15471( 5) - 05-Dec-2018 18:08:03 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15471 Version: 5 Check-in Time: 05-Dec-2018 18:08:03 STScI Edit Number: 1 Title The Extreme Starbursts that Re-ionized the Universe: Definitive Spectroscopic Detections of Escaping Lyman Limit Photons ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Matthew A. Malkan University of California - Los Angeles Y ------------------------------------------------------------------------------------ Abstract We recently made a new broadband photometric search for galaxies in the SDSS DR14 having i-band excesses, due to extremely strong [OIII] emission lines (rest EW([OIII])>900Ang), at z~0.50. This identified a rapidly evolving population of "green pea" galaxies, which appear to be the likely sources of most of the ionizing photons escaping into the IGM. These spectroscopically confirmed extreme starbursts in metal-poor dwarf galaxies are the kind of 'young' galaxies which are thought to have re-ionized the universe. Their ISM is very highly ionized, and practically un-reddened. Their higher redshifts push their Lyman limits into a far more sensitive wavelength region of the HST/COS spectrograph than has been utilized on previous searches for ionizing photons leaking from lower-redshift galaxies. We propose FUV spectroscopy of two representatives of this newly studied galaxy population with very bright [OIII]. They are very compact intense starbursts (sSFR~10**-8 /year), with no trace of an AGN. Their extremely blue stellar continuum is well detected in the NUV and FUV by GALEX.Their continuum brightness at an observed wavelength of 1400Ang (just redward of the Lyman limit) guarantees us of DETECTING their escaping Lyman limit fluxes at the 3-sigma level, even if the relative ionizing escape fraction is as low as 3.7%. We will also simultaneously measure their Lyman-alpha emission line profiles, to search for outflows and/or closely spaced double peaked emission that may be correlated with Lyman continuum leakage. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will obtain FUV spectroscopy of two extreme emission-line galaxies. Their extremely high specific star formation rates, and high-ionization gas make them prime candidates for detectable 'leakage' of ionizing photons. Their high redsfhits (z~0.5) shift their continuum shortward of the Lyman limit into the sensitive region of the COS spectrograph. We will therefore observe each of the two targets spectroscopically in the same short-wavelength setting for 3 full orbits apiece. ------------------------------------------------------------------------------------ 15471( 5) - 05-Dec-2018 18:08:03 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSS-J090334 GALAXY, DWARF COMPACT, RA=09H03M34.5900S +/- 0.35", J2000 V = 19.9 +/- 0.05 .59+174717.7 STARBURST DEC=+17D47'17.74" +/- 0.35" Reference Frame: ICRS Extended: YES Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSS-J020747 GALAXY, DWARF COMPACT, RA=02H07M47.9856S +/- 0.35", J2000 V = 19.95 +/- .05 .98+004735.4 STARBURST DEC=+00D47'35.45" +/- 0.35" Reference Frame: ICRS Extended: YES Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 15471( 5) - 05-Dec-2018 18:08:03 - [ 3] Visit: 01 (First Visit, First Target Galaxy) Visit Requirements: On Hold Comments: Additional Comments: SDSS090334.59 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 SDSS-J09033 COS/NUV ACQ/IMA PSA MIRRORA 1 60 S (60 4.59+174717 GE S) .7 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSS-J09033 COS/FUV TIME-TA PSA G140L 1280 FP-POS=1, FLASH=YES, 1 2440 S 4.59+174717 G BUFFER-TIME=20000 (2440 S) .7 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSS-J09033 COS/FUV TIME-TA PSA G140L 1280 FP-POS=2, FLASH=YES, 1 2920 S 4.59+174717 G BUFFER-TIME=20000 (2920 S) .7 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSS-J09033 COS/FUV TIME-TA PSA G140L 1280 FP-POS=3, FLASH=YES, 1 1400 S 4.59+174717 G BUFFER-TIME=20000 (1400 S) .7 ------------------------------------------------------------------------------------------------------------------------------------ 5 SDSS-J09033 COS/FUV TIME-TA PSA G140L 1280 FP-POS=4, FLASH=YES, 1 1400 S 4.59+174717 G BUFFER-TIME=20000 (1400 S) .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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSS-J090334.59+174 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 717.7 GE SDSS-J090334.59+174 2 COS/FUV TIME-TA PSA G140L 1280 none none none none 1 N/A 717.7 G SDSS-J090334.59+174 3 COS/FUV TIME-TA PSA G140L 1280 none none none none 2 N/A 717.7 G SDSS-J090334.59+174 4 COS/FUV TIME-TA PSA G140L 1280 none none none none 3 N/A 717.7 G SDSS-J090334.59+174 5 COS/FUV TIME-TA PSA G140L 1280 none none none none 3 N/A 717.7 G 15471( 5) - 05-Dec-2018 18:08:03 - [ 4] Visit: 02 (Second Visit, Second Target) Visit Requirements: On Hold Comments: Additional Comments: [OIII] galaxy 020747.98 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 SDSS-J02074 COS/NUV ACQ/IMA PSA MIRRORA 1 55 S (55 7.98+004735 GE S) .4 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSS-J02074 COS/FUV TIME-TA PSA G140L 1280 FP-POS=1, FLASH=YES, 1 2440 S 7.98+004735 G BUFFER-TIME=20000 (2440 S) .4 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSS-J02074 COS/FUV TIME-TA PSA G140L 1280 FP-POS=2, FLASH=YES, 1 2900 S 7.98+004735 G BUFFER-TIME=20000 (2900 S) .4 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSS-J02074 COS/FUV TIME-TA PSA G140L 1280 FP-POS=3, FLASH=YES, 1 1400 S 7.98+004735 G BUFFER-TIME=20000 (1400 S) .4 ------------------------------------------------------------------------------------------------------------------------------------ 5 SDSS-J02074 COS/FUV TIME-TA PSA G140L 1280 FP-POS=4, FLASH=YES, 1 1400 S 7.98+004735 G BUFFER-TIME=20000 (1400 S) .4 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSS-J020747.98+004 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 735.4 GE SDSS-J020747.98+004 2 COS/FUV TIME-TA PSA G140L 1280 none none none none 1 N/A 735.4 G SDSS-J020747.98+004 3 COS/FUV TIME-TA PSA G140L 1280 none none none none 2 N/A 735.4 G SDSS-J020747.98+004 4 COS/FUV TIME-TA PSA G140L 1280 none none none none 3 N/A 735.4 G SDSS-J020747.98+004 5 COS/FUV TIME-TA PSA G140L 1280 none none none none 3 N/A 735.4 G 15471( 5) - 05-Dec-2018 18:08:03 - [ 5] Summary Form for Proposal 15471 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=20000, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names SDSS-J020747.98+004735.4, SDSS-J090334.59+174717.7 ------------------------------------------------------------------------------------------------------------------------------------