6444( 5) - 04/16/96 15:17 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6444 Version: 5 Check-in Date: 16-Apr-1996 15:14:15 1.Proposal Title: Ultraviolet Imaging Polarimetry of the Low-Redshift BALQSO Mrk 231 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle GALAXIES & CLUSTERS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Paul Smith University of Arizona CoI: Gary Schmidt University of Arizona N CoI: Dean Hines University of Arizona N ------------------------------------------------------------------------------------ 6. Abstract Markarian 231 is an extremely luminous galaxy with a peculiar Seyfert 1 nucleus that exhibits several absorption line systems, extremely powerful Fe II and infrared emission, and high optical and near-UV polarization. Scattering of nuclear light into our line of sight by dust distributed around the AGN produces the observed polarized flux. Several recent studies have established a strong link between Mrk 231 and broad absorption line quasars (BALQSOs). Its low redshift offers an opportunity to investigate the nuclear structure of a BALQSO-like object in more detail than is possible for the far more distant members of this class of AGN, and thereby test current BALQSO/normal QSO ``unification'' models. Direct imaging of the nucleus would be extremely difficult to interpret given the large amount of circumnuclear scattering. Therefore, we propose to obtain full polarization images of Mrk 231 in ultraviolet light to map the scattering regions within ~1 kpc of the nucleus. Individual scattering clouds can be expected to reach polarizations of >~50\ This, combined with the excellent spatial resolution of the FOC (~25 pc at the distance of Mrk 231), will allow for a detailed analysis of the inner regions of Mrk 231 and easily distinguish scattering clouds from unpolarized sources of nuclear ultraviolet flux. Our proposed observations have the potential to answer several fundamental questions concerning the nuclear structure of Mrk 231 (and by analogy, BALQSOs). ------------------------------------------------------------------------------------ 6444( 5) - 04/16/96 15:17 - [ 2] Observations Description ------------------------ We have chosen the FOC/96 over the Planetary Camera of WFPC2 because it achieves higher spatial resolution as well as having higher sensitivity in the ultraviolet. The 128*128 format of FOC samples the inner 1.5*1.5 kpc^2 of the object and allows a much higher linear counting rate than the standard 512*512 format. All images will be taken through the F346M filter to isolate the peak of the polarization spectrum as measured by the FOS (P ~ 15\\ and avoid major emission lines. Two exposures of 2600 s each will be taken using the three polarizing prisms (POL0, POL60, and POL120). Each exposure plus FOC and HST overheads require 1 orbit, thus a polarization map of the nuclear region of Mrk 231 necessitates 6 orbits. Because the small FOC imaging format will be used, an interactive acquisition is required to center the nucleus in the 1arcs8*1arcs8 field of view. This acquisition will essentially take 1 orbit. The exposure time was calculated assuming that the flux measured in the 1arcs4*4arcs3 aperture of the FOS (sim4*10^-15 ergs cm^-2 s^- 1 Angstrom^-1; Smith et al. 1995) is uniformly distributed in the inner arcsec^2. Since the AGN is unresolved in ground- based observations, a large fraction of the flux must originate from this small region. The count rate in this region with the F346M+POLx combination is expected to be sim270 ct s^-1, or 0.068 ct s^-1 pix^- 1 (the background is estimated to be sim9*10^-4 ct s^-1 pix^-1). In this case, there would be ~1400 cts from Mrk 231 (~20 background counts) in 5200 s per resolution element (roughly 2*2 pix^2). This yields an uncertainty based on Poisson statistics in the polarization of Sigma_P ~ 2\\ per resolution element --- less than or comparable to the systematic uncertainties noted in the FOC Handbook and well below the levels of polarization expected to be present in the object. begintabularlll Cycle 6 & Primary Orbits:7 & Exposures:6, endtabular Real Time Justification ----------------------- Centering of MRK231 into the 128x128 field of view requires an INTeractive ACQuisition. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6444( 5) - 04/16/96 15:17 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MRK231 GALAXY,Seyfert RA=12H 56M 14.12S +/- 1.0", 2000 Z=0.041 F(5500)=12.0+/-1.0e-15 DEC=56D 52' 25.02" +/- 1.0", F(3000)=3.0+/-0.5e-15 PLATE-ID=01R1 6444( 5) - 04/16/96 15:17 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 MRK231 FOC/96 ACQ 512X512 F346M,POL3480 PIXEL=25x25 1 300S INT ACQ FOR 11-72 0,F1ND ------------------------------------------------------------------------------------------------------------------------------------ 11 MRK231 FOC/96 IMAGE 128X128 F210M 2100 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 14 INTFLAT FOC/96 RESEAU 128X128 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 20 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1139S NO SPLIT; POS TARG 0.0,0.05 0 ------------------------------------------------------------------------------------------------------------------------------------ 21 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1139S NO SPLIT; POS TARG 0.05,-0.05 0 ------------------------------------------------------------------------------------------------------------------------------------ 22 INTFLAT FOC/96 RESEAU 128X128 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 30 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT 60 ------------------------------------------------------------------------------------------------------------------------------------ 31 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT; POS TARG -0.05,-0.05 60 ------------------------------------------------------------------------------------------------------------------------------------ 32 INTFLAT FOC/96 RESEAU 128X128 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 40 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT 120 ------------------------------------------------------------------------------------------------------------------------------------ 41 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT; POS TARG -0.05,0.05 120 ------------------------------------------------------------------------------------------------------------------------------------ 42 INTFLAT FOC/96 RESEAU 128X128 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 50 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT 0 ------------------------------------------------------------------------------------------------------------------------------------ 51 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT; POS TARG 0.05,-0.05 0 ------------------------------------------------------------------------------------------------------------------------------------ 52 INTFLAT FOC/96 RESEAU 128X128 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 60 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT; POS TARG -0.05,0.05 60 ------------------------------------------------------------------------------------------------------------------------------------ 61 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT; POS TARG 0.05,0.05 60 ------------------------------------------------------------------------------------------------------------------------------------ 62 INTFLAT FOC/96 RESEAU 128X128 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 6444( 5) - 04/16/96 15:17 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 70 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT 120 ------------------------------------------------------------------------------------------------------------------------------------ 71 MRK231 FOC/96 IMAGE 128X128 F346M,POL3480 1 1270S NO SPLIT; POS TARG 0.05,-0.05 120 ------------------------------------------------------------------------------------------------------------------------------------ 72 INTFLAT FOC/96 RESEAU 128X128 CLEAR 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 6444( 5) - 04/16/96 15:17 - [ 6] Summary Form for Proposal 6444 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ IMAGE RESEAU ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PIXEL=25x25 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements INT ACQ FOR 11-72 NO SPLIT; POS TARG 0.0,0.05 NO SPLIT; POS TARG 0.05,-0.05 NO SPLIT NO SPLIT; POS TARG -0.05,-0.05 NO SPLIT; POS TARG -0.05,0.05 NO SPLIT; POS TARG 0.05,0.05 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F346M,POL0,F1ND F210M CLEAR F346M,POL0 F346M,POL60 F346M,POL120 ------------------------------------------------------------------------------------------------------------------------------------ Target Names MRK231 INTFLAT ------------------------------------------------------------------------------------------------------------------------------------