6002( 9) - 10/17/96 19:32 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6002 Version: 9 Check-in Date: 17-Oct-1996 19:30:21 1.Proposal Title: Spectroscopy of the Rapidly Rotating Nuclear Disk in the Virgo S0 NGC4526 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. Vera Rubin CARENEGIE INSTITUTION CoI: Dr. Bryan Miller Department of Terrestrial Magnetism, N Carnegie Institution of Washington CoI: Dr. Brad Whitmore Space Telescope Science Institute N CoI: Dr. Holland Ford Johns Hopkins University N CoI: Laura Ferrarese Johns Hopkins University N ------------------------------------------------------------------------------------ 6. Abstract Ground-based spectroscopic observations of 100 galaxies in the Virgo cluster by Rubin and Kenney reveal that 25 percent of the galaxies have rapidly rotating distinct nuclear gas disks. These galaxies span Hubble types E to Sc, and are located throughout the cluster. Seven of them have been imaged by WFPC2. Of all, NGC 4526 (S0) is the most spectacular. A rapidly rotating nuclear disk of gas, dust, and stars extends from the nucleus to 15'', 7 percent of the galaxy radius; gas is not observed beyond. Within a few arcseconds of the nucleus, rotation velocities surpass 250 km/s and a mass greater than 10^9Msun is derived, but these values are surely degraded by the 1.5'' ground-based spatial resolution. We propose to study the morphology and dynamics of the nuclear region of NGC 4526 by using WFPC2 narrow band images, in order to isolate the H Alpha+NII region, and with FOS spectra, covering the wavelength region from H-beta through SII6731 Angstrom. Because we are interested in studying phenomena taking place on scales of a fraction of an arcsec, the high spatial resolution of HST is required. ------------------------------------------------------------------------------------ Observations Description ------------------------ Imaging - In order to obtain the highest resolution, the nucleus of NGC 4526 will be centered in the PC1. The WFPC2 will be used with filters F658N (H Alpha+NII) and F547M to obtain an on-line and off-line image of NGC 4526. We will use our Cycle 4 F814W image with the new F547M image to estimate color corrections and to permit accurate subtraction of the stellar continuum. To facilitate subtraction of off-band images from the on-band image, we request that all exposures be taken with the same pointing. Multiple exposures will permit cosmic ray rejection. One of the H-Alpha images is dithred 11 PC pixels (0.50 ", which is also 5 WF pixels) in order to help remove hot pixels. 1) Exposure Time Calculation, From our WFPC2 F555W image of NGC 4526, the surface brightness at the center is 14.5 V mag arcsec^-2. We have calculated that an exposure time of 600 seconds will produce a S/N of at least 10 at 10 arcsec from the center through filter F547M. For the H Alpha image, we adopt an exposure time of 3600 seconds. Spectroscopy - We propose to use the 0.3 arcsec aperture and the G570H grating to obtain spectra at the nuclear position and at two additional off-nuclear positions. We plan to obtain two spectra along the major axis of the galaxy, located 0.20" (slighty less than one aperture width) on either side of the nucleus. Exposure Time Calculation - From our HST V band (F547W) and Halpha (F658N) images of NGC 4526, we calculated that a 2810 second exposure for the nuclear position, and 7230 second exposures for the major axis positions are needed. Target Acquisition - Our current plan is to use a 16.6 magnitude star located near the major axis at a nuclear distance of 19.7 arcsec, which would allow us to perform a binary acquisition plus a two stage peakup on the star, and subsequently slew to the nucleus of NGC 4526 and perform one additional peakup. Misc. - A wavelength calibration has been added at the end of each orbit. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6002( 9) - 10/17/96 19:32 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4526 GALAXY RA=12H 34M 03.103S +/- .02S, 2000 V=450 V = 9.58+/-0.06 DEC=7D 41' 57.512" +/- 0.3" B-V = 0.95+/-0.06 Comments: Coordinates from Cycle 4 WFPC2 observations. 2 NGC4526-OFF STAR RA-OFF=-1.239S +/- 0.003S, DEC- 2000 V = 16.6+/-0.1 OFF=+6.708" +/- 0.05", FROM 5 V-I = 0.9 Comments: Coordinates from Cycle 4 WFPC2 observations. 3 NGC4526-POS1 GALAXY RA-OFF=+0.012S +/- 0.001S, DEC- 2000 V=450 V = 9.58+/-0.06 OFF=-0.074" +/- 0.001", FROM 5 B-V = 0.95+/-0.06 4 NGC4526-POS2 GALAXY RA-OFF=-0.012S +/- 0.001S, DEC- 2000 V=450 V = 9.58+/-0.06 OFF=+0.074" +/- 0.001", FROM 5 B-V = 0.95+/-0.06 5 NGC4526-REV GALAXY RA=12H 34M 03.103S +/- .02S, 2000 V=450 V = 9.58+/-0.06 DEC=7D 41' 57.512" +/- 0.3", B-V = 0.95+/-0.06 PLATE-ID=01UQ Comments: Coordinates from Cycle 4 WFPC2 observations. 6002( 9) - 10/17/96 19:32 - [ 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 NGC4526 WFPC2 IMAGE PC1 F547M CR-SPLIT=NO 2 300 S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4526 WFPC2 IMAGE PC1 F658N CR-SPLIT=NO 1 1100 S POS TARG +0.50, +0.50 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4526 WFPC2 IMAGE PC1 F658N CR-SPLIT=NO 2 1200 S ------------------------------------------------------------------------------------------------------------------------------------ 6002( 9) - 10/17/96 19:32 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC4526-OFF FOS/RD ACQ/BIN 4.3 MIRROR BRIGHT=132000,FAINT=330 1 17.0 S ONBOARD ACQ FOR 45-75 ARY Comments: BINARY ACQUISITION ON OFFSET STAR ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC4526-OFF FOS/RD ACQ/PEA 0.5 MIRROR SCAN-STEP-X=0.29,SCAN-STEP-Y=0.29 1 2.5 S ONBOARD ACQ FOR 45-75 K ,SEARCH-SIZE-X=3,SEARCH-SIZE-Y=3 Comments: PEAK-UP ON OFFSET STAR ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC4526-OFF FOS/RD ACQ/PEA 0.3 MIRROR SCAN-STEP-X=0.17,SCAN-STEP-Y=0.17 1 2.5 S ONBOARD ACQ FOR 45-75 K ,SEARCH-SIZE-X=3,SEARCH-SIZE-Y=3 Comments: PEAK-UP ON OFFSET STAR ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC4526-REV FOS/RD ACQ/PEA 0.3 G570H 6470-66 SCAN-STEP-X=0.052, 1 60.0 S ONBOARD ACQ FOR 45-75 K 70 SCAN-STEP-Y=0.052,SEARCH-SIZE-X=5 ,SEARCH-SIZE-Y=5 Comments: CRITICAL PEAK-UP ON NUCLEUS ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE FOS/RD ACCUM 0.3 G570H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC4526-REV FOS/RD ACCUM 0.3 G570H 1 2800 S ------------------------------------------------------------------------------------------------------------------------------------ 55 WAVE FOS/RD ACCUM 0.3 G570H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 60 NGC4526-POS FOS/RD ACCUM 0.3 G570H 1 7230 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 65 WAVE FOS/RD ACCUM 0.3 G570H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 70 NGC4526-POS FOS/RD ACCUM 0.3 G570H 1 7230 S 2 ------------------------------------------------------------------------------------------------------------------------------------ 75 WAVE FOS/RD ACCUM 0.3 G570H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 6002( 9) - 10/17/96 19:32 - [ 4] Summary Form for Proposal 6002 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ/BINARY ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO FAINT=330 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG +0.50, +0.50 ONBOARD ACQ FOR 45-75 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F547M F658N MIRROR G570H ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC4526 NGC4526-OFF NGC4526-REV WAVE NGC4526-POS1 NGC4526-POS2 ------------------------------------------------------------------------------------------------------------------------------------