! File: 4247C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:18:56:32 coverpage: title_1: UV OBSERVATIONS OF GEMINGA sci_cat: STELLAR ASTROPHYSICS sci_subcat: NEUTRON STARS proposal_for: GO/DD pi_title: DR. pi_fname: STEPHEN pi_mi: S. pi_lname: HOLT pi_inst: NASA/GODDARD SPACE FLIGHT CENTER pi_country: USA pi_phone: (301) 286 6066 hours_pri: 1.50 num_pri: 1 hsp: Y pi_position: DIRECTOR CODE 600 off_fname: STEPHEN off_mi: S. off_lname: HOLT off_title: DIRECTOR CODE 600 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 off_telex: 36149 ! end of coverpage abstract: line_1: The gamma-ray source Geminga (identified with the X-ray line_2: source 1E0630+178) is a near-by neutron star detected as a 237 ms line_3: pulsar in both the X-ray and gamma-ray region of the spectrum line_4: (Halpern and Holt, 1992). It is not detected as a radio pulsar, line_5: however. We will observe the proposed optical counterpart of line_6: Geminga (star G" in the list of Halpern and Tytler, 1988) in the line_7: UV (140 - 300 nm) with the High Speed Photometer in an attempt to line_8: detect the 237 ms pulsation. An offset of 1.3 arcmin from GSC line_9: 01333.01169 will be required to acquire G". A positive detection line_10: of the 237 ms period will confirm the identity of G" as Geminga line_11: and extend our knowledge of the spectrum of a neutron star into line_12: the UV; a negative result may place important constraints on the line_13: standard model of neutron star emission. ! ! end of abstract general_form_proposers: lname: HOLT fname: STEPHEN title: PI mi: S. inst: NASA/GODDARD SPACE FLIGHT CENTER country: USA ! lname: KAZANAS fname: DEMOSTHENES inst: NASA/GODDARD SPACE FLIGHT CENTER country: USA ! lname: BIGGS fname: JAMES mi: D. inst: UNIVERSITIES SPACE RESEARCH ASSOCIATION country: USA ! lname: DOLAN fname: JOSEPH mi: F. inst: NASA/GODDARD SPACE FLIGHT CENTER country: USA ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: Candidate star G" will be acquired by offset of 1.8 arcmin from GSC line_2: 01333.01169. A 40 minute (one orbit) non-interrupted observation of G" will be line_3: obtained with 1 ms time resolution using the F140LP filter (140 - 300 nm) on line_4: the High Speed Photometer. The data will be searched for the signature of the line_5: 237 ms pulsar period from Geminga. ! question: 3 section: 1 line_1: The proposed observations require the following capabilities of HST: line_3: (1) High time resolution (1 ms) with no scintillation noise - line_4: necessary to obtain the highest signal-to-noise ratio possible in line_5: searching for a 237 ms period signal from a faint star. line_7: (2) Access to the UV (140 - 300 nm) - the spectrum of a neutron line_8: star is expected to be brighter in the UV than in the visible, line_9: and the UV spectrum of a pulsar is unobservable from the ground. ! question: 4 section: 1 line_1: The HSPSIM routine on the SCIVAX computer was used to simulate the count line_2: rate of star G" through the F140LP filter given the results obtained by the HSP line_3: Team on the Crab pulsar (time-averaged V = 16) through the same filter. Given line_4: V = 25.3 (Halpern and Tytler, 1988), we estimate 0.3 counts per second line_5: detected. 1 ms time resolution should allow us to detect any signal at a line_6: 237 ms period; the data can be co-added on the ground to produce coarser time line_7: bins if necessary for detection. A 40 minute, one-orbit observation would line_8: obtain 700 photons from the source, or a S/N of 25. This will allow us to line_9: detect any 237 ms signature in the signal with a pulsed fraction > 1%. It will line_10: also allow us to detect the presence of any unpulsed component of the flux if line_11: that component contains > 5% of the total flux. ! question: 5 section: 1 line_1: ! question: 6 section: 1 line_1: Standard data analysis techniques, including FFT analysis, will be carried line_2: out on the data using the standard packages developed and used on the Crab line_3: pulsar observations by the HSP Team at NASA Goddard Space Flight Center. ! question: 7 section: 1 line_1: ! question: 8 section: 1 line_1: Previous HST Time: line_2: GTO 1101 "Optical and UV Observations of Radio Pulsars" line_3: Establishes the Crab pulsar photometric light curve in the UV. line_4: Paper in preparation. ! question: 9 section: 1 line_1: Computing facilities will be supplied by home institution. ! !end of general form text general_form_address: lname: HOLT fname: STEPHEN mi: S. title: DR. category: PI inst: NASA/GODDARD SPACE FLIGHT CENTER addr_1: MAIL CODE 681 city: GREENBELT state: MD zip: 20771 country: USA phone: (301) 286 5920 from_date: 01-JAN-92 to_date: 31-DEC-93 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: GSC01333-01169 name_2: GEMINGA-OFFSET descr_1: A, 160 pos_1: RA = 06H 33M 49.14S +/- 0.02S, pos_2: DEC = +17D 47' 30.7" +/- 0.3" equinox: 2000 fluxnum_1: 1 fluxval_1: V=11.4 ! targnum: 2 name_1: GPRIMEPRIME name_2: GEMINGA-CANDIDATE descr_1: A,160 pos_1: RA = 06H 30M 59.06S +/- 0.02S, pos_2: DEC = +17D 48' 32.75" +/- 0.3" equinox: 1950 fluxnum_1: 1 fluxval_1: V=25.3 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: PHOT targname: GSC01333-01169 config: HSP/UV1 opmode: ACQ num_exp: 1 time_per_exp: 10S s_to_n: 15 fluxnum_1: 1 priority: 1 req_1: SEQ 1-2 NO GAP; req_2: ONBOARD ACQ FOR 2; comment_1: THIS IS THE OFFSET ACQ FOR 2 comment_2: OFFSET SLEW REQUIRED FROM comment_3: GSC01333.01169 TO GPRIMEPRIME ! linenum: 2.000 sequence_1: ^ sequence_2: ^ targname: GPRIMEPRIME config: HSP/UV1 opmode: SINGLE aperture: 1.0-C sp_element: F140LP num_exp: 1 time_per_exp: 40M s_to_n: 100 fluxnum_1: 1 priority: 1 param_1: SAMPLE-TIME=0.001 req_1: CYCLE 2; req_2: RT-ANALYSIS; comment_1: EXPOSURE TIME = 40M OR MAXIMUM comment_2: TIME POSSIBLE IN ONE ORBIT ! linenum: 3.000 sequence_1: USE PHOT req_1: CYCLE 2; ! ! end of exposure logsheet ! No scan data records found