! File: 2378C.PROP ! Database: PEPDB ! Date: 17-FEB-1994:05:41:20 coverpage: title_1: DETECTING THE NEUTRON STAR IN GAMMA-RAY BURSTERS sci_cat: STELLAR ASTROPHYSICS proposal_for: GO longterm: 2 pi_title: DR. pi_fname: BRADLEY pi_mi: E. pi_lname: SCHAEFER pi_inst: UNIVERSITIES SPACE RESEARCH ASSOCIATION pi_country: USA pi_phone: 301-286-6955 keywords_1: GAMMA-RAY BURSTERS hours_pri: 6.50 num_pri: 1 foc: Y time_crit: Y funds_amount: 4922 funds_length: 24 pi_position: DR. off_fname: JAMES off_mi: H. off_lname: TRAINOR off_title: DIRECTOR off_inst: NASA,GODDARD SPACE FLIGHT CENTER off_addr_1: CODE 600 off_city: GREENBELT off_state: MD off_zip: 20771 off_country: USA off_phone: 301-286-6066 ! end of coverpage abstract: line_1: The nature of the gamma-ray burst (GRB) phenomena remains a line_2: puzzle in spite of the wealth of observational data because no line_3: source object has been identified. Great effort has therefore line_4: already been expended in counterpart searches; yet, even at the line_5: limit of current technology, no counterpart is known. The line_6: unique ultraviolet imaging capabilities of HST allow for a line_7: qualitatively new type of search--where we seek emission from line_8: the neutron star component. If we can find a counterpart, we line_9: could for the first time measure distance and temperature. We line_10: would be likely to eliminate most of the many GRB models and line_11: provide a significant observational base for theory. Hence, line_12: we believe that an HST counterpart would represent the line_13: biggest advance in knowledge in this field since the discovery line_14: of GRB's. ! ! end of abstract general_form_proposers: lname: HURLEY fname: KEVIN title: DR. inst: CALIFORNIA, UNIVERSITY OF, BERKELEY country: USA ! lname: MOTCH fname: CHRISTIAN title: DR. inst: BESANCON OBSERVATORY country: FRANCE esa: Y ! lname: CLINE fname: THOMAS title: DR. mi: L. inst: NASA, GODDARD country: USA ! lname: PEDERSEN fname: HOLGER title: DR. inst: EUROPEAN SOUTHERN OBSERVATORY country: CHILE esa: Y ! lname: SCHAEFER fname: BRADLEY title: P.I. mi: E. inst: MARYLAND, UNIVERSITY OF country: USA ! lname: CHEVALIER fname: CLAUDE title: DR. inst: HAUTE PROVENCE OBSERVATORY country: FRANCE esa: Y ! lname: ILOVAISKY fname: S. title: DR. mi: A. inst: HAUTE PROVENCE OBSERVATORY country: FRANCE esa: Y ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Our program seeks to find a neutron star inside a gamma ray line_2: burster error region. We will identify the neutron star by means of line_3: its (1) colors, (2) proper motion, (3) parallax or (4) variability. line_4: The neutron star will be a hot point-source, hence, the counterpart line_5: is best found with ultraviolet imaging. This implies that our line_6: instrument of choice is the Faint Object Camera, since its ultraviolet line_7: sensitivity is much better than that of the WF/PC. The details of line_8: our planned exposures are designed to maximize our sensitivity to line_9: any of the above properties. line_10: We will observe through the F220W and F342W (=U bandpass) line_11: filters. The U filter was chosen to facilitate calibration and line_12: comparison of bright objects with ground based data. The F220W line_13: filter was chosen because its central wavelength is well separated line_14: from that of F342W, and because its red-leak is the smallest. The line_15: F220W filter also has the greatest sensitivity of the filters line_16: blueward of U--other than F195W, which has a bad red-leak. The line_17: relative exposure time between the two filters will be such that line_18: a Rayleigh-Jeans spectrum would be detected with equal signal-to- line_19: noise in both. line_20: We will obtain a number of frames at different epochs, so as line_21: to identify variability, proper motion, and parallax. At least line_22: one pair of exposures for each field should be taken near the line_23: quadratures with the Sun. ! question: 3 section: 2 line_1: Given the size of the GRB error region, we must use the FOC line_2: in its f/48 512 X 1024 zoom-on mode. line_3: With an exposure time of 1.0 hours in the U filter, we expect line_4: to reach U = 27.3. This will detect a 1000000K neutron star at 500 line_5: pc or a 50000K neutron star at 100pc. ! question: 4 section: 1 line_1: Our program requires three of HST's unique capabilities: line_2: (1) Ultraviolet Imaging--A neutron star is best detected in the UV. line_3: (2) High Resolution--HST's excellent angular resolution is line_4: required to reliably distinguish the point-like counterpart line_5: from faint and small galaxies. line_6: (3) Extreme Sensitivity--We have demonstrated that the counterparts line_7: are fainter than can be detected with ground-based telescopes. line_8: In all available wavelength regimes, we have pursued the search for line_9: counterparts to the limits of available technology. We have line_10: accumulated over 250 hours of integration on CCD cameras during line_11: dark time on large telescopes. One field was even found to be line_12: empty to a B and R magnitude of 25.3. We have spent 15 nights in line_13: searching for near infrared counterparts including two nights of line_14: infrared array time on a 4m telescope. IRAS data has been studied line_15: for far infrared counterparts. Fifty hours of VLA time has been line_16: used to search for radio counterparts. Ninety hours of line_17: integration has been obtained with Einstein and EXOSAT. Almost line_18: all of the above data was taken by the authors of this proposal. line_19: No counterparts have been identified. It is clear that new line_20: technology is needed. ! question: 5 section: 1 line_1: The calculations of sensitivity follow the information given line_2: in the FOC Instrument Handbook as modified by notes in the line_3: January 1986 and July 1988 Newsletters. We find that a 1-hour line_4: integration through the F342W filter will reach a U magnitude of line_5: 27.3, for a S/N ratio of 5. A one hour exposure through a F220W line_6: filter would have the same sensitivity for detecting a hot source. line_7: This sensitivity will detect a 1000000K neutron star at 500 pc or line_8: a 50000K neutron star at 100 pc. line_9: The multiple observations are required because variability, line_10: proper motion, or parallax are likely properties to identify the line_11: counterpart. The spacing of three observations over six month line_12: intervals is required to detect parallax and distinguish it from line_13: proper motion. line_14: The follow up observation is needed for close examination of line_15: any prospective counterpart, for example, through additional line_16: filters or to confirm variability. ! question: 6 section: 1 line_1: It is possible that GRB's may be close enough to exhibit line_2: measurable parallax. To this end, we need pairs of frames taken line_3: near the quadratures with the Sun. The length of the window for line_4: each observation is roughly one month. We request an additional line_5: observation roughly one year after the first pictures. This line_6: will be useful for long-term variability and for distinguishing line_7: parallax from proper motion. In addition, we space a pair of line_8: observations by several days to test for rapid variability. ! question: 7 section: 1 line_1: We would like the RSDP package to perform the standard line_2: calibrations. We would like to recieve the data both as FITS tapes line_3: of calibrated images and as black-and-white photographic line_4: representations. line_5: We expect that data analysis will use computers at NASA/ line_6: Goddard Space Flight Center and the European Coordinating line_7: Facility in Garching. The investigators at the GSFC also have the line_8: possibility of using the STScI computer. Initial analysis will line_9: use the DAOPHOT module of SDAS under IRAF. This routine will find line_10: images, then determine their centers, magnitudes, and shapes. line_11: Attention will be concentrated on the point-like sources. The line_12: astrometry for each image on all frames will be compared for line_13: parallax or proper motion. We will also examine the colors of line_14: each image and look for unusual features (e.g., jets). The line_15: observed sources outside the error boxes will be used to establish line_16: a statistical picture of the background. For bright objects or line_17: for red data, we will make reference to our extensive ground- line_18: based data. line_19: Our analysis will be carried out with great rapidity so line_20: that our follow-up targets can be optimally planned. ! question: 10 section: 1 line_1: The Goddard Space Flight Center has the IRAF system on a VAX 780 line_2: computer which will be used for data analysis. This computer also line_3: has a high resolution television screen with a hard copy unit. ! !end of general form text general_form_address: lname: SCHAEFER fname: BRADLEY mi: E. title: DR. category: PI inst: NASA/GSFC addr_1: CODE 661 city: GREENBELT state: MD zip: 20771 country: USA ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: STAR-163802-763709 name_2: 1944OT name_3: GRB790113 descr_1: STAR; NEUTRON STAR; GAMMA RAY pos_1: RA = 16H 31M 10.65S +/- 0.07S, pos_2: DEC = -76D 30' 50.8" +/- 0.2", equinox: 1950 fluxnum_1: 1 fluxval_1: V = 21.8 +/- 0.1 fluxnum_2: 2 fluxval_2: B-V = 1.5 +/- 0.7 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F220W num_exp: 1 time_per_exp: 15M priority: 1 param_1: PIXEL = 50X25 req_1: PERIOD 182.6D +/- 1D; req_2: ZERO-PHASE JD2448507 +/- 0.1D; req_3: PHASE 0.0 +/- 0.16; req_4: CYCLE 1 / 1-11 ! linenum: 2.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F342W num_exp: 1 time_per_exp: 15M priority: 1 param_1: PIXEL = 50X25 req_1: GROUP 1-2 NO GAP ! linenum: 3.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F220W num_exp: 1 time_per_exp: 15M priority: 2 param_1: PIXEL = 50X25 req_1: PHASE 0.0 +/- 0.16 OF REF 1; req_2: AFTER 1 BY 182.6D +/- 62D ! linenum: 4.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F342W num_exp: 1 time_per_exp: 15M priority: 2 param_1: PIXEL = 50X25 req_1: GROUP 3-4 NO GAP ! linenum: 5.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F220W num_exp: 1 time_per_exp: 15M priority: 3 param_1: PIXEL = 50X25 req_1: AFTER 3 BY 10D +/- 6D ! linenum: 6.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F342W num_exp: 1 time_per_exp: 15M priority: 3 param_1: PIXEL = 50X25 req_1: GROUP 5-8 NO GAP ! linenum: 7.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F430W num_exp: 1 time_per_exp: 10M priority: 3 param_1: PIXEL = 50X25 req_1: GROUP 5-8 NO GAP ! linenum: 8.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F195W num_exp: 1 time_per_exp: 11M priority: 3 param_1: PIXEL = 50X25 req_1: GROUP 5-8 NO GAP ! linenum: 9.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F220W num_exp: 1 time_per_exp: 15M priority: 3 param_1: PIXEL = 50X25 req_1: AFTER 3 BY 20D +/- 6D ! linenum: 10.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F342W num_exp: 1 time_per_exp: 15M priority: 3 param_1: PIXEL = 50X25 req_1: GROUP 9-11 NO GAP ! linenum: 11.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F195W num_exp: 1 time_per_exp: 14M priority: 4 param_1: PIXEL = 50X25 req_1: GROUP 9-11 NO GAP ! linenum: 100.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F220W num_exp: 1 time_per_exp: 15M priority: 2 param_1: PIXEL = 50X25 req_1: PHASE 0.0 +/- 0.16 OF REF 1.000; req_2: AFTER 1 BY 365.2D +/- 62D; req_3: CYCLE 2 / 100-101; req_4: COND IF TAC OK; ! linenum: 101.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F342W num_exp: 1 time_per_exp: 15M priority: 2 param_1: PIXEL = 50X25 req_1: GROUP 100-101 NO GAP; req_2: COND IF TAC OK; ! linenum: 102.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F220W num_exp: 1 time_per_exp: 42M priority: 3 param_1: PIXEL = 50X25 req_1: REQ UPDATE; req_2: CYCLE 2 / 102-103; req_3: AFTER 1 BY 450.0D; req_4: COND IF TAC OK; comment_1: CHOICE OF TIME, FILTER, EXPOSURE comment_2: DEPEND ON EARLY EXPOSURE RESULTS. ! linenum: 103.000 targname: STAR-163802-763709 config: FOC/48 opmode: IMAGE aperture: 512X1024 sp_element: F220W num_exp: 1 time_per_exp: 42M priority: 3 param_1: PIXEL = 50X25 req_1: REQ UPDATE; req_2: AFTER 1 BY 450.0D; req_3: COND IF TAC OK; comment_1: CHOICE OF TIME, FILTER, EXPOSURE comment_2: DEPEND ON EARLY EXPOSURE RESULTS. ! ! end of exposure logsheet ! No scan data records found