7403( 9) - 08/24/99 09:52 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7403 Version: 9 Check-in Date: 24-Aug-1999 09:51:08 1.Proposal Title: Measuring Black Hole Masses in Broad- Lined AGNs ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Alex Filippenko University of California - Berkeley CoI: Aaron Barth University of California, Berkeley Y CoI: Luis Ho Center for Astrophysics N CoI: Hans-Walter Rix University of Arizona N CoI: Wallace Sargent California Institute of Technology N ------------------------------------------------------------------------------------ 5. Abstract Broad emission lines in AGNs are considered one of the most direct signatures of a large central mass, which is presumed to be a black hole. However, the black hole mass has been measured dynamically for only one broad-lined AGN, NGC 4258. We propose STIS and WFPC2 observations with which we will attempt to determine the central masses of 6 nearby broad- lined AGNs. Our sample is selected from the Palomar Observatory Dwarf Seyfert Survey, and we have chosen galaxies which show unusually steep nuclear rotation curves in order to maximize our chances of success. For these 6 galaxies, we propose to obtain STIS long-slit spectroscopy with the G750M grating of the [NII]-HAlpha wavelength region at five parallel slit positions covering the nuclear region. We will use the resulting two-dimensional velocity map to test for circular rotation and to measure dynamical masses at sub-arcsecond scales where a supermassive black hole may dominate the gravitational potential. We also r eq uest narrow-band and broad-band WFPC2 images of two of our galaxies to search for morphological evidence for ionized gas disks such as those discovered by HST in M87 and NGC 4261, and to assess the contribution of normal stars to the gravitational potential. The other four galaxies have suitable WFPC2 observations available or pending, and for these we will use the archival data. ------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 2] Observations Description ------------------------ As described above, the WFPC2 F547M and F658N images are essential components of our program; however, four of our target galaxies have WFPC2 HAlpha images pending, and for these we will analyze the archival data. For the two galaxies with no previous or planned WFPC2 F658N images (NGC 3227 and NGC 3245), we request a single orbit per galaxy for the WFPC2 imaging. For NGC 3227, this orbit will be used to obtain F658N and F547M images. For NGC 3245, an image through the F547M filter is planned. In addition to the F658N image, we request an exposure with the F702W filter in order to perform a continuum subtraction in case the archival F547M exposure is not yet available. (The method for performing continuum subtraction on HAlpha images using R-band exposures is described by Waller 1990.) We request that these images be taken in early- acquisition mode, in order to assist in our choice of position angle for the STIS slit. NGC 1052, 4036, 4278, and 4579 have narrow-band F658 N WFPC2 images pending. For these galaxies, we will not request any additional new WFPC2 data. During the STIS visits to these targets, we will request a brief STIS/CCD image through the F28X50LP filter, to ensure that we have some imaging data with sufficient signal-to-noise ratio (S/N) to measure the distribution of continuum light at the nucleus. (F28X50LP is a long-pass filter with a passband extending from 5500 to ~10000 Angstrom, covering the R and I bands. Since its sensitivity peaks near 6500 Angstrom, F28X50LP can be used for a rough continuum subtraction of the narrow-band data if necessary.) This STIS imaging-mode exposure is particularly important for NGC 1052, since there is a WFPC2 F658N exposure pending but no suitable post-refurbishment broad-band image. We request the following STIS configuration for our spectroscopic exposures. HAlpha and [NII] 6584 will be the brightest optical emission lines. By using the G750M grating (with the STIS CCD detector) in t he secondary tilt setting covering 6295--6867 Angstrom, our o bservations will cover the desired spectral range and also include ionO1 Lambda6300 and the [SII] doublet at 6717, 6731. We request G750M rather than G750L because the 500 km s^-1 spectral resolution of the G750L grating is insufficient for measuring precise rotation curves. The 0arcs2-wide slit offers a good compromise between throughput and spatial and spectral resolution, and we choose it for our observations. Target acquisitions will include a standard CCD acquisition plus a CCD peakup, which is required for proper centering in the 0arcs2 slit. As recommended in the STIS manual, we will use the F28X50LP filter for the acquisition images. Estimation of required exposure time for WFPC2 and STIS. It is difficult to estimate the S/N that we will obtain in an exposure of given duration, because the distributions of both line emission and starlight are unknown at HST resolution for our targets. Therefore, we must make some plausible assumptions about the distribution of t he ionized gas and starlight in the inner regions of the galaxies. Lacking more detailed information, we make the conservative assumption that 20 percent of the emission-line luminosity in the 2"x4" Palomar aperture comes from the central arcsecond. We also assume that the stellar continuum in the inner arcsecond has a surface brightness similar to those of galaxies of similar Hubble type found in the literature (e.g., Lauer et al 1996); a typical value is 15 mag arcsec^-2. With the resulting ``best-guess'' values for the average emission-line and continuum surface brightness within the central arcsecond, we can perform trial calculations with the online exposure time calculators. As an example for WFPC2, for NGC 3245 (the fainter of the two galaxies we will be imaging with WFPC2), we find that we should be able to obtain a S/N of at least 4 per pixel in the inner arcsecond of the continuum-subtracted Halpha+[NII] image with at least two 900-second exposures. For the spectro sc opic exposures, our main criterion is that we wish to be ab le to measure accurate wavelengths for HAlpha and/or [NII] 6583 (depending on which line is stronger) for each spatial resolution element; a S/N of >~15-20 in the emission line, per spatial resolution element, should suffice. We have constructed model spectra as inputs to the STIS exposure time calculator, with emission-line and continuum strengths as described above. Since much of the width of the emission lines in the ground-based spectra appears to come from rotation in these galaxies, the intrisic widths are likely to be smaller at high spatial resolution, and we have used widths of 100 km s^-1 in our test calculations. Using the STIS exposure calculator, we have computed the time required to reach our S/N target per spatial resolution element in the emission line, including the noise due to the stellar continuum as well as the detector readout noise. We find that we can reach S/N ~15-20 in exposure times of ~60 minutes per slit position for NGC 3245 and NGC 4036, th e targets with the faintest emission lines. For the brighter targets, total exposure times per slit position of ~40 minutes (NGC 4278 and NGC 4579) and ~20- 30 minutes (NGC 1052 and NGC 3227) should suffice. These exposure times are computed for off-nuclear pixels, not for the nucleus itself. Since all of our slit positions will sample a similar range of off-nuclear surface brightnesses, we choose equal exposure times for all slit positions. Assuming a total visibility of 53 minutes per orbit and after counting all required overheads including target acquisition, there will be time for two 20-minute exposures per orbit. We request the following number of orbits per galaxy for the STIS spectroscopy: eight orbits each for NGC 3245 and NGC 4036; six orbits each for NGC 4278 and NGC 4579; four orbits for NGC 1052; and three orbits for NGC 3227. We have included in our orbit calculations the additional time required for two wavelength calibrations per orbit (at 1.5 minutes ea ch ) in order to ensure the best possible wavelength scale. ( If on- orbit tests show the wavelength scale to be sufficiently stable, we may reduce this request to the standard 1 wavecal exposure per orbit, but we prefer 2 wavecals per orbit if there is any possibility of wavelength shift during an orbit.) We have also budgeted time for a brief (~1 minute) STIS/CCD imaging exposure through the F28X50LP filter. A sample visit for NGC 3227 (3 orbits total) would proceed as follows: ( CRSPLIT=2 is assumed for all exposures.) noindent Orbit 1--- Target acquisition and peakup at the nucleus. One 20 minute G750M exposure at nucleus. noindent Orbit 2--- Offset perpendicular to slit by +0arcs25. One 20-minute G750M exposure. Offset by an additional +0arcs25, and one more 20-minute G750M exposure. noindent Orbit 3--- Offset perpendicular to slit by--0arcs75. One 20-minute G750M exposure. Offset by an additional -- 0arcs25, and one more 20-minute G750M exposure. For galaxies which require longer exposure times per slit position, we will simp ly increase the number of exposures at each slit position, keeping the same basic pattern. We will use CRSPLIT=2 to facilitate cosmic-ray removal; for the galaxies requiring the longest exposures, we will obtain 3 sub-exposures per slit position. Real Time Justification ----------------------- None. In order to determine the kinematic major axis near the nucleus, we will obtain long-slit spectra of our target galaxies at 1--2 position angles at Lick Observatory. (We already have spectra at 1 or 2 position angles for each galaxy from the Palomar survey.) We will use the results, along with the WFPC2 early- acquisition or archival data, to decide on the position angle of the STIS slit for each galaxy. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 3] Data Distribution Paper Products: Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1052 GALAXY, ELLIPTICAL, RA=02H 41M 4.74S +/- 2", DEC=- J2000 V = 1470 SURF(V) = 14.5+/-0.3 LINER, NUCLEUS 08D 15' 22.0" +/- 2", PLATE- ID=00DW Comments: Peak central surface brightness measured from a WFPC1/PC F555W image. 2 NGC3227 GALAXY, SPIRAL, RA=10H 23M 30.573S +/- 0.5", J2000 V = 1157 V = 14.5+/-0.5 SEYFERT, NUCLEUS DEC=19D 51' 53.71" +/- 0.5", PLATE-ID=026A Comments: Nuclear magnitude measured from a WFPC1/PC F547M exposure. Nuclear source is nearly pointlike and may be variable. 3 NGC3245 GALAXY, LENTICULAR, RA=10H 27M 18.406S +/- 1", J2000 V = 1358 SURF(V) = 14.5+/-0.2 LINER, NUCLEUS DEC=28D 30' 25.98" +/- 1", PLATE -ID=01AK Comments: Target position and flux measured from a WFPC2/PC F547M image. Surface brightness is the mean value over an 0.2"x0.2" region centered on the nucleus. 4 NGC4036 GALAXY, LENTICULAR, RA=12H 1M 26.89S +/- 0.5", J2000 V = 1397 SURF(V) = 15.0+/-0.3 LINER, NUCLEUS DEC=61D 53' 44.4" +/- 0.5", PLATE-ID=01QZ Comments: Surface brightness is measured from a WFPC2/PC F547M image, and is the average over a 0.2"x0.2" region centered on the nucleus. 5 NGC4278 GALAXY, ELLIPTICAL, RA=12H 20M 6.78S +/- 0.5", J2000 V = 649 SURF(V) = 15.1+/-0.3 LINER, NUCLEUS DEC=29D 16' 50.6" +/- 0.5", PLATE-ID=00DJ Comments: Surface brightness measured from a WFPC2/PC F555W image, and is the average over a region of 0.2"x0.2" centered on the nucleus. 6 NGC4579 GALAXY, SPIRAL, LINER, RA=12H 37M 43.53S +/- 1", J2000 V = 1519 SURF(V) = 15.1+/-0.4 NUCLEUS DEC=11D 49' 5.6" +/- 1", PLATE- ID=00IY Comments: Central surface brightness measured from a ground- based image. 7403( 9) - 08/24/99 09:52 - [ 5] Visit: 01 Visit Priority: 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 NGC3227 WFPC2 IMAGE PC1 F547M 1 10 S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3227 WFPC2 IMAGE PC1 F547M CR-SPLIT=0.5 1 320 S ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3227 WFPC2 IMAGE PC1 F658N 1 30 S ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3227 WFPC2 IMAGE PC1 F658N 1 1600 S ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 6] Visit: 02 Visit Priority: 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 NGC3245 WFPC2 IMAGE PC1 F702W 1 140 S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3245 WFPC2 IMAGE PC1 F658N 1 2200 S ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 7] Visit: 03 Visit Priority: 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 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 5 S ONBOARD ACQ FOR 2, 3, 4 CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=5 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1052 STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO 1 60 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1052 STIS/C ACQ/PEA 52X0.2 MIRROR 1 15 S ONBOARD ACQ FOR 4 CD K ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC1052 STIS/C ACCUM 52X0.2 G750M 6581 PATTERN=PERP-TO-SLIT,NUM-POS=7, 1 2000 S POS TARG -0.75, 0.0 CD STEP-SIZE=0.25, EXPAND PATTERN-DIRECTION=PLUS,CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 8] Visit: 04 Visit Priority: 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 NGC3227 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 1 S ONBOARD ACQ FOR 3, 4 CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=3 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3227 STIS/C ACQ/PEA 52X0.2 MIRROR 1 1 S ONBOARD ACQ FOR 4 CD K ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3227 STIS/C ACCUM 52X0.2 G750M 6581 PATTERN=PERP-TO-SLIT,NUM-POS=7, 1 1600 S POS TARG -0.75, 0.0 CD STEP-SIZE=0.25, EXPAND PATTERN-DIRECTION=PLUS,CR-SPLIT=2 ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 9] Visit: 05 Visit Priority: 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 NGC3245 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 5 S ONBOARD ACQ FOR 3, 4 CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=5 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3245 STIS/C ACQ/PEA 52X0.2 MIRROR 1 15 S ONBOARD ACQ FOR 4 CD K ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3245 STIS/C ACCUM 52X0.2 G750M 6581 PATTERN=PERP-TO-SLIT,NUM-POS=5, 1 2900 S POS TARG -0.5, 0.0 EXPAND CD STEP-SIZE=0.25, PATTERN-DIRECTION=PLUS,CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 10] Visit: 06 Visit Priority: 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 NGC4036 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 5 S ONBOARD ACQ FOR 3, 4 CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=5 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4036 STIS/C ACQ/PEA 52X0.2 MIRROR 1 15 S ONBOARD ACQ FOR 4 CD K ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4036 STIS/C ACCUM 52X0.2 G750M 6581 PATTERN=PERP-TO-SLIT,NUM-POS=5, 1 3100 S POS TARG -0.5, 0.0 EXPAND CD STEP-SIZE=0.25, PATTERN-DIRECTION=PLUS,CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 11] Visit: 07 Visit Priority: 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 NGC4278 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 5 S GS ACQ SCENARIO SINGLE CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=5 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4278 STIS/C ACQ/PEA 52X0.2 MIRROR 1 15 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4278 STIS/C ACCUM 52X0.2 G750M 6581 PATTERN=PERP-TO-SLIT,NUM-POS=2, 1 2900 S POS TARG -0.5, 0.0 EXPAND CD STEP-SIZE=0.25, PATTERN-DIRECTION=PLUS,CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC4278 STIS/C ACQ/PEA 52X0.2 MIRROR 1 15 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC4278 STIS/C ACCUM 52X0.2 G750M 6581 PATTERN=PERP-TO-SLIT,NUM-POS=3, 1 2900 S EXPAND CD STEP-SIZE=0.25, PATTERN-DIRECTION=PLUS,CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 12] Visit: 08 Visit Priority: 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 NGC4579 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 5 S ONBOARD ACQ FOR 2, 3, 4 CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=5 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4579 STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO 1 60 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4579 STIS/C ACQ/PEA 52X0.2 MIRROR 1 15 S ONBOARD ACQ FOR 4 CD K ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4579 STIS/C ACCUM 52X0.2 G750M 6581 PATTERN=PERP-TO-SLIT,NUM-POS=5, 1 2700 S POS TARG -0.5, 0.0 EXPAND CD STEP-SIZE=0.25, PATTERN-DIRECTION=PLUS,CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ 7403( 9) - 08/24/99 09:52 - [ 13] Summary Form for Proposal 7403 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 F28X50LP 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ ACCUM ACQ/PEAK ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 CHECKBOX=5 CR-SPLIT=NO CR-SPLIT=3 CHECKBOX=3 CR-SPLIT=2 DIFFUSE-CENTER=FLUX-CENTROID PATTERN-DIRECTION=PLUS ACQTYPE=DIFFUSE STEP-SIZE=0.25 NUM-POS=2 NUM-POS=3 NUM-POS=5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2, 3, 4 ONBOARD ACQ FOR 4 POS TARG -0.75, 0.0 EXPAND ONBOARD ACQ FOR 3, 4 POS TARG -0.5, 0.0 EXPAND GS ACQ SCENARIO SINGLE EXPAND ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F547M F658N F702W MIRROR G750M ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3227 NGC3245 NGC1052 NGC4036 NGC4278 NGC4579 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 6581 ------------------------------------------------------------------------------------------------------------------------------------