5938( 6) - 03/14/96 14:09 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5938 Version: 6 Check-in Date: 14-Mar-1996 13:51:54 1.Proposal Title: The Underlying Nature of Nearby BL Lac Objects ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: C. Megan Urry Space Telescope Science Institute CoI: Riccardo Scarpa Osservatorio Astronomico di Padova N CoI: Aldo Treves SISSA/ISAS N CoI: Joseph E. Pesce Space Telescope Science Institute Y CoI: Renato Falomo Osservatorio Astronomico di Padova N CoI: Mauro Giavalisco Space Telescope Science Institute N CoI: Rita M. Sambruna Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract The host galaxies and near environments of BL Lac objects are an important clue to their underlying nature, revealing whether they are relativistically beamed low- luminosity radio galaxies or luminous distant quasars gravitationally microlensed by foreground galaxies. In the former case, the host galaxies should be bright ellipticals in rich cluster environments; in the latter, the BL Lac nuclei should be off- center and some host galaxies should be spirals. High resolution imaging may also reveal the presence of close companions, indicative of the importance of interactions to the blazar phenomenon. We propose to study the host galaxies and environments of four radio-selected BL Lac objects from a well-defined, complete sample at redshiftS ~< 0.3. No comparable HST data exist or are planned for any BL Lac objects. ------------------------------------------------------------------------------------ 5938( 6) - 03/14/96 14:09 - [ 2] Observations Description ------------------------ We propose WFPC2 images in the F814W filter (which corresponds approximately R at the median sample redshift). We will obtain several short exposures to get the central point source without saturating the detector and several medium and long ones to get the galaxy fuzz. The target may be saturated (and may bleed) in the medium and long exposures. We will rotate the spacecraft between exposure series to better characterize the PSF (i.e. short exp., medium exp., long exp., roll, short, medium, long), and the two visits per target MUST be sequential, in consecutive orbits, with no intervention but the roll. The point source will be centered in the PC to get the best resolution in the inner part of the galaxy; the WF chips will give the outer parts of the galaxy and the near environment (~< 400 kpc projected distance from the BL Lac object). We calculated the required integration time to get a S/N ratio of 3 at the 23 mag/arcsec^2 isophote which simulations show is sufficient to determine the host galaxy properties. After filling out the orbits, we get substantially longer integrations in some cases. The filter chosen is frequently used; no special calibration exposures are required but PSF monitoring in this filter would greatly enhance our program. Real Time Justification ----------------------- We have no special scheduling requirments. Calibration Justification ------------------------- We have no special calibration requirments. PSF monitoring in the PC with the F814W filter would help us better subtract the nuclear point source, which is expected to be the limiting factor in detecting the host galaxy. Additional Comments ------------------- We require the spacecraft to roll between sets of observations (one set of short exposure, medium exposure, and long exposure per orbit). It is imperative that for each target the two visits are sequential, in consecutive orbits, with no intervention but the roll. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: *STSCI*3700 San Martin Drive*Baltimore, MD. 21218 Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5938( 6) - 03/14/96 14:09 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PKS2254+074 GALAXY,BL Lac RA=22H 57M 17.3S +/- 0.5S, J2000 Z = 0.19 V = 16.7+/-1.4 DEC=+07D 43' 12.3" +/- 0.5" 2 QSO0814+425 GALAXY,BL Lac RA=08H 18M 16.0S +/- 0.5S, J2000 Z = V = 18.3+/-0.5 DEC=+42D 22' 45.4" +/- 0.5" 0.258 5938( 6) - 03/14/96 14:09 - [ 4] Visit: 01 Visit Requirements: SEQ 1-2 WITHIN 100M On Hold Comments: Additional Comments: Visits 1 and 2 MUST be consecutive Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 10S SEQuence 1-10 NON-INTerruptible SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 2 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 10S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 3 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 45S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 4 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 45S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 5 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 45S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 6 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 150S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 7 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 150S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 8 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 325S SAME POSition AS 1; SPLIT=NO Comments: This exp will cause target to bleed somewhat. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 9 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; SPLIT=NO Comments: This exp will cause target to bleed somewhat. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 10 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; END ORBIT; EXPAND; SPLIT=NO MAXimum DURation 1200S; Comments: This exp will cause target to bleed somewhat. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 5938( 6) - 03/14/96 14:09 - [ 5] Visit: 02 Visit Requirements: ORIENTation 20.0D TO 20.5D FROM 1; On Hold Comments: Additional Comments: Visits 1 and 2 MUST be consecutive Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 10S SEQuence 1-10 NON-INTerruptible SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 2 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 10S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 3 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 45S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 4 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 45S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 5 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 45S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 6 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 150S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 7 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 150S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 8 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 325S SAME POSition AS 1; SPLIT=NO Comments: This exp will cause target to bleed somewhat. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 9 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; SPLIT=NO Comments: This exp will cause target to bleed somewhat. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 10 PKS2254+074 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; END ORBIT; EXPAND; SPLIT=NO MAXimum DURation 1200S; Comments: This exp will cause target to bleed somewhat. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 5938( 6) - 03/14/96 14:09 - [ 6] Visit: 03 Visit Requirements: SEQ 3-4 WITHIN 100M On Hold Comments: Additional Comments: Visits 3 and 4 MUST be consecutive Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 30S SEQuence 1-6 NON-INTerruptible SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 30S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 4 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 5 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 550S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 6 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 525S SAME POSition AS 1; END ORBIT; EXPAND; SPLIT=NO MAXimum DURation 1200S; Comments: Target will saturate. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 5938( 6) - 03/14/96 14:09 - [ 7] Visit: 04 Visit Requirements: ORIENTation 20.0D TO 20.5D FROM 3; On Hold Comments: Additional Comments: Visits 3 and 4 MUST be consecutive Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 30S SEQuence 1-6 NON-INTerruptible SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 30S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 4 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 300S SAME POSition AS 1; SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 5 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 550S SAME POSition AS 1; SPLIT=NO Comments: Target will saturate. ------------------------------------------------------------------------------------------------------------------------------------ 6 QSO0814+425 WFPC2 IMAGE PC1-FIX F814W 7940 CLOCKS=NO,CR- 1 525S SAME POSition AS 1; END ORBIT; EXPAND; SPLIT=NO MAXimum DURation 1200S; Comments: Target will saturate. This is ok. ------------------------------------------------------------------------------------------------------------------------------------ 5938( 6) - 03/14/96 14:09 - [ 8] Summary Form for Proposal 5938 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CLOCKS=NO CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SEQ 1-2 WITHIN 100M SEQuence 1-10 NON-INTerruptible SAME POSition AS 1; SAME POSition AS 1; END ORBIT; EXPAND; MAXimum DURation 1200S; ORIENTation 20.0D TO 20.5D FROM 1; SEQ 3-4 WITHIN 100M SEQuence 1-6 NON-INTerruptible ORIENTation 20.0D TO 20.5D FROM 3; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PKS2254+074 QSO0814+425 ------------------------------------------------------------------------------------------------------------------------------------