14749( 4) - 14-Aug-2017 14:51:49 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14749 Version: 4 Check-in Time: 14-Aug-2017 14:51:49 STScI Edit Number: 1 Title Low redshift Lyman-alpha blobs ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Mischa Schirmer Gemini Observatory, Southern Operations Y CoI: Dr. William Clifford Keel University of Alabama N CoI: Dr. Nancy A. Levenson Gemini Observatory, Southern Operations N CoI: Dr. Hai Fu University of Iowa N CoI: Dr. Sangeeta Malhotra Arizona State University N CoI: Dr. Paul Torrey Massachusetts Institute of Technology N CoI: Rebecca Davies Australian National University N CoI: Dr. Tohru Nagao Ehime University N CoI: Dr. James Turner Gemini Observatory, Southern Operations N CoI: Dr. Ruben Diaz Gemini Observatory, Southern Operations N ------------------------------------------------------------------------------------ Abstract Lyman-alpha blobs (LABs) are luminous nebula at redshifts of 2 and beyond. Their nature and ionization sources are mysterious. The lack of accessible diagnostic emission lines and the poorly understood Lyman-alpha escape mechanism have so far prevented a consistent physical picture of LABs. We suggest that many LABs harbor transient AGN that have recently and quickly faded from our view; the Ly-alpha photons from the earlier quasar phase, however, are resonantly scattered and slowly released over times much longer than the LABs' light crossing time. These ionization echoes naturally explain the severe power deficits observed in LABs. We have identified a rare population of ultra-luminous [OIII] ionization echoes around transient AGN at redshifts z=0.3. They share many characteristics of LABs, including high Lyman-alpha luminosities of up to 7e43 erg/s as suggested by GALEX FUV images. We ask to observe three targets to verify the strong Lyman-alpha emission using ACS/SBC. This would prove that LABs may still exist in the Universe 7 billion years later than most other LABs known. It would also show that fading AGN explain the power deficits of many LABs, solving a puzzle that has been standing for over a decade. This proposal exploits the unique far-UV capabilities of HST. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program aims to obtain far-UV spectra and images with ACS/SBC, for a total of three targets. The targets are galaxies at redshift 0.3, embedded in luminous clouds of ionized gas. The clouds have diameters between 10-25 arcseconds, and we want to determine their Lyman-alpha properties. Each target has one visit, consisting of two orbits. In the first orbit, we take a slitless spectrum of the source, followed by an image in the second orbit. The science exposures (spectrum and image) are split into two sub-exposures of approximately equal length (1300s), using a line dither pattern to reject 14749( 4) - 14-Aug-2017 14:51:49 - [ 2] detector defects. The purpose of the spectrum (first orbit) is to determine the total amount of flux in the Lyman-alpha line, and to measure the flux in the continuum (if any). The purpose of the image (second orbit) is to obtain a deeper view to determine morphology and size. Ihe image is also needed to reduce the slitless spectrum. Absolute flux calibration is important. This will mainly be based on the slitless spectrum, where we can isolate the effects of the red leaks. All our targets are covered by GALEX imaging, no FUV-bright stars are in the field of view. ------------------------------------------------------------------------------------ 14749( 4) - 14-Aug-2017 14:51:49 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-011341+0 GALAXY, EMISSION LINE RA=01H13M41.1100S +/- 0.15", J2000 Z = V = 19.8 +/- 0.1 r=18.5, GALEX FUV=15.9 10608 NEBULA, LYMAN ALPHA DEC=+01D06'8.50" +/- 0.15" 0.281 microjansky integrated over the entire CLOUD, NLR, QUASAR source Reference Frame: ICRS Extended: YES Comments: Source diameter: 5x15 arcsec ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-115544-0 GALAXY, EMISSION LINE RA=11H55M44.5867S +/- 0.15", J2000 Z = V = 18.5 +/- 0.1 r=17.9, GALEX FUV=40.8 14740 NEBULA, LYMAN ALPHA DEC=-01D47'41.76" +/- 0.15" 0.306 microjansky integrated over the entire CLOUD, NLR, QUASAR source Reference Frame: ICRS Extended: YES Comments: Source diameter: 20x25 arcsec A small offset in DEC has been introduced with respect to the nucleus of the galaxy. This is to better accomodate the extended nebulosity in the SBC field of view. The offset is noticable in the target confirmation chart. ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-224024-0 GALAXY, EMISSION LINE RA=22H40M24.1100S +/- 0.15", J2000 Z = V = 19.4 +/- 0.1 r=18.3, GALEX FUV=21.2 92748 NEBULA, LYMAN ALPHA DEC=-09D27'48.10" +/- 0.15" 0.326 microjansky integrated over the entire CLOUD, NLR, QUASAR source Reference Frame: ICRS Extended: YES Comments: Source diameter: 6x8 arcsec ------------------------------------------------------------------------------------------------------------------------------------ 14749( 4) - 14-Aug-2017 14:51:49 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-SBC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.472 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 44.4 Angle_Between_Sides Center_Pattern NO Pattern_Comments: We choose the default line pattern to reject detector blemishes ------------------------------------------------------------------------------------------------------------------------------------ 14749( 4) - 14-Aug-2017 14:51:49 - [ 5] Visit: 01 (J0113+0106) Visit Requirements: SCHED 80% 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 GAL-011341+ ACS/SBC ACCUM SBC F140LP 1 1100 S PATTERN 1 1-3 010608 (2200 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-011341+ ACS/SBC ACCUM SBC F165LP 1 300 S 010608 see below (600 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-011341+ ACS/SBC ACCUM SBC PR130L 1 1000 S 010608 see below (2239 S) Comments: Slitless spectroscopic image ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ GAL-011341+010608 1 ACS/SBC ACCUM SBC F140LP 1 none none none 1 N/A GAL-011341+010608 1 ACS/SBC ACCUM SBC F140LP 2 none none none 2 N/A GAL-011341+010608 2 ACS/SBC ACCUM SBC F165LP 1 none none none 1 300.0 S GAL-011341+010608 2 ACS/SBC ACCUM SBC F165LP 2 none none none 2 300.0 S GAL-011341+010608 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 1064.0 S GAL-011341+010608 3 ACS/SBC ACCUM SBC PR130L 2 none none none 2 1175.0 S 14749( 4) - 14-Aug-2017 14:51:49 - [ 6] Visit: 02 (J1155-0147) Visit Requirements: SCHED 80% On Hold Comments: Additional Comments: Target coordinates include a small offset with respect to the nucleus of galaxy to better accomodate the extended flux. 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 GAL-115544- ACS/SBC ACCUM SBC F140LP 1 1100 S PATTERN 1 1-3 014740 (2200 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-115544- ACS/SBC ACCUM SBC F165LP 1 300 S (600 014740 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-115544- ACS/SBC ACCUM SBC PR130L 1 1100 S 014740 see below (2239 S) Comments: Slitless spectroscopic image ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ GAL-115544-014740 1 ACS/SBC ACCUM SBC F140LP 1 none none none 1 N/A GAL-115544-014740 1 ACS/SBC ACCUM SBC F140LP 2 none none none 2 N/A GAL-115544-014740 2 ACS/SBC ACCUM SBC F165LP 1 none none none 1 N/A GAL-115544-014740 2 ACS/SBC ACCUM SBC F165LP 2 none none none 2 N/A GAL-115544-014740 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 1064.0 S GAL-115544-014740 3 ACS/SBC ACCUM SBC PR130L 2 none none none 2 1175.0 S 14749( 4) - 14-Aug-2017 14:51:49 - [ 7] Visit: 03 (J2240-0927) Visit Requirements: SCHED 80% 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 GAL-224024- ACS/SBC ACCUM SBC F140LP 1 1100 S PATTERN 1 1-3 092748 (2200 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-224024- ACS/SBC ACCUM SBC F165LP 1 300 S (600 092748 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-224024- ACS/SBC ACCUM SBC PR130L 1 1100 S 092748 see below (2237 S) Comments: Slitless spectroscopic image ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ GAL-224024-092748 1 ACS/SBC ACCUM SBC F140LP 1 none none none 1 N/A GAL-224024-092748 1 ACS/SBC ACCUM SBC F140LP 2 none none none 2 N/A GAL-224024-092748 2 ACS/SBC ACCUM SBC F165LP 1 none none none 1 N/A GAL-224024-092748 2 ACS/SBC ACCUM SBC F165LP 2 none none none 2 N/A GAL-224024-092748 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 1063.0 S GAL-224024-092748 3 ACS/SBC ACCUM SBC PR130L 2 none none none 2 1174.0 S 14749( 4) - 14-Aug-2017 14:51:49 - [ 8] Visit: 52 (J1155-0147) Visit Requirements: SCHED 80% On Hold Comments: Additional Comments: Target coordinates include a small offset with respect to the nucleus of galaxy to better accomodate the extended flux. 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 GAL-115544- ACS/SBC ACCUM SBC F140LP 1 1100 S PATTERN 1 1-3 014740 (2200 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-115544- ACS/SBC ACCUM SBC F165LP 1 300 S (600 014740 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-115544- ACS/SBC ACCUM SBC PR130L 1 1100 S 014740 see below (2239 S) Comments: Slitless spectroscopic image ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ GAL-115544-014740 1 ACS/SBC ACCUM SBC F140LP 1 none none none 1 N/A GAL-115544-014740 1 ACS/SBC ACCUM SBC F140LP 2 none none none 2 N/A GAL-115544-014740 2 ACS/SBC ACCUM SBC F165LP 1 none none none 1 N/A GAL-115544-014740 2 ACS/SBC ACCUM SBC F165LP 2 none none none 2 N/A GAL-115544-014740 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 1064.0 S GAL-115544-014740 3 ACS/SBC ACCUM SBC PR130L 2 none none none 2 1175.0 S 14749( 4) - 14-Aug-2017 14:51:49 - [ 9] Summary Form for Proposal 14749 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures SBC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/SBC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1-3, SCHED 80% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F140LP, F165LP, PR130L ------------------------------------------------------------------------------------------------------------------------------------ Target Names GAL-011341+010608, GAL-115544-014740, GAL-224024-092748 ------------------------------------------------------------------------------------------------------------------------------------