9509( 6) - 03/03/03 11:06 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9509 Version: 6 Check-in Date: 03-Mar-2003 11:03:34 1.Proposal Title: Probing the Distance and Structure of the LMC Using Eclipsing Binaries: STIS Spectrophotometry ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Edward Guinan Villanova University CoI: Dr. Ignasi Ribas Villanova University N CoI: Dr. Edward Fitzpatrick Villanova University N CoI: Dr. Frank Maloney Villanova University N CoI: Dr. Jens Viggo Clausen Copenhagen University Observatory N ------------------------------------------------------------------------------------ 5. Abstract The distance to the LMC is crucial to calibrating the Cosmic Distance Scale but remains controversial and uncertain despite the efforts of many investigators. We have shown that the analysis of eclipsing binary (EB) systems has the potential to resolve this controversy. We have determined accurate distances to three eclipsing binaries in the LMC. Two EBs in the LMC bar, HV 2274 and EROS 1044, yield a consistent distance of 46.0+/-1.2 kpc for the bar itself. A third system, HV 982, is located at a greater distance (50.2+/-1.2 kpc), which is similar to that of the nearby SN 1987A (51.4+/-1.2 kpc). These results may suggest a significant depth to the LMC populations but a larger stellar sample is needed to verify this. The distances of the program stars were derived from ground-based light curves, HST or CTIO radial velocity data, and HST UV/optical spectrophotometry. We propose HST/STIS low-resolution spectra of seven LMC EBs for which we already have radial velocity and light curves. This will permit us to complete the analysis and derive accurate (to ~3%) individual distances. HST/STIS spectroscopy (covering 115-800nm) is a key dataset because it provides Teff, Fe/H, and A_lambda. The ensemble of targets, in addition to nailing down the distance to the LMC, will provide fundamental stellar properties and a detailed probe of the structure and spatial extent of this important galaxy, in particular its line-of-sight depth. ------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 2] Observations Description ------------------------ We wish to obtain complete low resolution spectral coverage, from 115 to 800 nm, for the seven targets. This will require the use of four different grating/detector combinations: G140L (STIS/FUV), G230L (STIS/NUV), G430L (STIS/CCD), and G750L (STIS/CCD). Continuous wavelength coverage from the UV to the near-IR (including the important B, V, and Balmer jump regions) has been proven to yield very accurate stellar and interstellar properties such as Teff, m/H, and A_lambda (see Fitzpatrick et al. 2001). These quantities are essential to derive reliable distances and to accomplish the major scientific goals of our project. According to the HST orbital constraints and the declination of our targets, a visibility of approximately 58 min is available per orbit. Simulations with the RPS2 software for the STIS instrument indicate that a total of 20 min of a visit's first orbit are not available for science because of guide star acquisition, small angle maneuvers, wavelength calibration and overheads. Using the online STIS exposure calculator, we have estimated the exposure times necessary to achieve a signal-to-noise ratio of at least 40:1 per resolution element. Our experience shows that at this S/N the spectrophotometry will have sufficient quality for the determination of the stellar parameters and reddenings. In our calculations, we have used the V magnitudes and spectral types of the components and assumed a typical LMC reddening of E(B-V)=0.12 mag. HST/FOS spectra are available for three of the targets and actual observed fluxes have been used to check the results. For the six brighter targets, a S/N~40 in all detector/grating combinations can be obtained in a single HST orbit. A typical visit will consist of a 380-s G140L exposure, followed by a 200-s G230L exposure, two 45-s G430L exposures, and two 75-s G750L exposures. Flat fields to correct for fringe patterns will be aquired immediately after the end of the visibility period to maximize scientifically-useful time. For the fainter target (LMC09-121729), a visit consisting of two orbits is required to achieve our S/N goal. In this case, the first, shorter orbit will be used to aquire spectra in the more efficient G430L and G750L gratings, and the G140L and G230L observations will be executed during the second orbit of the visit. The timing of the visits is weakly constrained, since we wish to observe the binaries outside of eclipses (phases 0.2-0.3 or 0.7-0.8). Real Time Justification ----------------------- It is important to the success of the program that these observations are obtained near the orbital quadratures (phases 0.2-0.3 or 0.7-0.8), when the two components are fully visible. At such phases the target is brighter and more flux is received so that and the achieved signal-to- noise ratio is maximized. In addition, little or no light variation will exist over the exposure time, thus simplifying the combination of the different wavelength portions into a single spectrum spanning 115 to 800 nm. Four of the six targets have eccentric orbits and so the actual quadratures may actually differ from phases 0.25 and 0.75. However, since all the light curves are available, the adequate phases to execute the spectrophotometric observations can be carefully selected. The ephemeris and orbital phases of secondary minimum for all targets are listed below: Target Min I Phi_Min II LMC-HV2241 HJD 2449477.7285+4.3426241 E 0.50 LMC-HV2274 HJD 2448099.818 +5.726006 E 0.49 LMC-HV12634 HJD 2446043.6693+1.18918778 E 0.50 LMC-MACHO0518 HJD 2449072.1704+3.107089 E 0.54 LMC-MACHO0509 HJD 2449071.5509+2.678781 E 0.49 LMC16-070662 HJD 2450741.0948+3.881922 E 0.51 LMC09-121729 HJD 2450459.2110+2.636580 E 0.53 BVRI photometry is planned for some of the EBs during 2002/2003 to refine the light curves but this does not have an impact on HST scheduling. The orbital and 9509( 6) - 03/03/03 11:06 - [ 3] Cepheid ephemerides for the target with a Cepheid component are: Min I (SC21 40876) = HJD2452057.64 + 397.142109 E Cep Max (SC21 40876) = HJD2450723.62189 + 4.98270 E Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LMC-HV12634 EXT-STAR, B0-B2 V-IV RA=05H 40M 57.24S +/- 1", DEC=- J2000 V = 15.2+/-0.1 71D 17' 52.7" +/- 1", PLATE- F(1400)=6.92+/-0.05e-14 ID=05ZW F(2300)=2.51+/-0.05e-14 F(4300)=6.17+/-0.05e-15 Coordinate Source: GSC_SURVEY_PLATE 2 LMC- EXT-STAR, B0-B2 V-IV RA=05H 18M 4.48S +/- 1", DEC=- J2000 V = 14.37+/-0.05 MACHO0518 69D 48' 19.9" +/- 1", PLATE- V-R = -0.14+/-0.05 ID=05ZW E(B-V) = 0.12+/-0.05 Coordinate Source: GSC_SURVEY_PLATE 3 LMC- EXT-STAR, B0-B2 V-IV RA=05H 9M 29.37S +/- 1", DEC=- J2000 V = 14.56+/-0.05 MACHO0509 68D 55' 2.6" +/- 1", PLATE- V-R = -0.22+/-0.05 ID=05ZW E(B-V) = 0.12+/-0.05 Coordinate Source: GSC_SURVEY_PLATE 4 LMC-OGLE16 EXT-STAR, B0-B2 V-IV RA=05H 35M 17.74S +/- 1", DEC=- J2000 V = 15.10+/-0.05 69D 43' 18.7" +/- 1", PLATE- V-I = 0.04+/-0.05 ID=06B0 E(B-V) = 0.12+/-0.05 Coordinate Source: GSC_SURVEY_PLATE 5 LMC-OGLE09 EXT-STAR, B0-B2 V-IV RA=05H 13M 23.98S +/- 1", DEC=- J2000 V = 15.8+/-0.05 69D 22' 49.2" +/- 1", PLATE- E(B-V) = 0.12+/-0.05 ID=05ZW Coordinate Source: GSC_SURVEY_PLATE 6 SC21-40876 EXT-STAR, B6-B9.5 III-I RA=05H 20M 25.13S +/- 1", DEC=- J2000 V = 14.6+/-0.1 70D 11' 8.92" +/- 1", PLATE- ID=05ZW Coordinate Source: GSC_SURVEY_PLATE 9509( 6) - 03/03/03 11:06 - [ 5] Visit: 01 Visit Priority: Visit Requirements: PERIOD 1.18918778 D AND ZERO-PHASE JD2446043.669300 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 LMC-HV12634 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 LMC-HV12634 STIS/F ACCUM 52X2 G140L 1425 1 426 S PHASE 0.2 TO 0.3 MAX DUR UV-MAM 100% A ------------------------------------------------------------------------------------------------------------------------------------ 30 LMC-HV12634 STIS/N ACCUM 52X2 G230L 2376 1 224 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 LMC-HV12634 STIS/C ACCUM 52X2 G430L 4300 CR-SPLIT=3 1 114 S MAX DUR 100% CD ------------------------------------------------------------------------------------------------------------------------------------ 50 LMC-HV12634 STIS/C ACCUM 52X2 G750L 7751 CR-SPLIT=3 1 168 S MAX DUR 100% CD ------------------------------------------------------------------------------------------------------------------------------------ 60 CCDFLAT STIS/C ACCUM 52X2 G750L 7751 2 1 S CD ------------------------------------------------------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 6] Visit: 02 Visit Priority: Visit Requirements: PERIOD 3.107089 D AND ZERO-PHASE JD2449072.170400 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 LMC-MACHO05 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2 S 18 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 LMC-MACHO05 STIS/F ACCUM 52X2 G140L 1425 1 380 S PHASE 0.2 TO 0.3 MAX DUR 18 UV-MAM 100% A ------------------------------------------------------------------------------------------------------------------------------------ 30 LMC-MACHO05 STIS/N ACCUM 52X2 G230L 2376 1 211 S MAX DUR 100% 18 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 LMC-MACHO05 STIS/C ACCUM 52X2 G430L 4300 CR-SPLIT=3 1 108 S MAX DUR 100% 18 CD ------------------------------------------------------------------------------------------------------------------------------------ 50 LMC-MACHO05 STIS/C ACCUM 52X2 G750L 7751 CR-SPLIT=3 1 150 S MAX DUR 100% 18 CD ------------------------------------------------------------------------------------------------------------------------------------ 60 CCDFLAT STIS/C ACCUM 52X2 G750L 7751 2 1 S CD ------------------------------------------------------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 7] Visit: 03 Visit Priority: Visit Requirements: PERIOD 2.678781 D AND ZERO-PHASE JD2449071.550900 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 LMC-MACHO05 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2 S 09 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 LMC-MACHO05 STIS/F ACCUM 52X2 G140L 1425 1 380 S PHASE 0.2 TO 0.3 MAX DUR 09 UV-MAM 100% A ------------------------------------------------------------------------------------------------------------------------------------ 30 LMC-MACHO05 STIS/N ACCUM 52X2 G230L 2376 1 211 S MAX DUR 100% 09 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 LMC-MACHO05 STIS/C ACCUM 52X2 G430L 4300 CR-SPLIT=3 1 108 S MAX DUR 100% 09 CD ------------------------------------------------------------------------------------------------------------------------------------ 50 LMC-MACHO05 STIS/C ACCUM 52X2 G750L 7751 CR-SPLIT=3 1 150 S MAX DUR 100% 09 CD ------------------------------------------------------------------------------------------------------------------------------------ 60 CCDFLAT STIS/C ACCUM 52X2 G750L 7751 2 1 S CD ------------------------------------------------------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 8] Visit: 04 Visit Priority: Visit Requirements: PERIOD 3.881922 D AND ZERO-PHASE JD2450741.094800 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 LMC-OGLE16 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 LMC-OGLE16 STIS/F ACCUM 52X2 G140L 1425 1 380 S PHASE 0.2 TO 0.3 MAX DUR UV-MAM 100% A ------------------------------------------------------------------------------------------------------------------------------------ 30 LMC-OGLE16 STIS/N ACCUM 52X2 G230L 2376 1 211 S MAX DUR 100% UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 LMC-OGLE16 STIS/C ACCUM 52X2 G430L 4300 CR-SPLIT=3 1 108 S MAX DUR 100% CD ------------------------------------------------------------------------------------------------------------------------------------ 50 LMC-OGLE16 STIS/C ACCUM 52X2 G750L 7751 CR-SPLIT=3 1 150 S MAX DUR 100% CD ------------------------------------------------------------------------------------------------------------------------------------ 60 CCDFLAT STIS/C ACCUM 52X2 G750L 7751 2 1 S CD ------------------------------------------------------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 9] Visit: 05 Visit Priority: Visit Requirements: PERIOD 2.636580 D AND ZERO-PHASE JD2450459.211000 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 LMC-OGLE09 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 LMC-OGLE09 STIS/N ACCUM 52X2 G230L 2376 1 1348 S PHASE 0.2 TO 0.3 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 30 LMC-OGLE09 STIS/C ACCUM 52X2 G430L 4300 CR-SPLIT=4 1 480 S MAX DUR 100% CD ------------------------------------------------------------------------------------------------------------------------------------ 40 LMC-OGLE09 STIS/F ACCUM 52X2 G140L 1425 1 1974 S MAX DUR 100% UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 LMC-OGLE09 STIS/C ACCUM 52X2 G750L 7751 CR-SPLIT=4 1 664 S MAX DUR 100% CD ------------------------------------------------------------------------------------------------------------------------------------ 60 CCDFLAT STIS/C ACCUM 52X2 G750L 7751 2 1 S CD ------------------------------------------------------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 10] Visit: 06 Visit Priority: Visit Requirements: PERIOD 4.98270 D AND ZERO-PHASE JD2450722.874880 BETWEEN 19-Apr-2003 AND 7- MAY-2003 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 SC21-40876 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 SC21-40876 STIS/C ACCUM 52X0.5E G430M 4451 CR-SPLIT=2 1 800 S PHASE 0.0 TO 0.05 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 30 SC21-40876 STIS/C ACCUM 52X0.5E G750M 8561 CR-SPLIT=2 1 1094 S CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 40 CCDFLAT STIS/C ACCUM 52X0.5E G750M 8561 2 5 S CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 11] Visit: 07 Visit Priority: Visit Requirements: PERIOD 4.98270 D AND ZERO-PHASE JD2450722.874880 BETWEEN 09-Apr-2003 AND 23-MAY-2003 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 SC21-40876 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 SC21-40876 STIS/C ACCUM 52X0.5E G430M 4451 CR-SPLIT=2 1 800 S PHASE 0.10 TO 0.15 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 30 SC21-40876 STIS/C ACCUM 52X0.5E G750M 8561 CR-SPLIT=2 1 1094 S CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 40 CCDFLAT STIS/C ACCUM 52X0.5E G750M 8561 2 5 S CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 9509( 6) - 03/03/03 11:06 - [ 12] Summary Form for Proposal 9509 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X2 52X0.5E1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT=3 CR-SPLIT=4 CR-SPLIT=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 1.18918778 D AND ZERO-PHASE JD2446043.669300 PHASE 0.2 TO 0.3 MAX DUR 100% MAX DUR 100% PERIOD 3.107089 D AND ZERO-PHASE JD2449072.170400 PERIOD 2.678781 D AND ZERO-PHASE JD2449071.550900 PERIOD 3.881922 D AND ZERO-PHASE JD2450741.094800 PERIOD 2.636580 D AND ZERO-PHASE JD2450459.211000 PHASE 0.2 TO 0.3 PERIOD 4.98270 D AND ZERO-PHASE JD2450722.874880 BETWEEN 19-Apr-2003 AND 7-MAY-2003 PHASE 0.0 TO 0.05 PERIOD 4.98270 D AND ZERO-PHASE JD2450722.874880 BETWEEN 09-Apr-2003 AND 23-MAY-2003 PHASE 0.10 TO 0.15 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L G230L G430L G750L G430M G750M ------------------------------------------------------------------------------------------------------------------------------------ Target Names LMC-HV12634 CCDFLAT LMC-MACHO0518 LMC-MACHO0509 LMC-OGLE16 LMC-OGLE09 SC21-40876 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 2376 4300 7751 4451 8561 ------------------------------------------------------------------------------------------------------------------------------------