLASH=YES, 1 2800 S .49+541551. G FP-POS=4 see below 0 (2967 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ120202.49+5415 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 51.0 GE SDSSJ120202.49+5415 2 COS/FUV TIME-TA PSA G160M 1533 none none none none 1 2521.0 S 51.0 G SDSSJ120202.49+5415 3 COS/FUV TIME-TA PSA G160M 1533 none none none none 2 2967.0 S 51.0 G 15881( 3) - 21-Feb-2020 14:20:10 - [ 9] Visit: 06 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 SDSSJ120202 COS/NUV ACQ/IMA PSA MIRRORA 1 27 S (27 .49+541551. GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ120202 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2521, FLASH=YES, 1 2400 S .49+541551. G FP-POS=1 see below 0 (2521 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ120202.49+5415 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 51.0 GE SDSSJ120202.49+5415 2 COS/FUV TIME-TA PSA G160M 1533 none none none none 1 2521.0 S 51.0 G 15881( 3) - 21-Feb-2020 14:20:10 - [ 10] Visit: 53 Visit Requirements: On Hold Comments: Additional Comments: Repeat of failed 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 SDSSJ082555 COS/NUV ACQ/IMA PSA MIRRORA 1 21 S (21 .52+353231. GE S) 9 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ082555 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=2400, FLASH=YES, 1 2400 S .52+353231. G FP-POS=1 (2400 S) 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ082555.52+3532 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 31.9 GE SDSSJ082555.52+3532 2 COS/FUV TIME-TA PSA G160M 1533 none none none none 1 N/A 31.9 G 15881( 3) - 21-Feb-2020 14:20:10 - [ 11] Summary Form for Proposal 15881 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=2400, BUFFER-TIME=2521, BUFFER-TIME=2834, BUFFER-TIME=2967, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names SDSSJ082555.52+353231.9, SDSSJ120202.49+541551.0 ------------------------------------------------------------------------------------------------------------------------------------