9104( 3) - 02/06/02 09:08 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9104 Version: 3 Check-in Date: 27-Feb-2001 10:26:34 1.Proposal Title: A WFPC2 Study of Proplyds and a Protostellar Condensation at the Center of M20 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Farhad Yusef-Zadeh Northwestern University CoI: Dr. John Biretta Space Telescope Science Institute N CoI: Prof. Robert O'Dell Vanderbilt University N CoI: Dr. Mark Wardle University of Sydney N ------------------------------------------------------------------------------------ 5. Abstract The Trifid nebula (M20) is a well-known prominent optical HII region trisected by bands of obscuring dust lanes and excited by an O7.5 star HD 164492A. Our recent study of near-IR ground-based observations of this region at J, H, K and L show all seven components of HD 164492 (A to G) identified optically. Our sub-arcsecond radio continuum VLA and ground- based observations of M20 also show free-free emission from three stellar sources (B, C and D) and a bright rim outlining a protostellar condensation (TC1) lying close to the O7V star (HD 164492A) at the center of the nebula. Based on a number of strong arguments, these stars have disks associated with them and their envelopes are photoionized externally by the UV radiation from the hot central star, HD 164492A. The proposed WFPC2 observations are intended to search for neutral protoplanetary disks ``proplyds'', to study the optically bright rim of ionized gas associated with TC1 for signs of star formation, and to make a detailed subarcsecond determination of extinction toward the dust lanes of M20 using HAlpha and 6cm data. ------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 2] Observations Description ------------------------ We will image the central region of the nebula which contains the cluster of stars and the brightest ionized rims (TC1). Searching for proplyds around the bright stars will require a sequence of short exposures on PC1 to avoid saturation. Proplyds similar to those in Orion would be easily detected around many faint stars like E, F, and G (V ~ 12). The median H-alpha surface brightness for the proplyds in Orion is about 200 e-16 erg/cm2/s. In a 60s exposure in F656N this gives about 2000 electrons, or SNR=44, per PC pixel. In the same exposure the V=12 stars will have 16000 electrons/pixel at the peak of each PSF (56\ saturation), and about 2000 electrons/pixel at a radius of 2 pixels (0.1") from the PSF center. Hence proplyds 0.1" in radius (scaling from Orion) would be easily detected as factor ~ 2 excess counts in the PSF wings (~ 40Sigma detection per pixel). Proplyds around brighter stars C and D (V=8.6) would also be easily detected if they were somewhat larger (radius 0.15" - 0.2"; ~ 10Sigma per pixel). We would use a range of exposure times to insure non-saturated images for the brighter stars, and use dithering and two HST roll -angles to improve PSF sampling and subtractions. One orbit each is needed at each roll angle. Study of TC1 will use longer exposures in four WFPC2 filters: HAlpha (F656N), SII (F673N), OIII (F502N), and F547M, which will provide a continuum image. TC1 has been studied in detail by the 92cm telescope at Kitt Peak by Lynds and O'Neil (1985). They give an HAlpha intensity associated with the rim of 1.5 * 10^-3 ergs cm^-2 s^-1 sr^-1 which is superposed on background of about 3 * 10^-3 ergs cm^-2 s^-1 sr^-1. Our planned 2000s F656N exposure hence gives SNR~ 20 per WF pixel on the rim; similar SNR will be obtained in the other filters. This requires a total of four orbits. We added filter F631N after realizing that one of the best signatures of protoplanetary disk is the detection of OI emission from the disk. Also F658N was added to calibrate out NII contaminated Halpha filters. The goal of our science is not changed by using these new filters. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD164492A ISM, HII Region RA=18H 02M 23.40S +/- 0.010S, J2000 V = 70.6 DEC=-23D 01' 53.7" +/- 0.10", B-V = -0.30 PLATE-ID=067R Coordinate Source: GUIDE_STAR_CATALOG Comments: brightest star at nebula center, type OV0.5; GSC says mag 6.66 11 M20-TC2- ISM, HII Region RA = 18H02M23.53S +/- 1.0", DEC J2000 V = 20.0 BRIDGE = -23D03'40.13" +/- 1.0", PLATE- ID = 067R Coordinate Source: GSC_SURVEY_PLATE 12 M20-TC1 ISM, HII Region RA = 18H02M27.17S +/- 1.0", DEC J2000 V = 20.0 = -23D01'22.17" +/- 1.0", PLATE- ID = 067R Coordinate Source: GSC_SURVEY_PLATE 13 M20-SW ISM, HII Region RA = 18H02M13.54S +/- 1.0", DEC J2000 V = 20.0 = -23D02'12.52" +/- 1.0", PLATE- ID = 067R Coordinate Source: GSC_SURVEY_PLATE 9104( 3) - 02/06/02 09:08 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 81D TO 85D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD164492A WFPC2 IMAGE PC1 F656N 6560 CLOCKS=YES,CR-SPLIT=0.09091, 1 23 S CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 11 HD164492A WFPC2 IMAGE PC1 F656N 6560 CLOCKS=YES,CR-SPLIT=0.09091, 1 23 S POS TARG 0.25, 0.25 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD164492A WFPC2 IMAGE PC1 F658N 6580 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S SAME POS AS 11 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 21 HD164492A WFPC2 IMAGE PC1 F658N 6580 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD164492A WFPC2 IMAGE PC1 F502N 5007 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 31 HD164492A WFPC2 IMAGE PC1 F502N 5007 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S SAME POS AS 11 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD164492A WFPC2 IMAGE PC1 F631N 6310 CLOCKS=YES,CR-SPLIT=0.09091, 1 12 S SAME POS AS 11 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 41 HD164492A WFPC2 IMAGE PC1 F631N 6310 CLOCKS=YES,CR-SPLIT=NO, 1 10 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 5] Visit: 02 Visit Priority: Visit Requirements: ORIENT 150D TO 160D FROM 1 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD164492A WFPC2 IMAGE PC1 F656N 6560 CLOCKS=YES,CR-SPLIT=0.09091, 1 23 S CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 11 HD164492A WFPC2 IMAGE PC1 F656N 6560 CLOCKS=YES,CR-SPLIT=0.09091, 1 23 S POS TARG 0.25, 0.25 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD164492A WFPC2 IMAGE PC1 F658N 6580 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S SAME POS AS 11 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 21 HD164492A WFPC2 IMAGE PC1 F658N 6580 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD164492A WFPC2 IMAGE PC1 F502N 5007 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 31 HD164492A WFPC2 IMAGE PC1 F502N 5007 CLOCKS=YES,CR-SPLIT=0.09091, 1 16 S SAME POS AS 11 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD164492A WFPC2 IMAGE PC1 F631N 6310 CLOCKS=YES,CR-SPLIT=0.09091, 1 12 S SAME POS AS 11 CR-TOLERANCE=0.0,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 41 HD164492A WFPC2 IMAGE PC1 F631N 6310 CLOCKS=YES,CR-SPLIT=NO, 1 10 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 6] Visit: 10 Visit Priority: Visit Requirements: ORIENT 81D TO 85D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD164492A WFPC2 IMAGE PC1 F656N 6560 CLOCKS=YES,CR-SPLIT=0.5, 1 400 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD164492A WFPC2 IMAGE PC1 F502N 5007 CLOCKS=YES,CR-SPLIT=0.5, 1 520 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD164492A WFPC2 IMAGE PC1 F673N 6730 CLOCKS=YES,CR-SPLIT=0.5, 1 600 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD164492A WFPC2 IMAGE PC1 F547M 5470 CLOCKS=YES,CR-SPLIT=0.5, 1 80 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 7] Visit: 11 Visit Priority: Visit Requirements: ORIENT 351D TO 355D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 M20-TC2-BRI WFPC2 IMAGE WFALL-F F656N 6560 CLOCKS=YES,CR-SPLIT=0.5, 1 400 S DGE IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 M20-TC2-BRI WFPC2 IMAGE WFALL-F F502N 5007 CLOCKS=YES,CR-SPLIT=0.5, 1 520 S DGE IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 30 M20-TC2-BRI WFPC2 IMAGE WFALL-F F673N 6730 CLOCKS=YES,CR-SPLIT=0.5, 1 600 S DGE IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 40 M20-TC2-BRI WFPC2 IMAGE WFALL-F F547M 5470 CLOCKS=YES,CR-SPLIT=0.5, 1 80 S DGE IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 8] Visit: 12 Visit Priority: Visit Requirements: ORIENT 261D TO 265D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 M20-TC1 WFPC2 IMAGE WFALL-F F656N 6560 CLOCKS=YES,CR-SPLIT=0.5, 1 400 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 M20-TC1 WFPC2 IMAGE WFALL-F F502N 5007 CLOCKS=YES,CR-SPLIT=0.5, 1 520 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 30 M20-TC1 WFPC2 IMAGE WFALL-F F673N 6730 CLOCKS=YES,CR-SPLIT=0.5, 1 600 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 40 M20-TC1 WFPC2 IMAGE WFALL-F F547M 5470 CLOCKS=YES,CR-SPLIT=0.5, 1 80 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 9] Visit: 13 Visit Priority: Visit Requirements: ORIENT 81D TO 85D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 M20-SW WFPC2 IMAGE WFALL-F F656N 6560 CLOCKS=YES,CR-SPLIT=0.5, 1 400 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 M20-SW WFPC2 IMAGE WFALL-F F502N 5007 CLOCKS=YES,CR-SPLIT=0.5, 1 520 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 30 M20-SW WFPC2 IMAGE WFALL-F F673N 6730 CLOCKS=YES,CR-SPLIT=0.5, 1 600 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 40 M20-SW WFPC2 IMAGE WFALL-F F547M 5470 CLOCKS=YES,CR-SPLIT=0.5, 1 80 S IX ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 9104( 3) - 02/06/02 09:08 - [ 10] Summary Form for Proposal 9104 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 WFALL-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CLOCKS=YES CR-SPLIT=0.09091 CR-TOLERANCE=0.0 ATD-GAIN=15 CR-SPLIT=NO CR-SPLIT=0.5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 81D TO 85D POS TARG 0.25, 0.25 SAME POS AS 11 ORIENT 150D TO 160D FROM 1 ORIENT 351D TO 355D ORIENT 261D TO 265D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F656N F658N F502N F631N F673N F547M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD164492A M20-TC2-BRIDGE M20-TC1 M20-SW ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 6560 6580 5007 6310 6730 5470 ------------------------------------------------------------------------------------------------------------------------------------