6112( 5) - 01/17/96 12:14 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6112 Version: 5 Check-in Date: 17-Jan-1996 09:34:03 1.Proposal Title: UV-Bright LINERs and the AGN Connection ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dan Maoz Tel-Aviv University CoI: A. V. Filippenko University of California, Berkeley N CoI: Luis C. Ho University of California, Berkeley N CoI: Joseph C. Shields University of Arizona N CoI: A. Koratkar Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract We propose UV spectroscopy of two LINER galaxies displaying bright compact ultraviolet nuclear sources in HST FOC images. Together with two additional objects already being observed in Cycle 4, these are two of the four LINERs that were detected as nuclear UV sources in a complete sample of over 100 nearby galaxies imaged with HST. They may be the subgroup of LINERs in which the ionizing continuum is unobscured along our line of sight. As such, they are prime targets for studying the UV properties of LINERs and relating them to AGNs as a whole. We will measure the continuum shapes, emission-line fluxes and absorption-line features of UV-bright LINERs. With these measurements, we will discriminate between the excitation mechanisms that have been proposed for LINERs. In particular, we will test whether the observed UV sources are the weakest manifestation of the quasar phenomenon, or else a compact young stellar cluster. Placing LINERS (which exist in a large fraction of all galaxies) into, or removing them from the AGN zoo is important for understanding the nature of AGNs, their number and evolution, and their contribution to the X-ray background. Together with ASCA and ISO data and existing optical spectra, HST will provide for the first time a multiwavelength picture of a statistical sample of LINERs which will be instrumental for deciphering their nature. ------------------------------------------------------------------------------------ 6112( 5) - 01/17/96 12:14 - [ 2] Observations Description ------------------------ We will observe each of the two UV-bright LINERs through three FOS gratings, G130H, G190H, and G270H, in order to cover the 1150--3300 Angstrom range at 1-2 Angstrom (200-250 km/s) resolution. This will allow resolving and measuring line -widths for some of the emission lines, especially in the objects with broader lines. We will use the 0.86'' (1.0) circular aperture. Based on the FOC images, we know the sources are unresolved and the extended galaxy background negligible at UV wavelengths. The large aperture will therefore not degrade the spectral resolution. By using the 0.86'' aperture we will gain by maximizing the throughput, and by being able to switch to the FOS/RD for the G190H and G270H gratings to increase the efficiency without requiring a new peakup acquisition. At ~ 3200Angstrom, where the starlight from the underlying galaxy begins to dominate, the 0.86'' aperture will provide a fairly good match to our ground-based 1''-aperture optical spectra of these objects. Additional diffuse and point-sources which we have identified in the FOC images around the bright central sources are always >0.65'' away from the central sources, and so will be nicely excluded by the 0.43''-radius aperture. From our FOC data, we have accurate measurements of the broad-band (~ 2300Angstrom) UV flux in each of the LINERs, with f_Lambda(2270A) of (1 and 10) * 10^-15 erg s^-1cm^-2 A^-2 for NGC 5055 and NGC 4569, respectively. Assuming LINERs have a f_Nu\\propto nu^-1 continuum like other low-luminosity AGNs, we can obtain a good estimate of the expected flux. For NGC 5055 (Dec. +42) we have 54-minutes visibility per orbit, allowing an A+B1+D1 peakup acquisition in one orbit (12 min GS acquisition, + 42 min A+B1+D1 = 54 minutes). Allowing for 6 minutes reacq time and 7 minutes overhead time at the end of each of the next orbits, we will integrate in the G130H grating for the next three orbits, 41 minutes net integration time per orbit, and so obtain a SNR of ~ 10 per resolution element for the continuum in the 1200-- 1600 Angstrom range. This will allow us to measure the continuum shape and the strong emission and absorption lines in this range. We will then side-switch to the FOS red side, and use the fifth orbit for a 41-minute exposure in G190H (SNR~19) and the 6th orbit for a 41-minute exposure in G270H (SNR~30). For NGC 4569 (Dec. +13) we have 53 minutes visibility per orbit, requiring one orbit for GS acq (12 min) plus an A+B1 peakup (7+13 min), and a second orbit for GS reacq. (6 min) and D1 peakup (22 min), leaving 18 minutes integration time in G130H in the second orbit. The third orbit will be used for another 40 minutes net integration time through G130H, giving a total SNR~22. We will then side-switch to the FOS red side, and use the fourth orbit for a 22 -minute exposure in G190H (SNR~50) and an 11-minute exposure in G270H (SNR~50). This will allow us to and also search for weaker features in NGC 4569. The typical SNRs per resolution element we are presently aiming for (~ 10-20 in continuum, >10-20 in lines) will provide the best measurement to date of the UV spectrum of LINERs. We will consider requesting higher SNR data in future Cycles, pending the results of these observations. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6112( 5) - 01/17/96 12:14 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_address Ship Via: UPS Email: __Diagnostic-Sum-Section__ Software-Version (Contro, ------------------------------------------------------------------------------------ 6112( 5) - 01/17/96 12:14 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4569 GALAXY,SPIRAL,LINER RA=12H 36M 49.81S +/- 0.01S, 2000 V=-261 SURF(V) = 14.0+/-1.0 DEC=+13D 09' 45.8" +/- 0.1", F-CONT(2270)=1+/-0.2e-14 PLATE-ID=00IY Comments: Nuclear UV sources observed in the FOC 2 NGC5055 GALAXY,SPIRAL,LINER RA=13H 15M 49.27S +/- 0.01S, 2000 V=+503 SURF(V) = 14.0+/-1.0 DEC=+42D 01' 46.3" +/- 0.1", F-CONT(2270)=1+/-0.2e-15 PLATE-ID=01PY Comments: Nuclear UV sources observed in the FOC 6112( 5) - 01/17/96 12:14 - [ 5] 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 NGC4569 FOS/BL ACQ/PEA 4.3 MIRROR SCAN-STEP- 1 3S ONBOARD ACQ FOR 2 K Y=1.2,SEARCH- SIZE-X=1,SEARCH -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4569 FOS/BL ACQ/PEA 1.0 MIRROR SCAN-STEP- 1 5S ONBOARD ACQ FOR 3 K X=0.61,SCAN- STEP- Y=0.61,SEARCH- SIZE-X=6,SEARCH Comments: -SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4569 FOS/BL ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 8S ONBOARD ACQ FOR 4-6 K X=0.17,SCAN- STEP- Y=0.17,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4569 FOS/BL ACCUM 1.0 G130H 1 50M EXPAND MAX DUR 300% ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC4569 FOS/RD ACCUM 1.0 G190H 1 22M EXPAND MAX DUR 300% ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC4569 FOS/RD ACCUM 1.0 G270H 1 11M EXPAND MAX DUR 300% ------------------------------------------------------------------------------------------------------------------------------------ 6112( 5) - 01/17/96 12:14 - [ 6] 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 NGC5055 FOS/BL ACQ/PEA 4.3 MIRROR SCAN-STEP- 1 10S ONBOARD ACQ FOR 2 K Y=1.2,SEARCH- SIZE-X=1,SEARCH -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC5055 FOS/BL ACQ/PEA 1.0 MIRROR SCAN-STEP- 1 10S ONBOARD ACQ FOR 3 K X=0.61,SCAN- STEP- Y=0.61,SEARCH- SIZE-X=6,SEARCH Comments: -SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC5055 FOS/BL ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 10S ONBOARD ACQ FOR 4-6 K X=0.17,SCAN- STEP- Y=0.17,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC5055 FOS/BL ACCUM 1.0 G130H 1 123M END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC5055 FOS/RD ACCUM 1.0 G270H 1 35M END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC5055 FOS/RD ACCUM 1.0 G190H 1 41M END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 6112( 5) - 01/17/96 12:14 - [ 7] Summary Form for Proposal 6112 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-Y=1.2 SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SEARCH-SIZE-Y=2 SEARCH-SIZE-Y=5 SEARCH-SIZE-X=6 SEARCH-SIZE-X=5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4-6 EXPAND MAX DUR 300% END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G130H G190H G270H ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC4569 NGC5055 ------------------------------------------------------------------------------------------------------------------------------------