5839( 5) - 03/13/96 12:11 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5839 Version: 5 Check-in Date: 13-Mar-1996 11:51:34 1.Proposal Title: GAMMA RAY BURST COUNTERPARTS IN THE ULTRAVIOLET ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Hot Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Prof. Bradley E. Schaefer Department of Physics, Yale University CoI: Dr. Thomas Cline Goddard Space Flight Center N CoI: Dr. Kevin Hurley University of California at Berkeley N ------------------------------------------------------------------------------------ 6. Abstract The nature of the Gamma Ray Burst (GRB) phenomenon remains a puzzle in spite of the wealth of observational data because no source object has been identified. Great effort has therefore already been expended in ground- based counterpart searches in the optical, infrared, and radio; yet, even at the limit of current technology, no counterpart is known. The unique ultraviolet imaging capabilities of HST allow for a qualitatively new type of search. While searching this new area of parameter space, we might find emission from hot neutron stars, hot accretion columns, or quasar hosts for the burster. If we find a counterpart, our analysis will depend on what we find, but it is likely that we might provide the first distance measure to a GRB as well as identify the nature of the bursting system. Hence, we believe that an HST counterpart would represent the biggest advance in knowledge in this field since the discovery of GRBs. ------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 2] Observations Description ------------------------ We will use the WFPC2, since the largest field-of-view for the FOC is 14"X14". Thus we will trade off the somewhat poorer UV sensitivity of the WFPC2 to be able to cover the GRB error box without large scale mosaics. Only four classical GRB boxes are small enough to fit into a WFPC2 field-of-view; GRB790406, GRB790613, GRB790325B, and GRB920406. The boxes have areas of 0.26, 0.76, 2.0 and 1.0 square arc-minutes. The size of the last region may be reduced (within four months) with further and tedious analysis of burst timings. We particularly value this latest box as its young age allows us to probe closer in time to the burst and perhaps catch a slowly cooling counterpart. Fortunately, each of these error boxes is away from the Milky Way (galactic latitudes of -61^degrees, +37^degrees, +21^degrees, and -28^degrees) so that crowded and absorbed regions near the Milky Way are avoided. We will observe each of these four GRBs on two visits, spaced by half-a- year so that parallax, proper motion, and long term variability can be detected. Short term variability can also be detected by comparisons between the CR-SPLIT images. Each field will be imaged through three filters, so as to allow for source classification based in part on color-color diagrams. The three filters that we have chosen are F439W, F336W, and F218W. The first two are for Johnson B and U which can be directly related to standard photometry. The third filter is the UV filter with the smallest red leak. The integration times will be distributed between the three filters such that a source with a Rayleigh-Jeans spectrum will be detected with equal significance in each filter. This implies that the F218W observations will be roughly twice as long as the F336W and F439W exposures. We are asking for two orbits for each visit, which will allow for a 40 minute exposure in F218W and 20 minutes in the other two filters. The calculated threshold for the U filter is roughly 26 magnitude. Real Time Justification ----------------------- It is possible that GRBs may be close enough to exhibit measurable parallax or proper motion. For both possibilities, we need images separated in time, with the optimal time being near the quadratures with the Sun. The length for each observing window is roughly one month. Having time separated observations also allows for a test of variability which could distinguish the counterpart. Calibration Justification ------------------------- Our calibration requirements are fairly weak since photon statistics dominate over calibration uncertainties in a detection experiment. Variability searches will be done differentially, so no calibration is required for this aspect of our program. The color-color diagrams will be used primarily for classification, so a photometric accuracy of roughly 0.1 magnitudes is adequate. The U and B filters will be separately calibrated for many other programs. So our only special calibration requirement may be an approximate measure of the sensitivity through the F218W filter. Our HST proposal is entirely self contained. However, the science will be supplemented by ground based observations in the optical. Specifically, we have obtained photometry of field stars in the U and B to provide calibrated standards. We have already obtained deep V and R images which can measure or constrain the spectral flux distribution of sources detected in the UV by HST. In addition, we have already looked at all four fields deep in the radio (Schaefer et al., 1989, Ap.J., 340, 455 and Palmer et al., 1993, Second Huntsville GRB Conference) and deep in the infrared (Schaefer et al., 1987, Ap.J., 313, 226 and Schaefer et al., 1993, Second Huntsville GRB Conference). Additional Comments ------------------- ------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GRB790406 STAR, Gamma Ray Burster RA = 23H 11M 12S +/- 21", DEC = 1950 -49D 55' 39" +/- 15", REGION 2 GRB790613 STAR, Gamma Ray Burster RA = 14H 12M 28.3S +/- 66", DEC 1950 = +78D 55' 19" +/- 84", REGION 3 GRB790325B STAR, Gamma Ray Burster RA = 18H 09M 53S +/- 34", DEC = 1950 +31D 23' 33" +/- 75", REGION Comments: A fifth mag star (104 Her) is at 18H 10M 01S +31D 23' 30" 1950 4 GRB920406 STAR, Gamma Ray Burster RA = 19H 16M 09.1S +/- 52", DEC 2000 = -57D 36' 30" +/- 80", REGION 5839( 5) - 03/13/96 12:11 - [ 5] Visit: 01 Visit Requirements: BETWEEN JD2450010 AND JD2450070 On Hold Comments: Additional Comments: Look at elongation for possibility of finding parallax Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GRB790406 WFPC2 IMAGE WFALL- F218W 1 39M FIX ------------------------------------------------------------------------------------------------------------------------------------ 2 GRB790406 WFPC2 IMAGE WFALL- F336W 1 22M FIX ------------------------------------------------------------------------------------------------------------------------------------ 3 GRB790406 WFPC2 IMAGE WFALL- F439W 1 18M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 6] Visit: 02 Visit Requirements: BETWEEN JD2450191 AND JD2450251 On Hold Comments: Additional Comments: Look at elongation for possibility of finding parallax Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 4 GRB790406 WFPC2 IMAGE WFALL- F218W 1 39M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5 GRB790406 WFPC2 IMAGE WFALL- F336W 1 22M FIX ------------------------------------------------------------------------------------------------------------------------------------ 6 GRB790406 WFPC2 IMAGE WFALL- F439W 1 18M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 7] Visit: 03 Visit Requirements: ORIENT 107D TO 147D On Hold Comments: Additional Comments: The GRB error box is long and thin, with the box going from the NNE to the SSW. The box extends along with the long direction at an angle of 37 degrees from North to East. I want the error box to extend along the U2 axis, which is the longest available. This GRB has high ecliptic latitude, so it matters little when the first observation is made. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 7 GRB790613 WFPC2 IMAGE WFALL- F218W 1 46M FIX ------------------------------------------------------------------------------------------------------------------------------------ 8 GRB790613 WFPC2 IMAGE WFALL- F336W 1 22M FIX ------------------------------------------------------------------------------------------------------------------------------------ 9 GRB790613 WFPC2 IMAGE WFALL- F439W 1 20M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 8] Visit: 04 Visit Requirements: AFTER 3 BY 130D TO 230D; ORIENT 287D TO 327D On Hold Comments: Additional Comments: The GRB error box is long and thin, with the box going from the NNE to the SSW. The box extends along with the long direction at an angle of 37 degrees from North to East. I want the error box to extend along the U2 axis, which is the longest available. This GRB has a high ecliptic latitude. So the primary need is to separate visits 3 and 4 by roughly six months so that parallax can be measured. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 GRB790613 WFPC2 IMAGE WFALL- F218W 1 46M FIX ------------------------------------------------------------------------------------------------------------------------------------ 11 GRB790613 WFPC2 IMAGE WFALL- F336W 1 22M FIX ------------------------------------------------------------------------------------------------------------------------------------ 12 GRB790613 WFPC2 IMAGE WFALL- F439W 1 20M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 9] Visit: 05 Visit Requirements: BETWEEN JD2449948 AND JD2450028; ORIENT 73D TO 106D On Hold Comments: Additional Comments: Look at elongation for possibility of finding parallax. Error box is a rhombus with the longest dimension being 151" within a degree of the North/South line. So the ORIENT command is to prevent parts of the box spilling outside the WFPC2 FOV. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 13 GRB790325B WFPC2 IMAGE WFALL- F218W 1 38M FIX ------------------------------------------------------------------------------------------------------------------------------------ 14 GRB790325B WFPC2 IMAGE WFALL- F336W 1 19M FIX ------------------------------------------------------------------------------------------------------------------------------------ 15 GRB790325B WFPC2 IMAGE WFALL- F439W 1 19M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 10] Visit: 06 Visit Requirements: BETWEEN JD2450127 AND JD2450207; ORIENT 253D TO 286D On Hold Comments: Additional Comments: Look at elongation for possibility of finding parallax Error box is a rhombus with the longest dimension being 151" within a degree of the North/South line. So the ORIENT command is to prevent parts of the box spilling outside the WFPC2 FOV. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 16 GRB790325B WFPC2 IMAGE WFALL- F218W 1 38M FIX ------------------------------------------------------------------------------------------------------------------------------------ 17 GRB790325B WFPC2 IMAGE WFALL- F336W 1 19M FIX ------------------------------------------------------------------------------------------------------------------------------------ 18 GRB790325B WFPC2 IMAGE WFALL- F439W 1 19M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 11] Visit: 07 Visit Requirements: BETWEEN JD2449967 AND JD2450027; ORIENT 44D TO 84D On Hold Comments: Additional Comments: The GRB error box is long and thin, with the box going from the NNW to the SSE. The box extends along with the long direction at an angle of 26 degrees from North to WEST. I want the error box to extend along the U2 axis, which is the longest available. Look at elongation for possibility of finding parallax Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 19 GRB920406 WFPC2 IMAGE WFALL- F218W 1 39M FIX ------------------------------------------------------------------------------------------------------------------------------------ 20 GRB920406 WFPC2 IMAGE WFALL- F336W 1 20M FIX ------------------------------------------------------------------------------------------------------------------------------------ 21 GRB920406 WFPC2 IMAGE WFALL- F439W 1 19M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 12] Visit: 08 Visit Requirements: BETWEEN JD2450146 AND JD2450206; ORIENT 224D TO 264D On Hold Comments: Additional Comments: The GRB error box is long and thin, with the box going from the NNW to the SSE. The box extends along with the long direction at an angle of 26 degrees from North to WEST. I want the error box to extend along the U2 axis, which is the longest available. Look at elongation for possibility of finding parallax Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 22 GRB920406 WFPC2 IMAGE WFALL- F218W 1 39M FIX ------------------------------------------------------------------------------------------------------------------------------------ 23 GRB920406 WFPC2 IMAGE WFALL- F336W 1 20M FIX ------------------------------------------------------------------------------------------------------------------------------------ 24 GRB920406 WFPC2 IMAGE WFALL- F439W 1 19M FIX ------------------------------------------------------------------------------------------------------------------------------------ 5839( 5) - 03/13/96 12:11 - [ 13] Summary Form for Proposal 5839 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Hot Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN JD2450010 AND JD2450070 BETWEEN JD2450191 AND JD2450251 ORIENT 107D TO 147D AFTER 3 BY 130D TO 230D; ORIENT 287D TO 327D BETWEEN JD2449948 AND JD2450028; ORIENT 73D TO 106D BETWEEN JD2450127 AND JD2450207; ORIENT 253D TO 286D BETWEEN JD2449967 AND JD2450027; ORIENT 44D TO 84D BETWEEN JD2450146 AND JD2450206; ORIENT 224D TO 264D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F218W F336W F439W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GRB790406 GRB790613 GRB790325B GRB920406 ------------------------------------------------------------------------------------------------------------------------------------