6108( 7) - 05/21/96 10:34 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6108 Version: 7 Check-in Date: 21-May-1996 10:29:42 1.Proposal Title: NGC 3516: A Critical Test-case for AGN Absorption and Emission Line Regions ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Anuradha Koratkar Space Telescope Science Institute CoI: Paul O'Brien Oxford University N CoI: Kirk Korista University of Kentucky N CoI: David Axon Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract A significant number of AGN display intrinsic, broad, blueshifted UV absorption lines thought to arise from gas located close to the powerful central engine. The origin and physical properties of the absorbing gas are not well understood, but the absorbing gas has a clear advantage over the emission line gas in that it provides a probe of the nucleus along a well defined line-of-sight. As Seyfert 1 galaxies are believed to be the low luminosity analogues of QSOs, these low luminosity AGN provide a critical comparison source for stringent testing of AGN models. Based on IUE data, NGC 3516 has the strongest (largest equivalent-width) and most variable UV absorption line spectrum of any known Seyfert 1 galaxy. An extensive monitoring campaign of NGC 3516 showed that most of the important diagnostic broad absorption lines were undetectable with IUE. Therefore, we propose UV spectrophotometric monitoring of NGC 3516 with the HST/FOS, in order to conduct a detailed, simultaneous, high signal-to-noise ratio study of the highly variable absorption features which are associated with numerous ionic species. Analysis of the variable absorption line spectrum will constrain the location, density, column density, ionization parameter and velocity structure of the absorbing gas. High quality data on several ionic species will also constrain the broad emission line gas, and in particular the possible influence of a beamed ionizing continuum source which the previous IUE data suggest may affect the emission line cores. ------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 2] Observations Description ------------------------ Using the HST/FOS will yield a threefold advantage compared to IUE: First, the much higher signal-to-noise in the FOS spectra will enable us to search for absorption from several ionic species with lower column densities than is achievable with IUE (e.g. C III Lambda 1176 and Mg II Lambda 2800). Second, the higher spectral resolution of the observations of the line profiles will provide improved limits as to the column density and density of the absorbing gas, and therefore better define its distance from the central source. Third, the higher spatial resolution resulting from the smaller FOS aperture size (we will use the 1 arcsecond circular aperture) will significantly reduce contamination by stellar continua from the surrounding galaxy at the long wavelengths, and will also reduce the influence of geocoronal emission at short wavelengths. We will observe the nucleus of NGC 3516 using the G130H, G190H and G270H gratings of the FOS, to cover the spectral range 1150 to 3300 Angstrom\\ at 2Angstrom\\ resolution. We will acquire the target using an ACQ/BINARY. The target acquisition will be followed by a 22 minute exposure in the G190H grating and a 4 minute exposure in the G270H grating, giving a signal-to-noise per diode at 1600Angstrom\\ and 2800Angstrom\\ of ~25. We will then switch to the blue detector and observe with the G130H grating for 100 minutes, giving a signal-to-noise per diode at 1400Angstrom\\ of ~20. This observing strategy requires a total of 3 orbits per visit. The exposure time calculations assume a UV continuum flux of 1.5 * 10^-14 erg cm^-2 s^-1 AA^ -1 (the average UV flux observed by IUE before the 1993 campaign, although this object is variable). Based on the historic UV continuum light curve, we request a visit approximately every 60 days for a period of 300 days to sample the continuum flux range. This gives a total of 15 orbits spread over 5 visits. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- The exact spacing between the visits is not critical, but a 60 day interval is a good compromise between the observed variability timescale and the amount of available space-craft time. We note that NGC 3516 is on occasion in a continuous viewing zone which could be taken advantage of for scheduling efficiency purposes. The data will be reduced using the standard FOS pipeline processing and standard packages such as IRAF/STSDAS. We have generated line profile analysis techniques during our IUE data reduction which will be adapted and used for the FOS data. All the investigators in this project have experience with analyzing variability data. Korista and Koratkar were deeply involved with the NGC 5548 campaign utilizing the FOS, and therefore have a lot of experience with FOS data analysis. ------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3516 GALAXY, SEYFERT, RA=11H 06M 47.55S +/- 1.0", J2000 Z=0.009 V = 12.5 LENTICULAR DEC=72D 34' 6.9" +/- 1.0", PLATE F-CONT(1300)=4+/-2e-14 -ID=01L3 F-CONT(2350)=2+/-1e-14 Comments: Highly variable Seyfert galaxy. Has varied in the UV by a factor of 4 in the last 5 years. The UV spectrum is much flatter than the nu^-1 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1984.026 0.0 0.0 0.0 6108( 7) - 05/21/96 10:34 - [ 5] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: The 5 visits are to be separated by approximately 60 days. The object may sometimes be in CVZ and during these visits the exposures should be extended to fill the orbits. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3516 FOS/BL ACQ/BIN 4.3 MIRROR 1 5S ONBOARD ACQ FOR 2-4 ARY ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3516 FOS/BL ACCUM 1.0 G130H 1 4720S MAX DUR 300% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3516 FOS/RD ACCUM 1.0 G190H 1 1320S MAX DUR 200% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3516 FOS/RD ACCUM 1.0 G270H 1 360S MAX DUR 100% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 6] Visit: 02 Visit Requirements: AFTER 1 BY 50D TO 75D On Hold Comments: Additional Comments: The 5 visits are to be separated by approximately 60 days. The object may sometimes be in CVZ and during these visits the exposures should be extended to fill the orbits. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3516 FOS/BL ACQ/BIN 4.3 MIRROR 1 5S ONBOARD ACQ FOR 2-4 ARY ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3516 FOS/BL ACCUM 1.0 G130H 1 3900S MAX DUR 300% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3516 FOS/BL ACCUM 1.0 G160L 1 360S MAX DUR END ORBIT Comments: We introduce the G160L grating observation to help align the red and blue observations since accurate flux calibartion is important for the proposed science. Note that the defect in the G160L is not important to the present analysis. ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3516 FOS/RD ACCUM 1.0 G190H 1 22M MAX DUR 200% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3516 FOS/RD ACCUM 1.0 G270H 1 360S MAX DUR 100% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 7] Visit: 03 Visit Requirements: AFTER 2 BY 50D TO 75D On Hold Comments: Additional Comments: The 5 visits are to be separated by approximately 60 days. The object may sometimes be in CVZ and during these visits the exposures should be extended to fill the orbits. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3516 FOS/BL ACQ/BIN 4.3 MIRROR 1 5S ONBOARD ACQ FOR 2-4 ARY ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3516 FOS/BL ACCUM 1.0 G130H 1 3900S MAX DUR 300% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3516 FOS/BL ACCUM 1.0 G160L 1 360S MAX DUR END ORBIT Comments: We introduce the G160L grating observation to help align the red and blue observations since accurate flux calibartion is important for the proposed science. Note that the defect in the G160L is not important to the present analysis. ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3516 FOS/RD ACCUM 1.0 G190H 1 22M MAX DUR 200% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3516 FOS/RD ACCUM 1.0 G270H 1 360S MAX DUR 100% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 8] Visit: 04 Visit Requirements: AFTER 20-SEP-96 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 NGC3516 FOS/BL ACQ/BIN 4.3 MIRROR 1 5S ONBOARD ACQ FOR 2-4 ARY ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3516 FOS/BL ACCUM 1.0 G130H 1 3900S MAX DUR 300% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3516 FOS/BL ACCUM 1.0 G160L 1 360S MAX DUR END ORBIT Comments: We introduce the G160L grating observation to help align the red and blue observations since accurate flux calibartion is important for the proposed science. Note that the defect in the G160L is not important to the present analysis. ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3516 FOS/RD ACCUM 1.0 G190H 1 22M MAX DUR 200% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3516 FOS/RD ACCUM 1.0 G270H 1 360S MAX DUR 100% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 9] Visit: 05 Visit Requirements: BETWEEN 15-JUL-96 AND 25-AUG-96 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 NGC3516 FOS/BL ACQ/BIN 4.3 MIRROR 1 5S ONBOARD ACQ FOR 2-4 ARY ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3516 FOS/BL ACCUM 1.0 G130H 1 3900S MAX DUR 300% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3516 FOS/BL ACCUM 1.0 G160L 1 360S MAX DUR END ORBIT Comments: We introduce the G160L grating observation to help align the red and blue observations since accurate flux calibartion is important for the proposed science. Note that the defect in the G160L is not important to the present analysis. ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3516 FOS/RD ACCUM 1.0 G190H 1 22M MAX DUR 200% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3516 FOS/RD ACCUM 1.0 G270H 1 360S MAX DUR 100% Comments: Fill orbit if object in CVZ for this exposure. ------------------------------------------------------------------------------------------------------------------------------------ 6108( 7) - 05/21/96 10:34 - [ 10] Summary Form for Proposal 6108 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2-4 MAX DUR 300% MAX DUR 200% MAX DUR 100% AFTER 1 BY 50D TO 75D MAX DUR END ORBIT AFTER 2 BY 50D TO 75D AFTER 20-SEP-96 BETWEEN 15-JUL-96 AND 25-AUG-96 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G130H G190H G270H G160L ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3516 ------------------------------------------------------------------------------------------------------------------------------------