6532( 4) - 10/24/96 14:13 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6532 Version: 4 Check-in Date: 24-Oct-1996 14:10:16 1.Proposal Title: A Definitive Test for the Excitation Mechanism of LINERs ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle GALAXIES & CLUSTERS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Michael A. Dopita MT. STROMLO & SIDING SPRINGS OBS CoI: Elaine Sadler Dept.\\\\ of Physics, U.\\\\ of Sydney N CoI: Ralph Sutherland JILA, University of Colorado N CoI: Geoffrey Bicknell Mt.\\\\ Stromlo and Siding Spring N Observatories CoI: Ian Evans Space Telescope Science Institute N CoI: John Hawley Virginia Institute for Theoretical N Astronomy, U.\\\\ of Virginia CoI: Anuradha Koratkar Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract We propose to develop our definitive test which will determine whether LINERs are photoionized or shock ionized, by obtaining 1150--6800 Angstrom FOS spectra of two bright, nearby and unreddened LINER gas disks in the spiral galaxy M81 (NGC 3031) and in the elliptical galaxy NGC 1052. At visible wavelengths, the emission-line diagnostics which might distinguish between excitation mechanisms are ambiguous. However, models generated using our shock and photoionization code MAPPINGS II, shows that a comparison between the optical and UV line intensities provides an unambiguous diagnostic. The shock produces a strong UV emission-line spectrum, while the photoionization mechanism does not. In Cycle 5, we were able to show that the LINER disk in the nucleus of M87 is indeed shock excited, and that the pre-shock gas has an equipartition magnetic field. However, M87 may not be a ``typical'' LINERNull. In this cycle we are seeking time to test the model on prototypical LINER nuclei, one in an elliptical, and the other in a spiral host galaxy. If these also prove to be excited by magnetohydrodynamic shocks, this would provide a powerful new insight into the accretion process of AGN, and open up the way for a quantitative understanding of the LINER phenomenon. ------------------------------------------------------------------------------------ Observations Description ------------------------ In Cycle 6 we propose to obtain a complete, high quality spectrum of the nuclear regions of two bright LINER accretion disks, using the 0.86 arcsecond square aperture of FOS. We would obtain FOS/BL spectrophotometry in the range 1150--4500 Angstrom using the G160L grating and the Prism, and FOS/RD spectrophotometry in the range 2220--6740 Angstrom using the G270H, G400H, and G570H gratings. The optical spectra are necessary to properly normalize the UV spectra to the optical. In the optical we aim to achieve a sensitivity which is sufficient to detect lines as faint as 5\\\\% of HBetaNull. In the UV, such high sensitivity is not necessary, since either the lines are either comparable in intensity to HBeta, or else they are absent. We therefore aim to achieve a sensitivity of 10\\\\% of HBeta at 2200 AngstromNull. The FOS/BL Prism observation is needed to ensure reliable calibration between the FOS/BL and the FOS/RD observations, and the G160L grating has been selected as an optimum compromise between sensitivity and resolution in the UVNull. For efficiency, the side switch between FOS/BL and FOS/RD would be carried out during earth occultation. The exposure times are estimated from the counts diode^-1,s^-1 (C) through the 0.86'' aperture given by the estimated continuum fluxes ( erg,cm^-2 s^-1 Angstrom^-1) by the following formula derived from the instrument handbook: \\\\log C = \\\\log F(Lambda) + A, where the Lambda, A pairs used are 1550Angstrom, 14.02 (G160L), 2300Angstrom, 14.78 (PRISM), 2300Angstrom, 14.73 (G270H), 4850Angstrom, 15.12 (G400H), and 4850Angstrom, 15.37 (G570H). For M81 the peak HBeta line flux is rm~\\\\.4.5*10^-15 erg cm^-2 Angstrom^-1 arcsec^-2 s^-1 (estimated from HGamma; FOS IDT), while for NGC 1052 it is rm~\\\\.2*10^- 15 erg cm^-2 Angstrom^-1 arcsec^-2 s^-1 (Fosbury et al.\\\\ 1978). For both objects, the HBeta emission -line is observed against a continuum flux rm~\\\\.2*10^-15 erg cm^-2 Angstrom^-1 arcsec^-2 s^-1, and the reddening is low in each case. For M81, to reach the required sensitivities, we require 1 orbit for the combined G160L and Prism exposures with FOS/BL, one orbit for the combined G270H, G400H, and G570H exposures with FOS/RD, and one additional orbit for target acquisition (we assume that the acquisition will occur using the red detector, and that a side switch to the blue detector will occur in Earth occultation). For NGC 1052, 3 orbits are required for the FOS/BL observations, 2 orbits for the FOS/RD observations, and one additional orbit for target acquisition (with the same assumptions as for M81). Real Time Justification ----------------------- For the FOS spectrophotometry to be used as input to modeling codes, all the observations for each target need to be obtained during a single visit. The side switch would be scheduled during earth occultation. The proposed observation is entirely self-contained. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6532( 4) - 10/24/96 14:13 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1052 GALAXY, ELLIPTICAL, RA=02H 41M 4.6992S +/- 0.4", J2000 V = 16.0 LINER DEC=-08D 15' 20.8485" +/- 0.3", F-LINE(4686)=2+/-0.5e-15 PLATE-ID=00DW F-CONT(4000)=2+/-1e-15 Comments: Note that the guide star 5285-507 is a double and should NOT be used for pointing purposes. 2 NGC3031 GALAXY, ELLIPTICAL, RA=09H 55M 33.3763S +/- 0.3", J2000 V = 16.0 LINER DEC=69D 03' 55.161" +/- 0.3", F-LINE(4686)=4.5+/-0.5e-15 PLATE-ID=00M9 F-CONT(4000)=2+/-1e-15 Comments: Note that the guide star 4383-328 is a non-star. Please make sure it is turned off. 6532( 4) - 10/24/96 14:13 - [ 2] 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1052 FOS/BL ACQ/PEA 4.3 MIRROR SEARCH-SIZE-X=1,SEARCH-SIZE-Y=3, 1 8 S ONBOARD ACQ FOR 2 K SCAN-STEP-Y=1.23 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1052 FOS/BL ACQ/PEA 1.0-PAI MIRROR SEARCH-SIZE-X=6,SEARCH-SIZE-Y=2, 1 8 S ONBOARD ACQ FOR 3 K R-A SCAN-STEP-X=0.61,SCAN-STEP-Y=0.61 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1052 FOS/BL ACQ/PEA 0.25-PA MIRROR SEARCH-SIZE-X=5,SEARCH-SIZE-Y=5, 1 9 S ONBOARD ACQ FOR 4-8 K IR-A SCAN-STEP-X=0.17,SCAN-STEP-Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC1052 FOS/BL ACCUM 1.0-PAI PRISM STEP-PATT=SINGLE 1 600 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC1052 FOS/BL ACCUM 1.0-PAI G160L STEP-PATT=SINGLE 1 6780 S MAX DUR 200% R-A Comments: Note that this exposure is splitting incorrectly. It needs to be fixed. The G160L exposure + the Prism exposure should be a total of 3 orbits with the Prism exposure no more than 800S. ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC1052 FOS/RD ACCUM 1.0-PAI G270H STEP-PATT=SINGLE 1 2400 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC1052 FOS/RD ACCUM 1.0-PAI G400H STEP-PATT=SINGLE 1 1200 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC1052 FOS/RD ACCUM 1.0-PAI G570H STEP-PATT=SINGLE 1 800 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 6532( 4) - 10/24/96 14:13 - [ 3] Visit: 02 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3031 FOS/BL ACQ/PEA 4.3 MIRROR SEARCH-SIZE-X=1,SEARCH-SIZE-Y=3, 1 9 S ONBOARD ACQ FOR 2 K SCAN-STEP-Y=1.23 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3031 FOS/BL ACQ/PEA 1.0-PAI MIRROR SEARCH-SIZE-X=6,SEARCH-SIZE-Y=2, 1 9 S ONBOARD ACQ FOR 3 K R-A SCAN-STEP-X=0.61,SCAN-STEP-Y=0.61 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3031 FOS/BL ACQ/PEA 0.25-PA MIRROR SEARCH-SIZE-X=5,SEARCH-SIZE-Y=5, 1 10 S ONBOARD ACQ FOR 4-8 K IR-A SCAN-STEP-X=0.17,SCAN-STEP-Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3031 FOS/BL ACCUM 1.0-PAI G160L STEP-PATT=SINGLE 1 2000 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3031 FOS/BL ACCUM 1.0-PAI PRISM STEP-PATT=SINGLE 1 240 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC3031 FOS/RD ACCUM 1.0-PAI G270H STEP-PATT=SINGLE 1 1000 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC3031 FOS/RD ACCUM 1.0-PAI G400H STEP-PATT=SINGLE 1 400 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC3031 FOS/RD ACCUM 1.0-PAI G570H STEP-PATT=SINGLE 1 300 S MAX DUR 200% R-A ------------------------------------------------------------------------------------------------------------------------------------ 6532( 4) - 10/24/96 14:13 - [ 4] Summary Form for Proposal 6532 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP-Y=1.23 SCAN-STEP-Y=0.61 SCAN-STEP-Y=0.17 STEP-PATT=SINGLE SCAN-STEP-X=0.61 SCAN-STEP-X=0.17 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4-8 MAX DUR 200% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR PRISM G160L G270H G400H G570H ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1052 NGC3031 ------------------------------------------------------------------------------------------------------------------------------------