7891( 7) - 06/17/98 09:36 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7891 Version: 7 Check-in Date: 17-Jun-1998 09:34:57 1.Proposal Title: The Initial Mass Function of the Galactic Bulge ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: ALVIO RENZINI European Southern Observatory CoI: Alvio Renzini European Southern Observatory N CoI: Sergio Ortolani Universita di Padova N CoI: Laura Greggio Universita di Bologna N CoI: Jay A. Frogel The Ohio State University N CoI: Andrew Gould The Ohio State University N CoI: Ari Buchalter Columbia University N ------------------------------------------------------------------------------------ 5. Abstract We propose to measure the complete Galactic bulge luminosity function (LF) with signal-to-noise ratio 10 at H~eq 25, corresponding to M_H~eq 10.4 i.e., the end of the main sequence. This offers a unique clue to better understanding the complete stellar content, and hence the stellar mass-to- light ratio, of spiral bulges and by extension of ellipticals as well. This LF can be directly converted into an initial mass function (IMF) via the empirical mass-M_ H relation. This IMF will also allow one to clarify whether the excess of short duration microlensing events seen toward the bulge is due to low-mass stars or brown dwarfs or other more exotic objects. In addition the bulge LF can be directly compared with the LF in the solar neighborhood, and determine to which extent star formation at similar metallicities but radically different environmental conditions yields the same IMF. ------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 2] Observations Description ------------------------ As background fields at J and H are not required for NICMOS, our observations will be acquired in multiaccum mode with NIC2. From the NICMOS exposure time we get that 28, 200 s integration are required to reach H=25 (corresponding to 9.8* 10^-8 Jy) with S/N=10 in the F160W filter. Now, 10 orbits at 53 minutes per orbit gives us 31800 sec. Associated overheads are: initial guide star acquisition, repeated guide star acquisition, several multiaccum exposures on each orbit, and dithering a few pixels between each multiaccum. These overheads will fill in the rest of the time available on 10 orbits. Fine tuning can easily be done in phase 2 if this proposal is accepted. Thus, in 10 orbits we will be able to reach H=25 at our desired S/N=10. We estimate that the faintest stars will be at J=25.7, or at 9* 10^-8 Jy. The Exposure time calculator shows that with NIC2 and F110W we can reach this level with a S/N=10 in only 10, 000 s. With overheads as noted above and a small safety margin, we are requesting 4 orbits for the J band F110W observations. Although NIC1 can achieve somewhat higher spatial resolution, a factor of two more integration time would be required. Data that we obtain with NIC1 J band F110W while observing with NIC2 will be of value in assessing the crowding problems. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: DAT Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558- STELLAR CLUSTER, BULGE RA=18H 11M 03.8S +/- 0.1S, DEC=- J2000 V = 20.0+/-0.1 FIELD-1 31D 45' 49.1" +/- 0.2", PLATE- ID=067O Comments: Center of field 2 NGC6558- STELLAR CLUSTER, BULGE RA=18H 11M 03.84S +/- 0.1S, DEC= J2000 V = 20.0+/-0.1 FIELD-2 -31D 45' 48.6" +/- 0.2", PLATE- ID=067O Comments: Offset 0.04s E, 0.5" N 3 NGC6558- STELLAR CLUSTER, BULGE RA=18H 11M 03.76S +/- 0.1S, DEC= J2000 V = 20.0+/-0.1 FIELD-3 -31D 45' 48.6" +/- 0.2", PLATE- ID=067O Comments: Offset 0.04s W, 0.5" N 4 NGC6558- STELLAR CLUSTER, BULGE RA=18H 11M 03.76S +/- 0.1S, DEC= J2000 V = 20.0+/-0.1 FIELD-4 -31D 45' 49.6" +/- 0.2", PLATE- ID=067O Comments: Offset 0.04s W, 0.5" S 5 NGC6558- STELLAR CLUSTER, BULGE RA=18H 11M 03.84S +/- 0.1S, DEC= J2000 V = 20.0+/-0.1 FIELD-5 -31D 45' 49.6" +/- 0.2", PLATE- ID=067O Comments: Offset 0.04s E, 0.5" S 7891( 7) - 06/17/98 09:36 - [ 4] Visit: 01 Visit Priority: Visit Requirements: SCHED 80% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558-FIE NIC2 MULTIAC NIC2 F110W CAMERA-FOCUS=1-2, 1 DEF PAR 2-3 WITH 1 LD-2 CUM PATTERN=SPIRAL-DITH,NUM-POS=8, OFFSET=SAM,DITH-SIZE=0.4, PATTERN-ORIENT=DETECTOR, SAMP-SEQ=STEP64,NSAMP=18 Comments: J band; spans 2 orbits ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 F110W SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: J band (Parallel NIC1) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC3 MULTIAC NIC3 F222M SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: K band (Parallel NIC3) ------------------------------------------------------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 5] Visit: 02 Visit Priority: Visit Requirements: SCHED 80% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558-FIE NIC2 MULTIAC NIC2 F110W CAMERA-FOCUS=1-2, 1 DEF PAR 2-3 WITH 1 LD-4 CUM PATTERN=SPIRAL-DITH,NUM-POS=8, OFFSET=SAM,DITH-SIZE=0.4, PATTERN-ORIENT=DETECTOR, SAMP-SEQ=STEP64,NSAMP=18 Comments: J band; spans 2 orbits ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 F110W SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: J band (Parallel NIC1) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC3 MULTIAC NIC3 F222M SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: K band (Parallel NIC3) ------------------------------------------------------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 6] Visit: 03 Visit Priority: Visit Requirements: SCHED 80% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558-FIE NIC2 MULTIAC NIC2 F160W CAMERA-FOCUS=1-2, 1 DEF PAR 2-3 WITH 1 LD-1 CUM PATTERN=SPIRAL-DITH,NUM-POS=8, OFFSET=SAM,DITH-SIZE=0.4, PATTERN-ORIENT=DETECTOR, SAMP-SEQ=STEP64,NSAMP=18 Comments: H band; spans 2 orbits ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 F110W SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: J band (Parallel NIC1) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC3 MULTIAC NIC3 F222M SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: K band (Parallel NIC3) ------------------------------------------------------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 7] Visit: 04 Visit Priority: Visit Requirements: SCHED 80% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558-FIE NIC2 MULTIAC NIC2 F160W CAMERA-FOCUS=1-2, 1 DEF PAR 2-3 WITH 1 LD-2 CUM PATTERN=SPIRAL-DITH,NUM-POS=8, OFFSET=SAM,DITH-SIZE=0.4, PATTERN-ORIENT=DETECTOR, SAMP-SEQ=STEP64,NSAMP=18 Comments: H band; spans 2 orbits ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 F110W SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: J band (Parallel NIC1) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC3 MULTIAC NIC3 F222M SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: K band (Parallel NIC3) ------------------------------------------------------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 8] Visit: 05 Visit Priority: Visit Requirements: SCHED 80% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558-FIE NIC2 MULTIAC NIC2 F160W CAMERA-FOCUS=1-2, 1 DEF PAR 2-3 WITH 1 LD-3 CUM PATTERN=SPIRAL-DITH,NUM-POS=8, OFFSET=SAM,DITH-SIZE=0.4, PATTERN-ORIENT=DETECTOR, SAMP-SEQ=STEP64,NSAMP=18 Comments: H band; spans 2 orbits ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 F110W SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: J band (Parallel NIC1) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC3 MULTIAC NIC3 F222M SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: K band (Parallel NIC3) ------------------------------------------------------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 9] Visit: 06 Visit Priority: Visit Requirements: SCHED 80% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558-FIE NIC2 MULTIAC NIC2 F160W CAMERA-FOCUS=1-2, 1 DEF PAR 2-3 WITH 1 LD-4 CUM PATTERN=SPIRAL-DITH,NUM-POS=8, OFFSET=SAM,DITH-SIZE=0.4, PATTERN-ORIENT=DETECTOR, SAMP-SEQ=STEP64,NSAMP=18 Comments: H band; spans 2 orbits ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 F110W SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: J band (Parallel NIC1) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC3 MULTIAC NIC3 F222M SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: K band (Parallel NIC3) ------------------------------------------------------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 10] Visit: 07 Visit Priority: Visit Requirements: SCHED 80% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6558-FIE NIC2 MULTIAC NIC2 F160W CAMERA-FOCUS=1-2, 1 DEF PAR 2-3 WITH 1 LD-5 CUM PATTERN=SPIRAL-DITH,NUM-POS=8, OFFSET=SAM,DITH-SIZE=0.4, PATTERN-ORIENT=DETECTOR, SAMP-SEQ=STEP64,NSAMP=18 Comments: H band; spans 2 orbits ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 F110W SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: J band (Parallel NIC1) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC3 MULTIAC NIC3 F222M SAMP-SEQ=STEP64,NSAMP=18 1 DEF CUM Comments: K band (Parallel NIC3) ------------------------------------------------------------------------------------------------------------------------------------ 7891( 7) - 06/17/98 09:36 - [ 11] Summary Form for Proposal 7891 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures NIC2 NIC1 NIC3 ------------------------------------------------------------------------------------------------------------------------------------ Configurations NIC2 NIC1 NIC3 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CAMERA-FOCUS=1-2 PATTERN=SPIRAL-DITH NUM-POS=8 OFFSET=SAM DITH-SIZE=0.4 PATTERN-ORIENT=DETECTOR SAMP-SEQ=STEP64 NSAMP=18 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 80% PAR 2-3 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W F222M F160W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC6558-FIELD-2 ANY NGC6558-FIELD-4 NGC6558-FIELD-1 NGC6558-FIELD-3 NGC6558-FIELD-5 ------------------------------------------------------------------------------------------------------------------------------------