Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1020c Report Date: 09-May-96:16:02 Version: ********** Check-in Date: ********** 1.Proposal Title: FAINT STARS AND GALAXIES IN SA 57 AND SA 68: FUTURE-CYCLE CONTINUATION ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR POPULATIONS GTO/OS Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. John N. Bahcall INSTITUTE FOR ADVANCED STUDY USA (609) 734-8054 DR. JOHN N. BAHCALL ------------------------------------------------------------------------------------ 7. Abstract Two selected area fields, one in SA 57 and one in SA 68, that have guide stars accessible for any telescope roll angle are proposed for study with deep WFC exposures. The results will compared with surveys of the same fields in x-ray, optical (from the ground), infrared, and radio wavelengths. The star counts will be used together with the Bahcall and Soneira Galaxy model to determine if the massive halo of the Galaxy is composed of stars that burn hydrogen. ST observations are required to discriminate between stars and galaxies at the faint magnitudes of interest. ------------------------------------------------------------------------------------ 8. Scientific Key Words: STAR COUNTS; STRUCTURE OF THE GALAXY; DEEP GALAXY COUNTS; GALAXY HALO ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.50 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOC WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1020c PI: Dr. John N. Bahcall Proposal Title: FAINT STARS AND GALAXIES IN SA 57 AND SA 68: FUTURE-CYCLE CONTINUATION ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Richard G. Kron CHICAGO, UNIVERSITY OF USA John N. Bahcall INSTITUTE FOR ADVANCED STUDY USA David C. Koo SPACE TELESCOPE SCIENCE USA INSTITUTE Donald Schneider INSTITUTE FOR ADVANCED STUDY USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Depending upon when HST launch occurs, we want the STScI Operations Branch to schedule one of the fields, either SA 57-1 or SA 68-1, for study during the Science Verification phase. The operations branch can decide which field is preferable based upon scheduling requirements, taking into account our need for dark time. If scheduling considerations are not decisive, use SA 57-1 as the program field. Two WFC exposures will be taken, one with F555W and one with F785LP, for the program field, SA 57-1 or SA 68-1. Dark time is required to reach the faint limiting magnitudes of interest. Since we want to measure colors for each of the objects in our program field, we would like to have the roll angle the same for both exposures. Parallel observations with the FOC/48 are requested to permit study of additional objects in the program field. Do SA 57-1 exposures in Cycle 1(SV) if it is accessible in the six months following ST launch. If not, do SA 68-1 exposures in Cycle 1(SV). ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. St observations are required in order to reach the faintest limiting magnitudes and to discriminate between stars and galaxies. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. Do the exposures for one of the fields during cycle 1(SV). The field positions have been chosen so that both fields have pe roll angle. The telescope roll angle should be the same for both exposures. The STScI operations branch can decide which field is preferable based upon scheduling requirements, taking into account our need for dark time. If scheduling considerations are not decisive, use SA 57- 1 as the program field. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Dark time is required to reach the faintest limiting magnitudes. We want a default cosmic ray exposure for each filter. We do not want other interruptions since the readout noise from additional exposures would decrease our limiting magnitude. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Data reduction and analysis will be performed at IAS, using the WFC image processing system developed by D. Schneider, and at STScI and the University of Chicago. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Survey results in other wavelength regions will be analyzed prior to ST launch and additional ground-based observations will be taken as required. The predictions of the Bahcall and Soneira Galaxy model will be computed for F555W and F785LP, with and without a massive hydrogen-burning halo, for differentassumed explorations of the spheroid luminosity function. Page 3 ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Support for data analysis, research assistance, and computing facilities will be supplied jointly by IAS, STScI, and the University of Chicago. ------------------------------------------------------------------------------------ 12. Two candidate primary fields are listed, SA 57-1 and SA 68-1. Only one of these two fields will be studied during the Science Verification phase. The operations branch of the STScI should decide which field better fits the schedule for science verification, depending upon the launch date of HST and the other science programs. If scheduling considerations are not decisive, use SA 57-1 as the program field. ------------------------------------------------------------------------------------ 13. Two selected area fields, one in SA 57 and one in SA 68, that have guide stars accessible for any telescope roll angle are proposed for study with deep WFC exposures. Parallel observations with the FOC/48 will be obtained. The results will be compared with surveys of the same fields in x-ray, optical(from the ground), infrared, and radio wavelengths. The star counts will be used together with the Bahcall and Soneira Galaxy model to determine if the massive halo of the Galaxy is composed of stars that burn hydrogen. Galaxy counts will determine if the simulated ST picture which has about 10E+2.5 galaxies (Bahcall 1985, IAU Symposium 113), based upon a conventional model of galaxy evolution, is a reasonable approximation. ------------------------------------------------------------------------------------ 11. Address Information Name: JOHN N. BAHCALL Category: PI Institution: INSTITUTE FOR ADVANCED STUDY Address: OLDEN LANE City: PRINCETON State: NJ Zip Code: 08540 Country: USA Telephone: (609) 734-8054 Telex (or e-mail): 837680 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1020c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 SA57-1 SURVEY FIELD IN SA57 RA = 13H 06M 52.22S +/- 1950 0.1S, DEC = +29D 28' 19.2" +/- 1" Comments: ONLY ONE OF THESE TARGETS WILL BE STUDIED. ------------------------------------------------------------------------------------------------------------------------------------ 2 SA68-1 SURVEY FIELD IN SA68 RA = 00H 15M 44.00S +/- ^ 0.1S, DEC = +15D 45' 45.0" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST c)Generic Targets ID = 1020c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 7 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Selection Criteria |Acqui|FLX| Flux data No | Name | Description | |Prblm|REF| | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 5 BG-OBJECTS PARALLEL (RANDOM) RANDOM FIELDS ACCESSIBLE WHEN WFC 8 FIELDS TO BE STUDIED STUDYING SA57-1 AND SA68-1 OFF SET 6.6' FROM SA57-1 Comments: WE WILL CHECK PARALLEL FIELDS ONCE SCHEDULING SPECIFIES ROLL ANGLE. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1020c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SA57-1 WFC IMAGE ALL F555W PRE-FLASH=YES 1 540S 2 DARK TIME / 1-2.1, CR-SPLIT=NO 5-6.1 CYCLE 4 / 1-6.1 NON-INT / 1-2.1,5- 6.1 Comments: ONLY ONE OF THE TARGETS, SA57-1 OR SA68-1, WILL BE STUDIED. ------------------------------------------------------------------------------------------------------------------------------------ 1.1 ^ ^ ^ ^ ^ PRE-FLASH=NO 1 2160S ^ SEQ 1-1.1 NO GAP CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 2 SA57-1 WFC IMAGE ALL F785LP PRE-FLASH=YES 1 540S 2 SAME ORIENT FOR 2 CR-SPLIT=NO AS 1 SEQ 2-2.1 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 2.1 ^ ^ ^ ^ ^ PRE-FLASH=NO 1 2160S ^ CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 5 SA68-1 WFC IMAGE ALL F555W PRE-FLASH=YES 1 540S 2 SELECT 1 OF 1-2.1 CR-SPLIT=NO OR 5-6.1 CONDITIONAL IF LAUNCH DATE ------------------------------------------------------------------------------------------------------------------------------------ 5.1 ^ ^ ^ ^ ^ PRE-FLASH=NO 1 2160S ^ SEQ 5-5.1 NO GAP CR-SPLIT=NO CONDITIONAL IF LAUNCH DATE ------------------------------------------------------------------------------------------------------------------------------------ 6 SA68-1 WFC IMAGE ALL F785LP PRE-FLASH=YES 1 540S 2 SAME ORIENT FOR 6 CR-SPLIT=NO AS 5 CONDITIONAL IF LAUNCH DATE ------------------------------------------------------------------------------------------------------------------------------------ 6.1 SA68-1 WFC IMAGE ALL F785LP PRE-FLASH=NO 1 2160S 2 SEQ 6-6.1 NO GAP CR-SPLIT=NO CONDITIONAL IF LAUNCH DATE ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1020c [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC ^ ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ^ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PRE-FLASH=YES CR-SPLIT=NO PRE-FLASH=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/OS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.50 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR POPULATIONS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements DARK TIME / 1-2.1,5-6.1 ; CYCLE 4 / 1-6.1; NON-INT / 1-2.1,5-6.1 SEQ 1-1.1 NO GAP SAME ORIENT FOR 2 AS 1 ; SEQ 2-2.1 NO GAP SELECT 1 OF 1-2.1 OR 5-6.1; CONDITIONAL IF LAUNCH DATE SEQ 5-5.1 NO GAP ; SAME ORIENT FOR 6 AS 5 ; SEQ 6-6.1 NO GAP ; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W ^ F785LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names SA57-1 SA68-1 BG-OBJECTS ------------------------------------------------------------------------------------------------------------------------------------