7966( 12) - 06/10/98 10:47 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7966 Version: 12 Check-in Date: 10-Jun-1998 10:46:16 1.Proposal Title: A Search for the Host Galaxy of GRB 970508 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO/DD 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: ANDREW FRUCHTER Space Telescope Science Institute CoI: Patrizia Caraveo IFCTR-CNR, Via Bassini 15, I-20133 Milan, N Italy CoI: Elena Pian ITESRE-CNR, Via Gobetti 101, I-40129 N Bologna, Italy CoI: Kailash Sahu STScI, 3700 San Martin Drive, Baltimore, N MD 21218 CoI: Mario Livio STScI, 3700 San Martin Drive, Baltimore, N MD 21218 CoI: Larry Petro STScI, 3700 San Martin Drive, Baltimore, N MD 21218 CoI: Duccio Macchetto STScI, 3700 San Martin Drive, Baltimore, N MD 21218 CoI: Harry Ferguson STScI, 3700 San Martin Drive, Baltimore, N MD 21218 CoI: Steve Thorsett Joseph Henry Labs., Dept of Physics, N Princeton Univ. Jadwin Hall, P.O. Box 708, CoI: Filippo Frontera ITESRE-CNR, Via Gobetti 101, I-40129 N Bologna, Italy CoI: Marco Tavani Columbia Astrophysics Lab., Columbia N Univ., New York, NY 10027 CoI: Eliana Palazzi ITESRE-CNR, Via Gobetti 101, I-40129 N Bologna, Italy 7966( 12) - 06/10/98 10:47 - [ 2] ------------------------------------------------------------------------------------ 5. Abstract We propose to reobserve the gamma-ray burster GRB970508 using the STIS CCD. Although this object was observed one month after burst by HST (Pian et al. 1998), neither the HST observations nor subsequent ground-based observations have shown direct evidence for a host galaxy. However, unusually strong Mg I absorption and O[II] emission found in Keck spectra (Metzger et al. 1997a, b) suggest that we are not observing a random line of sight through an intervening galaxy's halo, but rather that the GRB itself is found in a relatively dense, largely neutral, interstellar medium. At the time of re-observation, the optical transient (OT) associated with GRB970508 should be more than three magnitudes fainter than during the previous HST visit, allowing a far deeper search for the host galaxy. HST observations of the first optically identified GRB, GRB970228, show that the GRB lies in a host galaxy, and Keck observations of GRB971214 suggest the same may be true for that object. If we detect a galaxy at the position of GRB970508, then it will appear likely that all three optically identified BeppoSAX bursts lie in host galaxies -- a result that would require either that the sources of GRBs always lie in hosts, or that the afterglows of GRBs can only be observed when the bursts occur in a dense medium. In addition, if GRBs are always found in hosts, their position inside those hosts could provide important clues to the nature of the burst source. ------------------------------------------------------------------------------------ Observations Description ------------------------ See Above. Real Time Justification ----------------------- No RT. Calibration Justification ------------------------- The PSF star will be observed to better allow subtraction of the GRB that is embedded in the host galaxy. Additional Comments ------------------- None. ------------------------------------------------------------------------------------ Data Distribution Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7966( 12) - 06/10/98 10:47 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GRB970508 EXT-STAR, Gamma Ray RA=06H 53M 49.3S +/- 0.01S, J2000 V = 25+/-1 Burster DEC=79D 16' 19" +/- 0" 2 GRB970508- CALIBRATION, Point RA=06H 53M 32.23S +/- 0.01S, J2000 V = 15+/-1 PSF Spread Function DEC=79D 15' 21" +/- 0" 7966( 12) - 06/10/98 10:47 - [ 4] Visit: 01 Visit Priority: Visit Requirements: 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 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.0000, 0.0000 CD MAX DUR SEQ 10-16 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 11 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.2550, 0.1275 CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 15 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.0000, 0.0000 SF CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 16 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.2550, 0.1275 SF CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 20 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.3825, 0.3825 SF CD MAX DUR SEQ 20-26 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 21 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.1275, 0.2550 SF CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 25 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.3825, 0.3825 CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 26 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.1275, 0.2550 CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 30 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.2545, 0.3820 CD MAX DUR SEQ 30-36 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 31 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.5095, 0.5095 CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 35 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.2545, 0.3820 SF CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 36 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.5095, 0.5095 SF CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 40 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.3820, 0.2545 SF CD MAX DUR SEQ 40-46 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 41 GRB970508-P STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 15 S POS TARG 0.1270, 0.1270 SF CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 45 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.3820, 0.2545 CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 7966( 12) - 06/10/98 10:47 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 46 GRB970508 STIS/C ACCUM 50CCD MIRROR CR-SPLIT=NO 1 1446 S POS TARG 0.1270, 0.1270 CD MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 7966( 12) - 06/10/98 10:47 - [ 6] Summary Form for Proposal 7966 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 50CCD ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG 0.0000, 0.0000 MAX DUR SEQ 10-16 NON-INT POS TARG 0.2550, 0.1275 MAX DUR POS TARG 0.0000, 0.0000 MAX DUR POS TARG 0.3825, 0.3825 MAX DUR SEQ 20-26 NON-INT POS TARG 0.1275, 0.2550 MAX DUR POS TARG 0.3825, 0.3825 MAX DUR POS TARG 0.2545, 0.3820 MAX DUR SEQ 30-36 NON-INT POS TARG 0.5095, 0.5095 MAX DUR POS TARG 0.2545, 0.3820 MAX DUR POS TARG 0.3820, 0.2545 MAX DUR SEQ 40-46 NON-INT POS TARG 0.1270, 0.1270 MAX DUR POS TARG 0.3820, 0.2545 MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names GRB970508 GRB970508-PSF ------------------------------------------------------------------------------------------------------------------------------------