5960( 8) - 10/26/95 10:44 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5960 Version: 8 Check-in Date: ********** 1.Proposal Title: Identifying the Polarized Seyfert 1 Mirror in Markarian 463 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Alan Uomoto Johns Hopkins University CoI: Holland Ford Johns Hopkins University N CoI: Gerard Kriss Johns Hopkins University N CoI: Zlatan Tsvetanov Johns Hopkins University N CoI: Robert Antonucci University of California Santa Barbara N ------------------------------------------------------------------------------------ 6. Abstract Markarian 463 is a Seyfert 2 galaxy that shows a Seyfert 1 spectrum when viewed in polarized light (Miller & Goodrich 1990). One explanation is that light from an obscured Seyfert 1 is scattered into our line of sight (and polarized in the process) by material with a clear view of the nucleus. The nucleus of Mkn 463 is unresolved from the ground but HST/PC images (Uomoto et al. 1993) reveal a bright, subarcsec optical jet extending south of the nucleus. This jet is composed of a string of unresolved knots, some of which are likely to be the reflecting material. We propose using the FOC to obtain near UV images in polarized light to locate the scattering site. By combining this UV polarization information with existing ground based data we will determine the physical nature of the mirror by distinguishing between dust or electron scattering as the reflection mechanism. This proposal was awarded time in Cycle 3, but only an early acquisition image was taken. ------------------------------------------------------------------------------------ 5960( 8) - 10/26/95 10:44 - [ 2] Observations Description ------------------------ Three images of the nuclear region of Mkn 463 using the POL0, POL60, and POL120 polarizing prisms in conjunction with F342W will be obtained with the FOC. The nuclear complex consisting of the east nucleus and the optical jet extending 1 arcsec south fits neatly into the 7x7 arcsec FOC field of view and is clear of other strong nearby sources. An early acquisition image with the f/96 FOC will be used to precisely locate the target and update coordinates. The F342W filter was chosen to maximize the polarized S/N. Because the POL60 polarizer cuts off at a redder wavelength than the other two (2250 vs 1750 Angstroms) we felt it prudent to use a filter that strictly defines a spectral bandpass regardless of polarizer. The F342W filter does this well. (We originally chose F320W, but this filter is not now available.) The F342W bandpass is also blueward of the Balmer jump for the redshift of Mkn 463, which greatly reduces dilution by the light of old stellar populations, again enhancing polarized S/N. Finally, dust absorption is high in the UV, limiting potential contamination by polarized starlight. The observed count rate for the nucleus+jet complex in the near UV is 7.6* 10^-5 phot/cm^2/s/Angstrom (based on Miller & Goodrich 1990; these count rates assume we use F320W, which has 9% greater QT than F342W. This should not affect our results at all.). The jet accounts for about 1/3 of this flux (2.5* 10^-5) and this flux is distributed amongst at least 4 or 5 individual knots based on our PC images. Thus, an average knot has a flux of about 5* 10^-6 phot/cm^2/s/Angstrom. For unpolarized objects, this results in a count rate of about 4 Hz through the polarizers (equation 2 in the FOC Handbook Version 5.0). A previous version of this proposal, with identical science goals, was accepted for Cycle 3 and assigned the requested 10 hours of spacecraft time. Only the early acquisition image was obtained before the HST repair mission, however. This image shows the measured count rate for the brightest knot is 6 Hz, in agreement with our estimate (note that the post- COSTAR FOC is less sensitive than the pre-COSTAR version). The background due to the galaxy is higher than expected, however (the equivalent of about half the flux of the brightest knot per resolution element or 2 Hz). If we consider the case of 10% polarization, then the signal is 0.4 Hz in the brightest knot complex (more or less, depending on roll angle). For a desired S/N ratio of 10, t=100*{0.4+2(3.6+2)}/0.4^2 = 2 hr (equation 1 in the FOC Handbook Version 5.0) ignoring the small amount of instrument and non-galaxy background noise. Exposing a factor of two or three longer to measure the fainter components would seem appropriate but is probably not needed. Because the entire nuclear complex shows 10% polarization we expect individual knots to show higher values. Extending the exposure time to 2.5 hours per polarizer should be adequate and this comfortably fills four orbits. For three polarizing prisms, that's 12 orbits of long exposures plus one orbit of early acquisition, giving a total of 13 orbits. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5960( 8) - 10/26/95 10:44 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5960( 8) - 10/26/95 10:44 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MKN463 GALAXY,SPIRAL,SEYFERT,U RA=13H 56M 2.823S +/- J2000.0 Z=0.0506 V=20.0+/-1.0 LTRALUMINOUS IR 0.005S,DEC=18D 22' 19.81" +/- GAL,INTERACTING GALAXY 0.05", PLATE-ID=019M 2 MKN463-UPD GALAXY,SPIRAL,SEYFERT,U RA=13H 56M 2.936S +/- J2000.0 Z=0.0506 V=20.0+/-1.0 LTRALUMINOUS IR 0.005S,DEC=18D 22' 17.68" +/- GAL,INTERACTING GALAXY 0.05", PLATE-ID=019M Comments: Target coordinates updated based on early acq images from Visit 1. 5960( 8) - 10/26/95 10:44 - [ 5] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Early acquisition Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MKN463 FOC/96 IMAGE 512x512 F342W 1 2100S ------------------------------------------------------------------------------------------------------------------------------------ 5960( 8) - 10/26/95 10:44 - [ 6] Visit: 02 Visit Requirements: ORIENT 133D TO 133D On Hold Comments: Additional Comments: COORDS HAVE NOW BEEN UPDATED Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 2 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 1 2100S 0 ------------------------------------------------------------------------------------------------------------------------------------ 3 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 1 2700S 0 ------------------------------------------------------------------------------------------------------------------------------------ 4 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 2 2700S 120 ------------------------------------------------------------------------------------------------------------------------------------ 6 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 2 2700S 60 ------------------------------------------------------------------------------------------------------------------------------------ 5960( 8) - 10/26/95 10:44 - [ 7] Visit: 03 Visit Requirements: ORIENT 133D TO 133D On Hold Comments: Additional Comments: COORDS HAVE NOW BEEN UPDATED Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 8 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 1 2100S 120 ------------------------------------------------------------------------------------------------------------------------------------ 9 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 1 2700S 120 ------------------------------------------------------------------------------------------------------------------------------------ 10 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 2 2700S 0 ------------------------------------------------------------------------------------------------------------------------------------ 12 MKN463-UPD FOC/96 IMAGE 512x512 F342W,POL 2 2700S 60 ------------------------------------------------------------------------------------------------------------------------------------ 5960( 8) - 10/26/95 10:44 - [ 8] Summary Form for Proposal 5960 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 133D TO 133D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F342W F342W,POL0 F342W,POL120 F342W,POL60 ------------------------------------------------------------------------------------------------------------------------------------ Target Names MKN463 MKN463-UPD ------------------------------------------------------------------------------------------------------------------------------------