6702( 7) - 05/02/96 13:53 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6702 Version: 7 Check-in Date: 02-May-1996 13:49:35 1.Proposal Title: Multicolor Imaging Polarimetry of Obscured Seyfert 2 Nuclei ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. Laura Kay Barnard College, Columbia University CoI: Dr. Ross Cohen University of California, San Diego N CoI: Dr. Robert Antonucci University of California, Santa Barbara N CoI: Todd Hurt University of California, Santa Barbara N CoI: Dr. Julian Krolik Johns Hopkins University N ------------------------------------------------------------------------------------ 6. Abstract The polarized flux spectra of at least 10 Seyfert 2 galaxies look like the flux spectra of Seyfert 1 nuclei, and the polarization position angles are generally perpendicular to the radio structure. This and other evidence suggests that all Seyfert 2s may have obscured Seyfert 1 nuclei visible only in reflected light. Off- nuclear dust clouds have been observed in some Seyfert 2s that reflect and bluen the nuclear light. Previously we have obtained FOS spectropolarimetry measurements on eight Seyfert 2 galaxies. Here we are proposing to use the FOC to conduct imaging polarimetry in two UV colors for 3 of these Seyferts to look for off-nuclear scattering mirrors and to resolve spatially the nuclear (electron scattering) mirrors. Polarimetric imaging provides a robust way to look for reflected radiation from hidden nuclei. Optical imaging polarimetry observations have been difficult from the ground because of the need for high spatial resolution and because of the dilution of this reflected light by starlight. The UV images will exclude almost all of the cool starlight that typically dilutes polarization, and comparisons of the images at the two wavelengths should allow us to distinguish between dust or electron scattering as the polarigenic mechanisms. We can then determine the geometry of the scattering regions and the physical nature of the scatterers. The electron scattering region size scale is a key model constraint. ------------------------------------------------------------------------------------ 6702( 7) - 05/02/96 13:53 - [ 2] Observations Description ------------------------ For each object we would like a series of FOC/96 polarization images using F275W and F342W, taking exposures in each color with POL0, POL60, and POL120. Our goal is to observe in the UV to resolve scattering mirrors near the nucleus and to reduce the dilution of the polarization by cool starlight. By measuring the polarized flux in 2 colors, we can calculate the polarized flux spectral index and distinguish between a dust scattered and an electron scattered AGN. We chose the FOC over WFPC--2 because FOC has higher angular resolution and is faster below 4500Angstroms ("Call for Proposals", p33). The FOC F320W filter has a poor PSF, and the F220W filter is not advantageous because the POL60 filter does not transmit below 1800Angstroms and drops to 65% transmittance at 2200Angstroms. Field of view was chosen to be the largest possible consistent with the required dynamic range. For Mark3 with the F275W filter we use the 512 * 512 zoomed format (7" * 14"). For Mark3 with the F342W filter and for Mark477 we use the 512 * 512 format (7" * 7"). Exposure times are 6 orbits for F275W and 3 orbits for F342W for Mark 477. The visibility period for these targets is 52 and 57 min. We will acquire guide stars and take a single polarization filter image with F275W during the first orbit, allowing for 7 min imaging overhead. The result is 37--42 min available for the first orbit, and 39--44 min for the subsequent orbits. The slightly lower exposure time in POL0 can be compensated by a slight scaling in the reductions. Mrk 3 fits into the 3 visits CVZ category, and thus we require only 3 orbits for F275W and 1 for F342W for the 3 POL filters. Images of Mrk 3, Mrk 463, and NGC 1068 suggest mirror sizes ~0.6 sq. arcsec, so we adapt that for the present objects, and plan to bin the polarization in 0.1" square bins, or larger in regions of low signal-to-noise. The fluxes are known from our FOS data and from archival images. If the polarized flux is measured to a 10% accuracy, we can fix the spectral index to an error of order 1, which will allow us to distinguish between dust (up to nu^3) and electron (nu^-1) scattering. Real Time Justification ----------------------- Mrk 3 fits into the 3 visit CVZ category. This is our most highly polarized object; if it cannot be scheduled into the CVZ we would like to observe it as with the others for 9 orbits. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6702( 7) - 05/02/96 13:53 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MARK3 GALAXY,Seyfert,NLR RA=06H 15M 36.27S +/-1", DEC=71D 2000 Z=0.0137 V = 13.34 02' 15.3" +/- 1", PLATE-ID=00M8 B-V = 1.15 2 MARK477 GALAXY,Seyfert,NLR RA=14H 40M 38.09S +/-1", DEC=53D 2000 Z=0.0382 V = 15.03 30' 16.0" +/- 1", PLATE-ID=01AL B-V = 1.02 6702( 7) - 05/02/96 13:53 - [ 4] Visit: 01 Visit Requirements: CVZ 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 MARK3 FOC/96 IMAGE 512X512 F275W, PIXEL=50x25 1 5190S POL0 ------------------------------------------------------------------------------------------------------------------------------------ 2 MARK3 FOC/96 IMAGE 512X512 F275W, PIXEL=50x25 1 5190S POL60 ------------------------------------------------------------------------------------------------------------------------------------ 3 MARK3 FOC/96 IMAGE 512X512 F275W, PIXEL=50x25 1 5190S POL120 ------------------------------------------------------------------------------------------------------------------------------------ 4 MARK3 FOC/96 IMAGE 512X512 F342W, 1 1700S POL120 ------------------------------------------------------------------------------------------------------------------------------------ 5 MARK3 FOC/96 IMAGE 512X512 F342W, 1 1700S POL60 ------------------------------------------------------------------------------------------------------------------------------------ 6 MARK3 FOC/96 IMAGE 512X512 F342W, 1 1700S POL0 ------------------------------------------------------------------------------------------------------------------------------------ 6702( 7) - 05/02/96 13:53 - [ 5] Visit: 02 Visit Requirements: GROUP 2-3 WITHIN 14D On Hold Comments: Additional Comments: GROUP 2-3 WITHIN 14D is included to try to keep roll angle the same for exposures in visits 2 and 3. Objects should be centered close to the same location if possible. GROUP WITHIN requirement may be relaxed if scheduling is too tightly constrained. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 MARK477 FOC/96 IMAGE 512X512 F275W, 1 3050S NO SPLIT POL0 ------------------------------------------------------------------------------------------------------------------------------------ 20 INTFLAT FOC/96 RESEAU 512X512 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 25 DARK FOC/96 IMAGE 512X512 F275W, 1 600S POL0 ------------------------------------------------------------------------------------------------------------------------------------ 30 MARK477 FOC/96 IMAGE 512X512 F275W, 1 3050S NO SPLIT POL0 ------------------------------------------------------------------------------------------------------------------------------------ 40 INTFLAT FOC/96 RESEAU 512X512 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 45 DARK FOC/96 IMAGE 512X512 F275W, 1 600S POL60 ------------------------------------------------------------------------------------------------------------------------------------ 50 MARK477 FOC/96 IMAGE 512X512 F275W, 1 3050S NO SPLIT POL60 ------------------------------------------------------------------------------------------------------------------------------------ 60 INTFLAT FOC/96 RESEAU 512X512 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 65 DARK FOC/96 IMAGE 512X512 F275W, 1 600S POL60 ------------------------------------------------------------------------------------------------------------------------------------ 70 MARK477 FOC/96 IMAGE 512X512 F275W, 1 3050S NO SPLIT POL60 ------------------------------------------------------------------------------------------------------------------------------------ 80 INTFLAT FOC/96 RESEAU 512X512 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 85 DARK FOC/96 IMAGE 512X512 F275W, 1 600S POL120 ------------------------------------------------------------------------------------------------------------------------------------ 90 MARK477 FOC/96 IMAGE 512X512 F275W, 1 3050S NO SPLIT POL120 ------------------------------------------------------------------------------------------------------------------------------------ 100 INTFLAT FOC/96 RESEAU 512X512 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 105 DARK FOC/96 IMAGE 512X512 F275W, 1 600S POL120 ------------------------------------------------------------------------------------------------------------------------------------ 110 MARK477 FOC/96 IMAGE 512X512 F275W, 1 3050S NO SPLIT POL120 ------------------------------------------------------------------------------------------------------------------------------------ 6702( 7) - 05/02/96 13:53 - [ 6] Visit: 03 Visit Requirements: SAME ORIENT AS 2 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 MARK477 FOC/96 IMAGE 512X512 F342W, 1 3050S NO SPLIT POL0 ------------------------------------------------------------------------------------------------------------------------------------ 20 INTFLAT FOC/96 RESEAU 512X512 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 25 DARK FOC/96 IMAGE 512X512 F342W, 1 600S POL60 ------------------------------------------------------------------------------------------------------------------------------------ 30 MARK477 FOC/96 IMAGE 512X512 F342W, 1 3050S NO SPLIT POL60 ------------------------------------------------------------------------------------------------------------------------------------ 40 INTFLAT FOC/96 RESEAU 512X512 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 45 DARK FOC/96 IMAGE 512X512 F342W, 1 600S POL120 ------------------------------------------------------------------------------------------------------------------------------------ 50 MARK477 FOC/96 IMAGE 512X512 F342W, 1 3050S NO SPLIT POL120 ------------------------------------------------------------------------------------------------------------------------------------ 6702( 7) - 05/02/96 13:53 - [ 7] Summary Form for Proposal 6702 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE RESEAU ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PIXEL=50x25 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ GROUP 2-3 WITHIN 14D NO SPLIT SAME ORIENT AS 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F275W,POL0 F275W,POL60 F275W,POL120 F342W,POL120 F342W,POL60 F342W,POL0 CLEAR ------------------------------------------------------------------------------------------------------------------------------------ Target Names MARK3 MARK477 INTFLAT DARK ------------------------------------------------------------------------------------------------------------------------------------