15247( 2) - 05-Dec-2018 20:40:00 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15247 Version: 2 Check-in Time: 05-Dec-2018 20:40:00 STScI Edit Number: 0 Title Low redshift Lyman-alpha blobs ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Mischa Schirmer Max-Planck-Institut fur Astronomie, Y Heidelberg CoI: Dr. Taiki Kawamuro National Astronomical Observatory of Japan N (NAOJ) CoI: Dr. Claudio Ricci Pontificia Universidad Catolica de Chile N CoI: Dr. Kohei Ichikawa Columbia University in the City of New N York CoI: Dr. Sangeeta Malhotra NASA Goddard Space Flight Center N CoI: Dr. William Clifford Keel University of Alabama N CoI: Dr. Hai Fu University of Iowa N CoI: Prof. Paul Torrey University of Florida N CoI: Rebecca Davies Max-Planck-Institut fur extraterrestrische N Physik 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 have remained 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 nearly two decades. In combination with our existing ground-based imaging and 3D spectroscopy, and soft-and hard X-ray data, we will exploit the HST far-UV data to also study the Lyman-alpha escape mechanism. This proposal is a continuation of our cycle 24 allocation, to complete the far-UV data for the most luminous LABs in our sample. 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 15247( 2) - 05-Dec-2018 20:40:00 - [ 2] 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 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. ------------------------------------------------------------------------------------ 15247( 2) - 05-Dec-2018 20:40:00 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-134709+5 GALAXY, EMISSION LINE RA=13H47M9.1260S +/- 0.15", J2000 Z = V = 19.8 +/- 0.1 r=18.7, GALEX FUV=31.0 45310 NEBULA, LYMAN ALPHA DEC=+54D53'10.93" +/- 0.15" 0.332 microjansky integrated over the entire CLOUD, NLR, QUASAR source Reference Frame: ICRS Extended: YES Comments: Source diameter: 5x9 arcsec ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-145533+0 GALAXY, EMISSION LINE RA=14H55M33.6870S +/- 0.15", J2000 Z = V = 19.5 +/- 0.1 r=18.5, GALEX FUV=19.8 44643 NEBULA, LYMAN ALPHA DEC=+04D46'43.21" +/- 0.15" 0.334 microjansky integrated over the entire CLOUD, NLR, QUASAR source Reference Frame: ICRS Extended: YES Comments: Source diameter: 6x9 arcsec ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-150517+1 GALAXY, EMISSION LINE RA=15H05M17.6300S +/- 0.15", J2000 Z = V = 19.2 +/- 0.1 r=17.9, GALEX FUV=22.7 94444 NEBULA, LYMAN ALPHA DEC=+19D44'44.83" +/- 0.15" 0.341 microjansky integrated over the entire CLOUD, NLR, QUASAR source Reference Frame: ICRS Extended: YES Comments: Source diameter: 7x7 arcsec ------------------------------------------------------------------------------------------------------------------------------------ 15247( 2) - 05-Dec-2018 20:40:00 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 15247( 2) - 05-Dec-2018 20:40:00 - [ 5] Visit: 01 (J1347+5453) Visit Requirements: SCHED 80%; ORIENT 70D TO 185 D; ORIENT 250D TO 5 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 GAL-134709+ ACS/SBC ACCUM SBC F140LP 1 1100 S PATTERN 1 1-3 545310 see below (2264 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-134709+ ACS/SBC ACCUM SBC F165LP 1 300 S 545310 see below (664 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-134709+ ACS/SBC ACCUM SBC PR130L 1 1000 S 545310 see below (2303 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-134709+545310 1 ACS/SBC ACCUM SBC F140LP 1 none none none 1 1132.0 S GAL-134709+545310 1 ACS/SBC ACCUM SBC F140LP 2 none none none 2 1132.0 S GAL-134709+545310 2 ACS/SBC ACCUM SBC F165LP 1 none none none 1 332.0 S GAL-134709+545310 2 ACS/SBC ACCUM SBC F165LP 2 none none none 2 332.0 S GAL-134709+545310 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 1096.0 S GAL-134709+545310 3 ACS/SBC ACCUM SBC PR130L 2 none none none 2 1207.0 S 15247( 2) - 05-Dec-2018 20:40:00 - [ 6] Visit: 02 (J1455+0446) Visit Requirements: SCHED 80%; ORIENT 10D TO 50 D; ORIENT 190D TO 230 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 GAL-145533+ ACS/SBC ACCUM SBC F140LP 1 1100 S PATTERN 1 1-3 044643 see below (2198 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-145533+ ACS/SBC ACCUM SBC F165LP 1 300 S 044643 see below (598 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-145533+ ACS/SBC ACCUM SBC PR130L 1 1100 S 044643 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-145533+044643 1 ACS/SBC ACCUM SBC F140LP 1 none none none 1 1099.0 S GAL-145533+044643 1 ACS/SBC ACCUM SBC F140LP 2 none none none 2 1099.0 S GAL-145533+044643 2 ACS/SBC ACCUM SBC F165LP 1 none none none 1 299.0 S GAL-145533+044643 2 ACS/SBC ACCUM SBC F165LP 2 none none none 2 299.0 S GAL-145533+044643 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 1063.0 S GAL-145533+044643 3 ACS/SBC ACCUM SBC PR130L 2 none none none 2 1174.0 S 15247( 2) - 05-Dec-2018 20:40:00 - [ 7] Visit: 03 (J1505+1944) Visit Requirements: SCHED 80%; ORIENT 30D TO 100 D; ORIENT 210D TO 280 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 GAL-150517+ ACS/SBC ACCUM SBC F140LP 1 1100 S PATTERN 1 1-3 194444 see below (2206 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-150517+ ACS/SBC ACCUM SBC F165LP 1 300 S 194444 see below (606 S) Comments: Single image ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-150517+ ACS/SBC ACCUM SBC PR130L 1 1100 S 194444 see below (2243 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-150517+194444 1 ACS/SBC ACCUM SBC F140LP 1 none none none 1 1103.0 S GAL-150517+194444 1 ACS/SBC ACCUM SBC F140LP 2 none none none 2 1103.0 S GAL-150517+194444 2 ACS/SBC ACCUM SBC F165LP 1 none none none 1 303.0 S GAL-150517+194444 2 ACS/SBC ACCUM SBC F165LP 2 none none none 2 303.0 S GAL-150517+194444 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 1066.0 S GAL-150517+194444 3 ACS/SBC ACCUM SBC PR130L 2 none none none 2 1177.0 S 15247( 2) - 05-Dec-2018 20:40:00 - [ 8] Summary Form for Proposal 15247 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures SBC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/SBC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 10D TO 50 D, ORIENT 190D TO 230 D, ORIENT 210D TO 280 D, ORIENT 250D TO 5 D, ORIENT 30D TO 100 D, ORIENT 70D TO 185 D, PATTERN 1 1-3, SCHED 80% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F140LP, F165LP, PR130L ------------------------------------------------------------------------------------------------------------------------------------ Target Names GAL-134709+545310, GAL-145533+044643, GAL-150517+194444 ------------------------------------------------------------------------------------------------------------------------------------