8247( 3) - 11/09/99 16:05 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8247 Version: 3 Check-in Date: 17-Feb-1999 11:47:14 1.Proposal Title: Hidden new-born massive stars in compact H II ``blobs'' of the Large Magellanic Cloud ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Mohammad Heydari-Malayeri Observatoire de Paris CoI: Dr. Michael R. Rosa Space Telescope European Coordinating N Facility, European Southern Observatory CoI: Dr. Hans Zinnecker Potsdam Astrophysical Institute N CoI: Dr. Lise Deharveng Observatoire de Marseille N CoI: Dr. Vassilishspace*.1cm Charman Observatoire de Paris N ------------------------------------------------------------------------------------ 5. Abstract High spatial resolution imaging with WFPC2 is necessary to resolve very tight clusters of massive stars at birth in the Large Magellanic Cloud. These are the youngest massive stars accessible to direct observations at ultraviolet and optical wavelengths. Situated in an extremely rare category of H II regions in the Magellanic Clouds (only 5'' to 10'' across and of very high excitation), these stars should rank among the hottest ones in these galaxies. Using medium-band continuum filters, we will place the resolved components on color- magnitude diagrams to identify the exciting and youngest stars for follow up STIS spectroscopy. Imaging in HBeta, [O III] , and HAlpha will allow us to correct for the extinction and for the nebular emission. Following our recent HST result on the SMC ``blobs'' N81 (STScI Press Release 98-25, July 1998) and N88A, we are confident that the planned observations will uncover the stellar contents of the LMC objects N160A1, N83B-1, and N11A. These objects provide exceptional opportunities for studying various key phenomena related to massive star formation, in particular whether these massive stars form in isolation or inside co-spatial tight clusters. The observations will also enable us to study the ``blob'' phenomenon at different evolutionary stages in the chemically distinct evironments of the SMC and the LMC. ------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 2] Observations Description ------------------------ We have three LMC targets to be observed with PC2 through various narrow and medium band filters. We use the same strategy that has proved successful with our project GO 6535. A UBV-like photometry will use medium-band continuum filters U (F410M), B (F467M), and V (F547M) in order to avoid the nebular emission lines. Comparison of the medium-band U with ``Wide U'' (F300W) will allow us to estimate the nebular continuum contribution and provide additional leverage in the T_eff-vs-reddening parameter space. We generally obtain two sets of exposures (each CR split) in each filter, a short one to cover the brighter embedded stars and a longer one to obtain enough S/N on the fainter components. Dithering is used in order to minimize the effects of undersampling and to reduce the effects of hot pixels. Narrow-band filters to be used for obtaining information about several non-stellar aspects of the compact regions are F502N, F487N and F656N. In order to estimate the exposure times we startet from the global nebular magnitudes given in the Observing Summary table. These are certainly upper limits for the embedded stars. We consider two cases, either the target contains 1) two stars, or 2) three stars of identical magnitudes. The typical point source magnitudes for e.g. N160A1 will be 13.25 (if two stars) and 13.69 (if three stars). Then, using the WFPC2 Exposure Time Calculator (PC configuration), we derive the maximum exposure times (allowed quantized values) for each filter keeping the maximum count level per pixel within the saturation level (27000 e^- pix^- 1). We assume an O5 spectrum and use the color excess corresponding to each ``blob''. The gain will be 7 e^-/DN and the star located on the CCD pixel center. Since we aim at the photometry of bright and faint targets, we take two sets of CR-split exposures per filter and target (4 for the stellar filters on N160A). The second (and higher sets) are offset for dithering purposes, either on WF or PC scales. This way we get S/N of 3 for stars ~ 10 mag fainter than the brightest cluster point sources. We have also considered the effects of the nebular continuum and emission lines. As an example, in the case of N160A1 which has a radius of 3", the observed F(HBeta) = 8.13 * 10^-12 erg s^-1 cm^-2 is distributed over 28 arcsec^2. This gives 6.08,* 10^-16 erg s^-1 cm^-2 pix^-1 at the PC2 resolution. From our ground-based spectroscopy we know that the continuum emission at HBeta is sim 0.5 * 10^-3 the HBeta line emission in the 4000 to 6000 A range, corresponding to sim 3 * 10^-19 erg, s^-1 cm^-2 pix^-1. This is equivalent to ~ 25.5 mag pix^ -1 or 23.8 mag per 10 typical pixels for a star. Consequently, we do not need to worry about the nebular continuum. The nebular emission line images HAlpha, HBeta, and O III will be at least 1200 times brighter, and thus will be about as bright as the B8 stars. Real Time Justification ----------------------- None Calibration Justification ------------------------- Additional Comments ------------------- PLEASE NOTE: There is a discrepancy between the ORIENT/ROLL definitions in the PhaseII Cyc8 Handbook (Fig. 7.1) and the WFPC2 Handbook (Fig 1.1). We could not resolve this before submission, and may have to change the visit ORIENT requirements within the next couple of days. ------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 3] Data Distribution Paper Products: YES Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LMC-N160A1- EXT-CLUSTER, OB RA=05H 39M 44.00S +/- .1S, DEC=- J2000 V = 16 PC1 Association 69D 38' 46.00" +/- .2", PLATE- B-V = 0.00 ID=06B0 E(B-V) = 0.1 Comments: FLUX FOR BRIGHTEST STAR EXPECTED IN CLUSTER, NEB FAINTER, PC1 2 LMC-N160A1- EXT-CLUSTER, OB RA=05H 39M 44.00S +/- .1S, DEC=- J2000 V = 16 WF2 Association 69D 38' 41.00" +/- .2", PLATE- B-V = 0.00 ID=06B0 E(B-V) = 0.1 Comments: FLUX FOR BRIGHTEST STAR EXPECTED IN CLUSTER, NEB FAINTER, WF2 3 LMC-N11A-PC1 EXT-CLUSTER, OB RA=04H 57M 16.01S +/- .1S, DEC=- J2000 V = 16 Association 66D 23' 21.00" +/- .2", PLATE- B-V = 0.00 ID=06AF E(B-V) = 0.1 Comments: FLUX FOR BRIGHTEST STAR EXPECTED IN CLUSTER, NEB FAINTER, PC1 4 LMC-N11A-WF2 EXT-CLUSTER, OB RA=04H 57M 16.01S +/- .1S, DEC=- J2000 V = 16 Association 66D 23' 20.60" +/- .2", PLATE- B-V = 0.00 ID=06AF E(B-V) = 0.1 Comments: FLUX FOR BRIGHTEST STAR EXPECTED IN CLUSTER, NEB FAINTER, WF2 5 LMC-N83B1- EXT-CLUSTER, OB RA=04H 54M 25.44S +/- .1S, DEC=- J2000 V = 16 PC1 Association 69D 11' 00.00" +/- .2", PLATE- B-V = 0.00 ID=05ZW E(B-V) = 0.1 Comments: FLUX FOR BRIGHTEST STAR EXPECTED IN CLUSTER, NEB FAINTER, PC1 6 LMC-N83B1- EXT-CLUSTER, OB RA=04H 54M 25.44S +/- .1S, DEC=- J2000 V = 16 WF2 Association 69D 11' 00.86" +/- .2", PLATE- B-V = 0.00 ID=05ZW E(B-V) = 0.1 Comments: FLUX FOR BRIGHTEST STAR EXPECTED IN CLUSTER, NEB FAINTER, WF2 8247( 3) - 11/09/99 16:05 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 335D TO 360D ORIENT 0D TO 145D On Hold Comments: Additional Comments: STELLAR FILTERS, LMC-N160A1 CENTERED IN PC1, BEST ROLL 45D Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 100 LMC-N160A1- WFPC2 IMAGE PC1-FIX F300W 2 14 S PC1 ------------------------------------------------------------------------------------------------------------------------------------ 101 LMC-N160A1- WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 100 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 102 LMC-N160A1- WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 100 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 103 LMC-N160A1- WFPC2 IMAGE PC1-FIX F410M 2 50 S SAME POS AS 100 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 110 LMC-N160A1- WFPC2 IMAGE PC1-FIX F410M 2 50 S POS TARG +0.345,+0.345 PC1 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 111 LMC-N160A1- WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 110 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 112 LMC-N160A1- WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 110 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 113 LMC-N160A1- WFPC2 IMAGE PC1-FIX F300W 2 14 S SAME POS AS 110 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 120 LMC-N160A1- WFPC2 IMAGE PC1-FIX F410M 2 50 S POS TARG +0.23,+0.115 PC1 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 121 LMC-N160A1- WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 120 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 122 LMC-N160A1- WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 120 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 123 LMC-N160A1- WFPC2 IMAGE PC1-FIX F300W 2 14 S SAME POS AS 120 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 130 LMC-N160A1- WFPC2 IMAGE PC1-FIX F410M 2 50 S POS TARG +0.115,+0.23 PC1 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 131 LMC-N160A1- WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 130 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 132 LMC-N160A1- WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 130 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 133 LMC-N160A1- WFPC2 IMAGE PC1-FIX F300W 2 14 S SAME POS AS 130 PC1 ------------------------------------------------------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 7] Visit: 02 Visit Priority: Visit Requirements: ORIENT 70D TO 180D On Hold Comments: Additional Comments: NEBULAR FILTERS, LMC-N160A1 CENTERED IN WF2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 200 LMC-N160A1- WFPC2 IMAGE WF2-FIX F656N 2 260 S WF2 ------------------------------------------------------------------------------------------------------------------------------------ 201 LMC-N160A1- WFPC2 IMAGE WF2-FIX F487N 2 260 S SAME POS AS 200 WF2 ------------------------------------------------------------------------------------------------------------------------------------ 202 LMC-N160A1- WFPC2 IMAGE WF2-FIX F502N 2 300 S SAME POS AS 200 WF2 ------------------------------------------------------------------------------------------------------------------------------------ 210 LMC-N160A1- WFPC2 IMAGE WF2-FIX F502N 2 300 S POS TARG +0.75,+0.75 WF2 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 211 LMC-N160A1- WFPC2 IMAGE WF2-FIX F487N 2 260 S SAME POS AS 210 WF2 ------------------------------------------------------------------------------------------------------------------------------------ 212 LMC-N160A1- WFPC2 IMAGE WF2-FIX F656N 2 260 S SAME POS AS 210 WF2 ------------------------------------------------------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 8] Visit: 03 Visit Priority: Visit Requirements: ORIENT +0D TO +150D On Hold Comments: Additional Comments: STELLAR FILTERS, LMC-N11A CENTERED IN PC1, BEST ROLL 70D Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 300 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F300W 2 14 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 301 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 300 1 ------------------------------------------------------------------------------------------------------------------------------------ 302 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 300 1 ------------------------------------------------------------------------------------------------------------------------------------ 303 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F410M 2 50 S SAME POS AS 300 1 ------------------------------------------------------------------------------------------------------------------------------------ 310 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F410M 2 50 S POS TARG +0.345,+0.345 1 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 311 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 310 1 ------------------------------------------------------------------------------------------------------------------------------------ 312 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 310 1 ------------------------------------------------------------------------------------------------------------------------------------ 313 LMC-N11A-PC WFPC2 IMAGE PC1-FIX F300W 2 14 S SAME POS AS 310 1 ------------------------------------------------------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 9] Visit: 04 Visit Priority: Visit Requirements: ORIENT 140D TO 170D On Hold Comments: Additional Comments: NEBULAR FILTERS, LMC-N11A CENTERED IN WF2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 400 LMC-N11A-WF WFPC2 IMAGE WF2-FIX F656N 2 260 S 2 ------------------------------------------------------------------------------------------------------------------------------------ 401 LMC-N11A-WF WFPC2 IMAGE WF2-FIX F487N 2 260 S SAME POS AS 400 2 ------------------------------------------------------------------------------------------------------------------------------------ 402 LMC-N11A-WF WFPC2 IMAGE WF2-FIX F502N 2 300 S SAME POS AS 400 2 ------------------------------------------------------------------------------------------------------------------------------------ 410 LMC-N11A-WF WFPC2 IMAGE WF2-FIX F502N 2 300 S POS TARG +0.75,+0.75 2 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 411 LMC-N11A-WF WFPC2 IMAGE WF2-FIX F487N 2 260 S SAME POS AS 410 2 ------------------------------------------------------------------------------------------------------------------------------------ 412 LMC-N11A-WF WFPC2 IMAGE WF2-FIX F656N 2 260 S SAME POS AS 410 2 ------------------------------------------------------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 10] Visit: 05 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: STELLAR FILTERS, LMC-N83B1 CENTERED IN PC1 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 500 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F300W 2 14 S C1 ------------------------------------------------------------------------------------------------------------------------------------ 501 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 500 C1 ------------------------------------------------------------------------------------------------------------------------------------ 502 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 500 C1 ------------------------------------------------------------------------------------------------------------------------------------ 503 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F410M 2 50 S SAME POS AS 500 C1 ------------------------------------------------------------------------------------------------------------------------------------ 510 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F410M 2 50 S POS TARG +0.345,+0.345 C1 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 511 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F467M 2 35 S SAME POS AS 510 C1 ------------------------------------------------------------------------------------------------------------------------------------ 512 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F547M 2 10 S SAME POS AS 510 C1 ------------------------------------------------------------------------------------------------------------------------------------ 513 LMC-N83B1-P WFPC2 IMAGE PC1-FIX F300W 2 14 S SAME POS AS 510 C1 ------------------------------------------------------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 11] Visit: 06 Visit Priority: Visit Requirements: ORIENT 155D TO 175D On Hold Comments: Additional Comments: NEBULAR FILTERS, LMC-N83B1 CENTERED IN WF2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 600 LMC-N83B1-W WFPC2 IMAGE WF2-FIX F656N 2 260 S F2 ------------------------------------------------------------------------------------------------------------------------------------ 601 LMC-N83B1-W WFPC2 IMAGE WF2-FIX F487N 2 260 S SAME POS AS 600 F2 ------------------------------------------------------------------------------------------------------------------------------------ 602 LMC-N83B1-W WFPC2 IMAGE WF2-FIX F502N 2 300 S SAME POS AS 600 F2 ------------------------------------------------------------------------------------------------------------------------------------ 610 LMC-N83B1-W WFPC2 IMAGE WF2-FIX F502N 2 300 S POS TARG +0.75,+0.75 F2 Comments: Implementing a default dither for filter sequence ------------------------------------------------------------------------------------------------------------------------------------ 611 LMC-N83B1-W WFPC2 IMAGE WF2-FIX F487N 2 260 S SAME POS AS 610 F2 ------------------------------------------------------------------------------------------------------------------------------------ 612 LMC-N83B1-W WFPC2 IMAGE WF2-FIX F656N 2 260 S SAME POS AS 610 F2 ------------------------------------------------------------------------------------------------------------------------------------ 8247( 3) - 11/09/99 16:05 - [ 12] Summary Form for Proposal 8247 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX WF2-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 335D TO 360D ORIENT 0D TO 145D SAME POS AS 100 POS TARG +0.345,+0.345 SAME POS AS 110 POS TARG +0.23,+0.115 SAME POS AS 120 POS TARG +0.115,+0.23 SAME POS AS 130 ORIENT 70D TO 180D SAME POS AS 200 POS TARG +0.75,+0.75 SAME POS AS 210 ORIENT +0D TO +150D SAME POS AS 300 SAME POS AS 310 ORIENT 140D TO 170D SAME POS AS 400 SAME POS AS 410 SAME POS AS 500 SAME POS AS 510 ORIENT 155D TO 175D SAME POS AS 600 SAME POS AS 610 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F300W F467M F547M F410M F656N F487N F502N ------------------------------------------------------------------------------------------------------------------------------------ Target Names LMC-N160A1-PC1 LMC-N160A1-WF2 LMC-N11A-PC1 LMC-N11A-WF2 LMC-N83B1-PC1 LMC-N83B1-WF2 ------------------------------------------------------------------------------------------------------------------------------------