5937( 4) - 09/08/95 11:26 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5937 Version: 4 Check-in Date: ********** 1.Proposal Title: A Gravitational Lens Telescope: Ly-Alpha Imagery of Q2237+0305 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Quasars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Edwin L. Turner Princeton University Observatory CoI: Joachim Wambsganss Max-Planck Institute for Astrophysics N ------------------------------------------------------------------------------------ 6. Abstract Q2237+0305, aka Huchra's lens or Einstein's cross, is one of the best understood gravitational lens systems, in part because the lensing galaxy is unusually nearby (z=0.04). The continuum emitting core of the z=1.69 quasar which is the background source lies only about 0.1 arcsec from perfect alignment directly behind the galaxy, and its images (which fall about 1 arcsec from the center of the galaxy) are magnified by factors at least of order 10. Any emission in the region near the quasar core will also be strongly magnified. Such emission would be resolved from the core images by HST even if it were as small as 50h^-1 parsec (0.01 arcsec intrinsic angular size). We propose to obtain deep WFPC2 images in the F336W and F300W bands which are fortuitously well matched to the redshifted Ly-Alpha emission line of the source. Such emission can be mapped back into the source plane (via available models of the system) to provide a map of the HII region surrounding the quasar at otherwise inaccessible resolution. In addition, Ly-Alpha emission regions in the quasar's host galaxy may be detected with some degree of lensing boost (depending on its location relative to the quasar core), probably with characteristic distorted arc- like shapes. Reversing the problem, resolved emission will also provide additional, potentially powerful constraints on lens models of Q2237+0305 and thus further constrain the galaxy's mass distribution. ------------------------------------------------------------------------------------ 5937( 4) - 09/08/95 11:26 - [ 2] Observations Description ------------------------ We wish to obtain images through both F336W (the Ly-alpha band) and F300W (the reference band for dust and other broadband features) using both the PC chip (for subtraction of the core images to look for relatively high surface brightness resolved features very near the core images) and a WF chip (to look for lower surface brightness emission well separated from the core images). We propose to devote 2 orbits to each type of chip with F300W and 3 orbits each with F336W for a total of 10 orbits. The criterion for individual exposure times is to avoid bleeding of the core images in the WF exposures and to keep the core images well within the linear range in the PC exposures so that they may be accurately subtracted. Unfortuantely, in this context (but not others variable due to microlensing events and perhaps intrinsic fluctuations, so that it is not possible to predict their brightnesses in advance. We have, therefore, used predictions of their rough typical brightnesses based on Yee's photometry (extrapolated by the observed spectral index, -1.5, into the UV) and then allowed fairly generous safety margins to absorb microlensing or other variations. Based on these calculations we adopt individual WF exposures of 17 to 21 minutes each and individual PC exposures of 11 to 13 minutes. After ``orbit packing" calculations, we find that this plan gives totals of 126 minutes in 6 exposures for WF chip with F336W, 76 minutes in 4 exposures for WF chip with F300W, 112 minutes in 9 exposures for PC chip with F336W, and 78 minutes in 6 exposures for PC chip with F300W. Real Time Justification ----------------------- None. Calibration Justification ------------------------- None. Additional Comments ------------------- None. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5937( 4) - 09/08/95 11:26 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 G2237+0305 GALAXY, GRAVITATIONAL RA = 22H 40M 29.78S +/- 0.06S, J2000 Z = 1.69 V = 17.5 +/- 1.5 B-V = 0.5 +/- 1.0 LENS, QSO, SPIRAL DEC = +3D 21' 29.4" +/- 1" Comments: FLUX VALUES ARE NOT AVAILABLE IN THE UV WHERE WE ARE IMAGING. ALSO, MICROLENSING EVENTS PRODUCE STRONG IMAGE VARIATIONS AND THERE IS EVIDENCE FOR EXTINCTION BY DUST IN THE LENS. THE FLUX OF THE LY-ALPHA FEATURES FOR WHICH WE ARE SEARCHING IS ENTIRELY UNKNOWN. SEE OBSERVING_DESCRIPTION ABOVE FOR STRATEGY. 5937( 4) - 09/08/95 11:26 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 G2237+0305 WFPC2 IMAGE WF3-FIX F300W CR-SPLIT = NO 1 1100S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 2 G2237+0305 WFPC2 IMAGE WF3-FIX F300W CR-SPLIT = NO 1 1100S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 3 G2237+0305 WFPC2 IMAGE WF3-FIX F300W CR-SPLIT = NO 1 1300S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 4 G2237+0305 WFPC2 IMAGE WF3-FIX F300W CR-SPLIT = NO 1 1300S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 5 G2237+0305 WFPC2 IMAGE WF3-FIX F336W CR-SPLIT = NO 1 1100S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 6 G2237+0305 WFPC2 IMAGE WF3-FIX F336W CR-SPLIT = NO 1 1200S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 7 G2237+0305 WFPC2 IMAGE WF3-FIX F336W CR-SPLIT = NO 1 1200S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 8 G2237+0305 WFPC2 IMAGE WF3-FIX F336W CR-SPLIT = NO 1 1100S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 9 G2237+0305 WFPC2 IMAGE WF3-FIX F336W CR-SPLIT = NO 1 1200S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 10 G2237+0305 WFPC2 IMAGE WF3-FIX F336W CR-SPLIT = NO 1 1200S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 5937( 4) - 09/08/95 11:26 - [ 5] Visit: 02 Visit Requirements: SAME ORIENT AS 1 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 700S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 12 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 700S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 13 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 700S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 14 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 800S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 15 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 700S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 16 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 700S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 17 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 800S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 18 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 800S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 19 G2237+0305 WFPC2 IMAGE PC1-FIX F336W CR-SPLIT = NO 1 800S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 20 G2237+0305 WFPC2 IMAGE PC1-FIX F300W CR-SPLIT = NO 1 700S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 21 G2237+0305 WFPC2 IMAGE PC1-FIX F300W CR-SPLIT = NO 1 800S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 22 G2237+0305 WFPC2 IMAGE PC1-FIX F300W CR-SPLIT = NO 1 700S POS TARG 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 23 G2237+0305 WFPC2 IMAGE PC1-FIX F300W CR-SPLIT = NO 1 700S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 24 G2237+0305 WFPC2 IMAGE PC1-FIX F300W CR-SPLIT = NO 1 800S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 25 G2237+0305 WFPC2 IMAGE PC1-FIX F300W CR-SPLIT = NO 1 800S POS TARG 0.25,0.25 ------------------------------------------------------------------------------------------------------------------------------------ 5937( 4) - 09/08/95 11:26 - [ 6] Summary Form for Proposal 5937 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Quasars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG 0,0 POS TARG 0.25,0.25 SAME ORIENT AS 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F300W F336W ------------------------------------------------------------------------------------------------------------------------------------ Target Names G2237+0305 ------------------------------------------------------------------------------------------------------------------------------------