5942( 10) - 01/25/96 07:55 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5942 Version: 10 Check-in Date: 25-Jan-1996 07:50:29 1.Proposal Title: THE NATURE OF THE STAR FORMATION TRIGGER IN NGC 1068 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Frederick Bruhweiler The Catholic University of America CoI: Andrew M. Smith NASA/Goddard Space Flight Center N CoI: Wayne Landsman STX Corporation N CoI: Eliot Malumuth Computer Sciences Corporation N CoI: Allen Home Catholic University of America N CoI: Dennis Ebbets Ball Areospace Group N ------------------------------------------------------------------------------------ 6. Abstract We propose to use the GHRS/G140L and the PC of the WFPC2 to observe four very bright and luminous starburst knots and the nebular emission within the inner 3 Kpc region of NGC 1068. The resulting spectra of the knots will be modeled with our population synthesis code, which incorporates a new library of high dispersion IUE stellar spectra. The use of this powerful new tool will place strong constraints on the stellar ages and the star formation history in these knots. These data in combination with the PC imagery will be compared with the the expectations for the possible triggering mechanisms that might be responsible for the luminous knot in the inner 3 Kpc. Specifically, we will explore if our inferred ages for the knots and the high angular resolution emission line morphology are consistent with the star formation being initiated by the strong radiation field from the central AGN, stochastic processes, or passage of spiral density waves through the inner CO Ring of the galaxy. ------------------------------------------------------------------------------------ 5942( 10) - 01/25/96 07:55 - [ 2] Observations Description ------------------------ Spectra will be acquired of four individual starburst knots within the central 3 kpc region of NGC 1068. The knots to be observed are knots 1, 3, 4, and 8a (see Fig. 1 & Bruhweiler, Truong, and Altner 1991). Knots 1 & 4 lie inside the beam of photoionizing radiation from the nucleus, while the other two knots lie outside. These observations will be made using the GHRS with the G140L configuration through the 1.74"x1.74" Large Science Aperture. The GHRS/G140L combination is about a factor of 2 more sensitive and yields almost a factor of two better resolution than the FOS high resolution gratings. Knots 1, 3, and 4 are estimated to be less than 1.75'' in diameter, as determined from a previous WFPC imagery in the U -band. The effective spectral resolution will be ~ 5 times better than our IUE data with a much better S/N ratio as well. (All the data will be at least the quality of knot No.2 shown in Fig.2) Exposure Time Estimates & Orbit Calculation: We estimated flux levels for the knots based upon IUE data in Bruhweiler, Truong, & Altner (1991), and on our previous U- band WFPC imagery for the knots obtained in program 3852. We used the flux above for 1350Angstrom\\\\ and multiplied by the sensitivity for the G140L (166x10^11) given in Table 8-2 in the GHRS handbook. For comb=4, these count rates are divided by 4 to give the counts/datapoint. for the G140L. For each knot exposures are calculated to maximize the use of the orbits. For knot 1, we get a count rate/diode=0.41cts/s, or or count rate/datapoint=0.1cts/s. There are 52 available minutes per orbit. Subtracting(11+12) minutes for acquisition and 8 min for peak-up, leaves 21 minutes for exposures. Allowing 4 minutes per exposure before reading out (1 minute), to avoid smearing due the the Earth's magnet field, gives 4-4min exposure segments for the first orbit. This is shy of the S/N=10. The second orbit, counting again the 1 minute readout for each 4 min exposure segment, gives another 40 min available for actual exposures. For a total of 52 minutes exposure for the 2 orbits, we get a total of 290 counts/datapoint or S/N=17. In the table below, we give the estimated exposure information for each of the knots to be observed. The instrument to be used, grating settings, wavelength coverage, observed fluxes estimated from our previous IUE and GHRS work, requested exposure time, and S/N are given in the table. noindent Instrument Grating Wavelength Flux Exp.(min.) (S/N), KNOT \\\\#1:, GHRS G140L 1170-1450 2.5E-14 52 17, KNOT \\\\#3:, GHRS G140L 1170-1450 1.2E- 14 52 12, KNOT \\\\#4:, GHRS G140L 1170-1450 9.0E-15 96 14, KNOT \\\\#8A:, GHRS G140L 1170-1450 7.5E-15 96 12, --------------------------------- -------- -----------------------------, The spectra can all be obtained in ten (10) orbits. IMAGERY During episode 4, Holland Ford (program 5124) is obtaining Planetary Camera imagery with a large filter sample to explore the nebular emission associated with the AGN of NGC 1068. This imagery, if obtained, would be ideal for our purposes. We propose to use these data when they become available and to acquire additional exposures in other bandbasses necessary for proper interpretation of nebular emission associated with the UV knots. We request 3 additional PC images to complement those to be acquired during Cycle 4. We will acquire PC imagery using the following filters and exposures, F160BW (2x1200sec), F487N (2x400 sec), and F814W (2x400sec). These will be combined with existing or soon to be acquired imagery to obtain absolute fluxes for H Alpha and to gain complete UV photometry for the UV-knots (F160BW), and to correct for stellar continuum in H Alpha\\\\ imagery and to serve as a check on the redleak for the F336W filter. Real Time Justification ----------------------- Not Applicable. Not Applicable Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5942( 10) - 01/25/96 07:55 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5942( 10) - 01/25/96 07:55 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1068-NUC GALAXY, NUCLEUS RA=02H 42M 40.6S +/- 0.04",DEC=- J2000.0 V=1136 SURF(V) = 14 00D 00' 48" +/- 0.04" E(B-V) = 0.0 Comments: Galactic Extinction ( B Mag)=0.05 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0 2 NGC1068-POS1 GALAXY,STAR FORMING RA=02H 42M 40.30S +/- 0.04",DEC= J2000.0 V=1136 SURF(V) = 14 REGION -00D 00' 37.58" +/- 0.04", PLATE E(B-V) = 0.0 -ID=0085 Comments: Estimated Flux(1170-1450 A)=2.5E-14 erg cm-2s-1A-1 Galactic Extinction (B Mag) = 0.05 3 NGC1068-POS3 GALAXY, STAR FORMING RA=02H 42M 39.92S +/- 0.04",DEC= J2000.0 V=1136 SURF(V) = 14 REGION -00D 00' 44.68" +/- 0.04", PLATE E(B-V) = 0.0 -ID=0085 Comments: Estimated Flux(1170-1450 A)=1.2E-14 erg cm-2s-1A-1 Galactic Extinction (B Mag) = 0.05 4 NGC1068-POS4 GALAXY, STAR FORMING RA=02H 42M 41.45S +/- 0.04",DEC= J2000.0 V=1136 SURF(V) = 14 REGION -00D 00' 37.18" +/- 0.04", PLATE E(B-V) = 0.0 -ID=0085 Comments: Estimated Flux(1170-1450 A)=9.0E-14 erg cm-2s-1A-1 Galactic Extinction (B Mag) = 0.05 5 NGC1068- GALAXY, STAR FORMING RA=02H 42M 39.87S +/- 0.04",DEC= J2000.0 V=1136 SURF(V) = 14 POS8A REGION -00D 00' 58.18" +/- 0.04", PLATE E(B-V) = 0.0 -ID=0085 Comments: Estimated Flux(1170-1450 A)=7.5E-14 erg cm-2s-1A-1 Galactic Extinction (B Mag) = 0.05 6 NGC1068-NUC- GALAXY, NUCLEUS RA=02H 42M 40.64S +/- 0.04",DEC= J2000.0 V=1136 SURF(V) = 14 ACQ -00D 00' 47.58" +/- 0.04", PLATE E(B-V) = 0.0 -ID=0085 Comments: Galactic Extinction ( B Mag)=0.05. New target created after early acquisition data from visit 01. 5942( 10) - 01/25/96 07:55 - [ 5] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Purpose is to obtain PC imagery Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1068-NUC WFPC2 IMAGE PC1 F160BW 1523 CR-SPLIT=DEF 1 2400S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1068-NUC WFPC2 IMAGE PC1 F487N 4866 CR-SPLIT=DEF 1 3400S ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC1068-NUC WFPC2 IMAGE PC1 F673N 6732 CR-SPLIT=DEF 1 1800S ------------------------------------------------------------------------------------------------------------------------------------ 5942( 10) - 01/25/96 07:55 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Visit has now been taken off hold Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC1068-NUC HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,S 1 50S ONBOARD ACQ FOR 20-40; -ACQ EARCH-SIZE=5 Comments: Acquisition for offset slew to NGC1068-knot1; STEP-TIME=2.0S ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC1068- HRS ACCUM 2.0 G140L 1313 FP-SPLIT=STD 7 435.2S POS4 Comments: SPECTRUM OF KNOT#4 1170-1456 ANG ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC1068- HRS ACCUM 2.0 G140L 1313 FP-SPLIT=STD 7 435.2S POS4 Comments: SPECTRUM OF KNOT#4 1170-1456 ANG ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC1068- HRS ACQ 2.0 MIRROR-N1 1 18S ONBOARD ACQ FOR 50-80; POS1 Comments: ACQ ON KNOT #1. STEP-TIME=2.0S ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC1068- HRS ACCUM 2.0 G140L 1313 FP-SPLIT=STD 7 435.2S POS1 Comments: Spectrum of Knot#1 1170-1456 Ang ------------------------------------------------------------------------------------------------------------------------------------ 60 NGC1068- HRS ACCUM 2.0 G140L 1313 FP-SPLIT=STD 7 435.2S POS3 Comments: SPECTRUM OF KNOT#3 1170-1456 ANG ------------------------------------------------------------------------------------------------------------------------------------ 70 NGC1068- HRS ACCUM 2.0 G140L 1313 FP-SPLIT=STD 6 435.2S POS8A Comments: SPECTRUM OF KNOT#8A 1170-1456 ANG ------------------------------------------------------------------------------------------------------------------------------------ 80 NGC1068- HRS ACCUM 2.0 G140L 1313 FP-SPLIT=STD 6 435.2S POS8A Comments: SPECTRUM OF KNOT#8A 1170-1456 ANG ------------------------------------------------------------------------------------------------------------------------------------ 5942( 10) - 01/25/96 07:55 - [ 7] Summary Form for Proposal 5942 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=DEF SEARCH-SIZE=5 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 20-40; ONBOARD ACQ FOR 50-80; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160BW F487N F673N MIRROR-N1 G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1068-NUC NGC1068-NUC-ACQ NGC1068-POS4 NGC1068-POS1 NGC1068-POS3 NGC1068-POS8A ------------------------------------------------------------------------------------------------------------------------------------