6826( 3) - 02/19/96 14:52 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6826 Version: 3 Check-in Date: 19-Feb-1996 10:59:59 1.Proposal Title: The Galactic Wind in M82: Structure and Excitation of the Optical Filaments ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle GALAXIES & CLUSTERS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Patrick Shopbell California Institute of Technology CoI: Jonathan Bland-Hawthorn Anglo Australian Observatory N CoI: Reginald Dufour Rice University N CoI: Judith Cohen California Institute of Technology N ------------------------------------------------------------------------------------ 6. Abstract We propose to use the WFPC2 camera to obtain narrow-band images of the optical filaments associated with the galactic wind in NGC 3034 (M82). We will image the filaments in the emission lines of H-Alpha, [NII] 6583, [OI] 6300, and [OIII] 5007. The H-Alpha imagery will provide a map of the optical emission associated with both lobes of the outflow, at much higher resolution than ever before studied. From recent ground-based imagery and Fabry-Perot observations with 1"-2"\ resolution, we expect the increased resolution of HST to reveal immense detail in the filament system and allow for accurate isolation of the filamentary structure from the background. The [NII], [OI], and [OIII] imagery will provide high-resolution maps of the filament excitation, leading to improved models of the outflow emission mechanisms and energetics. ------------------------------------------------------------------------------------ 6826( 3) - 02/19/96 14:52 - [ 2] Observations Description ------------------------ Observations in the emission line of H-Alpha (filter F656N) have been chosen to provide a high resolution map of the galactic wind in NGC 3034. For this purpose, flux measurements from ground-based narrow-band imaging and Fabry- Perot observations were used to estimate the exposure times. Using the procedure described in Section 6.5 of the Wide Field and Planetary Camera 2 Instrument Handbook and assuming a desired S/N of 3, the estimated H-Alpha flux per pixel at the most distant galactic radius in the field requires an exposure of approximately 1000 seconds. The on-line WFPC2 exposure calculator gives a more accurate suggested exposure time of 990 seconds; we will use 1000 seconds. In order to investigate the excitation variations in the wind, observations will also be made in the emission lines of [NII] 6583 (filter F658N), [OI] 6300 (filter F631N), and [OIII] 5007 (filter F502N). Again using ground-based flux measurements, the exposure times for the [NII], [OI], and [OIII] images are calculated as above to be 1200, 1200, and 3500 seconds, respectively, for a desired S/N of 3. The [OIII] exposure time is long due to the faintness of emission in the high-excitation line and the much lower filter throughput. In the interest of conserving spacecraft time, we will image only the southern outflow lobe in [OI] and [OIII]. Because NGC 3034 is inclined by approximately 81 degrees, the northern outflow is obscured slightly by the disk. The southern lobe therefore appears significantly larger and brighter. (Some authors have also argued that the starburst power source lies preferentially toward the southern side of the disk.) We expect the H-Alpha and [NII] observations of the northern lobe to be sufficient to demonstrate that the physics of the two lobes is comparable. Finally, in order to enable continuum subtraction, an off-band (filter F547M) image of the southern lobe will be taken. A comparison of the dimensionless efficiencies of the F656N and F547M filters (Table 68 in the WFPC2 Instrument Handbook) suggests an exposure time of approximately one minute to obtain a comparable continuum to that seen in the H-Alpha image. We will use 100 seconds. Our previous studies have shown that the range of radial velocities in the wind filaments is only +/-175 km/s. Even when superimposed on the systemic velocity of 203 km/s, the narrow-band filter bandpasses given in Section 8.2 of the Wide Field and Planetary Camera 2 Instrument Handbook will be more than sufficient to encompass all of the filament line emission. All three narrow-band filters (F656N, F658N, F502N) extend at least 8 Angstroms beyond the rest wavelength of the emission line. The southern lobe filaments, upon which we are concentrating this study, are particularly well placed in velocity -- the southern outflow is blue-shifted (see Fig. 1) and therefore exhibits a net radial velocity approaching zero. To summarize, we propose two visits: The first visit will image the northern lobe of the NGC 3034 outflow through the F656N and F658N filters, using 1000 and 1200 second exposures, respectively, in one orbit. The second visit will image the southern lobe of the outflow through the F656N, F658N, F502N, F631N, and F547M filters. The exposures through the F656N and F658N filters will use 1000 and 1200 seconds, respectively, and complete a second orbit. The third orbit will consist of a 2300 second exposure of the southern lobe through the F502N filter, followed by a 100 second continuum exposure through the F547M filter. The fourth and final orbit will consist of a 1200 second exposure through the F502N filter, completing the [OIII] observation, and a 1200 second exposure through the F631N filter. These two visits will image almost the entire spatial extent of the optical filaments associated with the outflow in NGC 3034, with emphasis on the closer and more extended southern lobe. All exposures will use the CR-SPLIT option. It should be noted that NGC 3034 lies in the wings of the CVZ, with a single 29-hour opportunity, although we are not submitting this proposal specifically for CVZ scheduling. Real Time Justification ----------------------- A roll angle which places the PC1 and WF3 chips along the axis of the outflow approximately 146 degrees East of North), with PC1 closest to the galaxy center, is desirable, but not required. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6826( 3) - 02/19/96 14:52 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6826( 3) - 02/19/96 14:52 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3034- GALAXY,WIND,STARBURST,F RA=09H 55M 51.23S +/- J2000 V = 203 SURF-LINE(6563)=1.4+/-0.5e-15 OUTFLOW ILAMENT,ULTRALUMINOUS 0.08S,DEC=69D 40' 42.93" +/- SURF-LINE(6583)=1.1+/-0.5e-15 IR GAL,EXT- 1.25" SURF-LINE(5007)=1.1+/-0.5e-15 MEDIUM,BIPOLAR Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 6826( 3) - 02/19/96 14:52 - [ 5] Visit: 01 Visit Requirements: ORIENT 140D TO 170D On Hold Comments: Additional Comments: We would like the U3 axis placed along the northern minor axis of the galaxy, 155D, to within +/-15D, with the PC centered on the nucleus. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3034- WFPC2 IMAGE PC1-FIX F656N CR-SPLIT=0.5 1 1000S NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3034- WFPC2 IMAGE PC1-FIX F658N CR-SPLIT=0.5 1 1300S NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 6826( 3) - 02/19/96 14:52 - [ 6] Visit: 02 Visit Requirements: ORIENT 320D TO 350D On Hold Comments: Additional Comments: We would like the U3 axis placed along the southern minor axis of the galaxy, 335D, to within +/-15D, with the PC centered on the nucleus. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3034- WFPC2 IMAGE PC1-FIX F656N CR-SPLIT=0.5 1 1000S NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3034- WFPC2 IMAGE PC1-FIX F658N CR-SPLIT=0.5 1 1300S NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3034- WFPC2 IMAGE PC1-FIX F502N CR-SPLIT=0.5 1 2300S EXPAND NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3034- WFPC2 IMAGE PC1-FIX F547M CR-SPLIT=0.5 1 100S NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3034- WFPC2 IMAGE PC1-FIX F502N CR-SPLIT=0.5 1 1200S NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC3034- WFPC2 IMAGE PC1-FIX F631N CR-SPLIT=0.5 1 1200S NO SPLIT OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------ 6826( 3) - 02/19/96 14:52 - [ 7] Summary Form for Proposal 6826 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 140D TO 170D NO SPLIT ORIENT 320D TO 350D EXPAND NO SPLIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F656N F658N F502N F547M F631N ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3034-OUTFLOW ------------------------------------------------------------------------------------------------------------------------------------