8589( 5) - 02/08/01 17:33 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8589 Version: 5 Check-in Date: 08-Feb-2001 17:32:30 1.Proposal Title: Orbital Structure and Black Hole in NGC 3379 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Karl Gebhardt University of Texas at Austin CoI: Prof. Thomas Statler Ohio University N ------------------------------------------------------------------------------------ 5. Abstract The stellar orbital structure and the mass of the central black hole in dynamically hot galaxies are direct insights into their formation and evolution---both of the black hole and galaxy. We propose to use gas kinematics to determine the central black hole (BH) mass in NGC 3379 to high accuracy. Detailed modeling including this BH mass and previous HST and extensive ground-based data will measure the stellar orbital distribution throughout the galaxy. Recent work suggests that elliptical galaxies tend to have tangentially biased orbits near their centers, consistent with results from BH binary simulations in galaxies. However, knowledge of the central BH mass is one of the limiting factors for providing accurate measurements of the orbital structure. In addition, this data will allow us to compare the mass measured from gas to that measured from stellar kinematics using our previous analysis. An urgent need in BH physics is cross checks between gas and stellar BH masses, particularly in systems where the gas mass promises to be accurate. NGC 3379 is a rare example of a system that lends itself to this comparison. Finally, accurate BH masses are necessary ingredients to characterize the relation, if one exists, between their masses and those of the host galaxy. ------------------------------------------------------------------------------------ 8589( 5) - 02/08/01 17:33 - [ 2] Observations Description ------------------------ In order to understand the morphology of the gas we must obtain both multiple kinematic pointings and a narrow-band image. Using our ground-based and HST/FOS observations, we can conservatively calculate the exposure times for both imaging and spectroscopy. For the imaging, our first goal is to determine the gas configuration, which is not guaranteed to match that of the dust disk in Fig. 1. Second, to measure a central mass to 10% we require a similar accuracy for the logarithmic slope of the gas profile. The first concern is easier and the S/N estimate is driven by the gas profile determination. Based on simulated images, a S/N per 0.2arcsec^2 of 15 will provide an uncertainty less than 10% for the gas profile slope. We determine the exposure time using our FOS spectrum. Figure 3 presents the FOS spectrum around the [NII] 6583AA line. The equivalent width measured from this spectrum is 1.8AA. Given the 28.5AA bandpass of the F658N filter and accurately knowing the stellar contribution from our previous F555W image, we can achieve a S/N per 0.2arcsec^2 of 15 in a one hour exposure. This estimate is based on the assumption that the gas is distributed spherically, and a disk configuration increases our S/N. We have confirmed this number with both the WFPC exposure time calculator and previous observations. For the kinematics, we have two considerations: 1) measure gas kinematics in the dust ring to ensure a robust estimate of the enclosed mass, and 2) determine the state of the gas inside the central 0.5arcsec---i.e., whether it is in a disk and whether random motions need to be included for a proper dynamical analysis. Our ground-based spectra provide the equivalent width of [NII] at the edges of the dust disk, and the HST/FOS spectrum provide it in the inner regions; Fig.1 shows that the FOS spectrum did not include the dust disk gas since it was centered inside the disk, so we have good estimates of the gas in both the central and disk components. We will obtain a two- dimensional velocity map of the dust/gas disk to confirm the kinematic configuration of the gas. The width of the inclined disk is 0.6arcsec. Thus, to provide full coverage, we will orient the slit parallel to the disk major axis and step multiple exposures in the perpendicular direction. We use our current estimate for mass enclosed in the dust ring and the equivalent width of [NII] to estimate exposure times. The enclosed mass in 1arcsec is roughly 5times10^8Msun, with slightly more mass in stars than in a BH. Thus, at 1arcsec ---the radius of the dust disk---the projected gas velocities are around 190\kms, depending on the actual inclination. Obtaining a black hole mass with 10% accuracy requires knowledge of the velocity centroids to around 20%, assuming that we will obtain about 20 spatially independent estimates along the gas disk (0.2arcsec binning), corresponding to 40kms. The equivalent width from our ground-based [NII] spectrum in the dust disk is 0.8AA, with sigma=3.5AA. From Monte-Carlo simulations, an uncertainty of 40kms with 0.8AA equivalent width requires S/N=75. The HST V-band surface brightness profile provides the continuum level, and, binning to 0.2arcsec, we require 3.5 hours per slit position using the G750M grating with the 0.2arcsec slit. We assume the emission is similar around the disk and use the same exposure time for each position. Three adjacent positions with the 0.2arcsec slit will cover the 0.6arcsec disk width. Real Time Justification ----------------------- none Calibration Justification ------------------------- none Additional Comments ------------------- The TAC asked that we observe the narrow-band image first and then re-adjust the STIS observations accordingly, if necessary. ------------------------------------------------------------------------------------ 8589( 5) - 02/08/01 17:33 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3379 GALAXY; ELLIPTICAL RA=10H 47M 49.54S +/- 0.05S, J2000.0 V=940 SURF(V) = 14.6 DEC=+12D 34' 53.8" +/- 0.5", B-V = 1.0 PLATE-ID=0258 Coordinate Source: HST_IMAGE 8589( 5) - 02/08/01 17:33 - [ 4] Visit: 01 Visit Priority: Visit Requirements: PCS MODE F; BEFORE 01-JAN-2001 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 NGC3379 WFPC2 IMAGE PC1-FIX F658N CR-SPLIT=0.5,CR-TOLERANCE=0.2, 1 2500 S ATD-GAIN=7 Comments: This is the narrow-band image that must come first. ------------------------------------------------------------------------------------------------------------------------------------ 8589( 5) - 02/08/01 17:33 - [ 5] Visit: 02 Visit Priority: Visit Requirements: PCS MODE F; ORIENT 130D TO 175D; ORIENT 300D TO 359D; AFTER 1 BY 60D 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 NGC3379 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 30 S CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=9 Comments: Acquire the target. ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3379 STIS/C ACCUM 52X0.2 MIRROR CR-SPLIT=NO 1 4 S CD Comments: Obtain a confirmation image of the final pointing. ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2100 S EXPAND; END ORBIT CD ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG 0, 1.039; CD EXPAND; END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG 0, -1.052; CD EXPAND; END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG 0, 0.52; EXPAND; CD END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG 0, -0.507; CD EXPAND; END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 8589( 5) - 02/08/01 17:33 - [ 6] Visit: 03 Visit Priority: Visit Requirements: PCS MODE F; SAME ORIENT AS 2; AFTER 1 BY 60D 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 NGC3379 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 30 S CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=9 Comments: Acquire the target. ------------------------------------------------------------------------------------------------------------------------------------ 13 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2100 S POS TARG 0.25, 0; EXPAND; CD END ORBIT Comments: Offset position is 0.25" from center ------------------------------------------------------------------------------------------------------------------------------------ 15 NGC3379 STIS/C ACCUM 52X0.2 MIRROR CR-SPLIT=NO 1 4 S CD Comments: Obtain a confirmation image of the final pointing and offset. ------------------------------------------------------------------------------------------------------------------------------------ 16 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2400 S POS TARG 0.25, -1.052; CD EXPAND; END ORBIT Comments: Offset position is 0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 18 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG 0.25, 1.039; CD EXPAND; END ORBIT Comments: Offset position is 0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG 0.25, -0.507; CD EXPAND; END ORBIT Comments: Offset position is 0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 22 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG 0.25, 0.52; CD EXPAND; END ORBIT Comments: Offset position is 0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 8589( 5) - 02/08/01 17:33 - [ 7] Visit: 04 Visit Priority: Visit Requirements: PCS MODE F; SAME ORIENT AS 2; AFTER 1 BY 60D 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 NGC3379 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 30 S CD P DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=9 Comments: Acquire the target. ------------------------------------------------------------------------------------------------------------------------------------ 24 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2100 S POS TARG -0.25, 0; CD EXPAND; END ORBIT Comments: Offset position is -0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 25 NGC3379 STIS/C ACCUM 52X0.2 MIRROR CR-SPLIT=NO 1 4 S CD Comments: Obtain a confirmation image of the final pointing and offset. ------------------------------------------------------------------------------------------------------------------------------------ 26 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2400 S POS TARG -0.25, -1.052; CD EXPAND; END ORBIT Comments: Offset position is -0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 28 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG -0.25, 1.039; CD EXPAND; END ORBIT Comments: Offset position is -0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC3379 STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2 1 2840 S POS TARG -0.25, -0.507; CD EXPAND; END ORBIT Comments: Offset position is -0.25" from center. ------------------------------------------------------------------------------------------------------------------------------------ 8589( 5) - 02/08/01 17:33 - [ 8] Summary Form for Proposal 8589 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX F28X50LP 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 CR-TOLERANCE=0.2 ATD-GAIN=7 CHECKBOX=9 CR-SPLIT=NO CR-SPLIT=2 DIFFUSE-CENTER=FLUX-CENTROID ACQTYPE=DIFFUSE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE F; BEFORE 01-JAN-2001 PCS MODE F; ORIENT 130D TO 175D; ORIENT 300D TO 359D; AFTER 1 BY 60D EXPAND; END ORBIT POS TARG 0, 1.039; EXPAND; END ORBIT POS TARG 0, -1.052; EXPAND; END ORBIT POS TARG 0, 0.52; EXPAND; END ORBIT POS TARG 0, -0.507; EXPAND; END ORBIT PCS MODE F; SAME ORIENT AS 2; AFTER 1 BY 60D POS TARG 0.25, 0; EXPAND; END ORBIT POS TARG 0.25, -1.052; EXPAND; END ORBIT POS TARG 0.25, 1.039; EXPAND; END ORBIT POS TARG 0.25, -0.507; EXPAND; END ORBIT POS TARG 0.25, 0.52; EXPAND; END ORBIT POS TARG -0.25, 0; EXPAND; END ORBIT POS TARG -0.25, -1.052; EXPAND; END ORBIT POS TARG -0.25, 1.039; EXPAND; END ORBIT POS TARG -0.25, -0.507; EXPAND; END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F658N MIRROR G750M ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3379 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 6581 ------------------------------------------------------------------------------------------------------------------------------------