! $Id: 5497,v 5.1 1994/07/27 18:38:58 pepsa Exp $ coverpage: title_1: SPECTROSCOPIC IDENTIFICATION OF CANDIDATE CATACLYSMIC VARIABLE STARS title_2: NEAR THE CENTER OF THE POST-CORE-COLLAPSE GLOBULAR CLUSTER NGC 6397: CYCLE4 HIGH sci_cat: HOT STARS sci_subcat: X-RAY BINARIES proposal_for: GO longterm: 1 pi_fname: JONATHAN pi_mi: E pi_lname: GRINDLAY pi_inst: 2170 pi_country: USA pi_phone: 617-495-7204 hours_pri: 5.12 num_pri: 3 fos: Y off_title: ASSOC DIR AWARDS MGT off_inst: 2170 off_addr_1: PRESIDENT AND FELLOWS OF HARVARD COLLEGE off_addr_2: OFFICE OF SPONSORED RESEARCH off_addr_3: HOLYOKE CENTER 441 off_city: CAMBRIDGE off_state: MA off_zip: 02138 off_country: USA off_phone: 617-495-5501 ! end of coverpage abstract: line_1: We propose to obtain FOS spectra of three candidate cataclysmic variables line_2: (CVs) near the center of the nearby post-core-collapse globular cluster line_3: NGC 6397. These objects are located in the error circles of faint x-ray line_4: sources discovered with the ROSAT High Resolution Imager (HRI), and thus line_5: represent possible optical counterparts. We discovered these CV line_6: candidates in an imaging study of NGC 6397 in H-alpha and "R" filters line_7: performed with the HST Planetary Camera (PC). Photometry we have line_8: performed of the roughly 2200 stars in the PC field indicates that these line_9: three stars have absolute magnitudes and H-alpha emission line strengths line_10: typical of CVs. These stars also have the UV-excesses expected of CVs, line_11: as determined from a comparison of the PC data to several archival line_12: HST-FOC images of the cluster in UV filters. These objects are line_13: excellent candidates to be the long-sought CVs in globular clusters; line_14: spectroscopy is required to test this hypothesis. Due to the extreme line_15: crowding at the center of NGC 6397, spectroscopy of these faint line_16: candidates requires the angular resolution provided by HST. This study, line_17: which represents the final stage of our efforts to identify compact line_18: binaries in globular clusters, will provide a critical test of theories line_19: for the formation and evolution in clusters of interacting binaries and line_20: their progeny -- CVs, low-mass X-ray binaries, and millisecond pulsars. ! ! end of abstract general_form_proposers: lname: GRINDLAY fname: JONATHAN mi: E inst: 2170 country: USA ! lname: COOL fname: ADRIENNE mi: M. inst: 2170 country: USA ! lname: CALLANAN fname: PAUL mi: J. inst: 2170 country: USA ! lname: BAILYN fname: CHARLES mi: D. inst: 3900 country: USA ! lname: COHN fname: HALDAN mi: N. inst: 2270 country: USA ! lname: LUGGER fname: PHYLLIS mi: M. inst: 2270 country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: We propose to use the FOS with the red detector and G570H grating, line_2: covering the wavelength range 4571-6820 A. The target sequence is line_3: designed to provide reliable pointing at three science targets, which line_4: given their faintness and the extreme crowding in this globular line_5: cluster, cannot be acquired directly. The first target is a bright line_6: star which is sufficiently isolated that we can use the ACQ/BINARY line_7: target acquisition method. The remaining 6 targets consist of three line_8: pairs. The first star in each pair is a bright neighbor of a science line_9: target; the second star is the science target itself. We peak up line_10: (ACQ/PEAK) on the bright neighbor of each science target, then offset line_11: a small distance to the science target. The ACQ/PEAKs will be done line_12: using the 0.3" (0.26") aperture and .16-.18" steps to provide pointing line_13: to <= 0.13". We assume that the small offsets (1.3"--2.7") to the line_14: science targets will result in negligible additional uncertainty in line_15: the pointing. We use the 0.5" (0.43") aperture on all science targets, line_16: so that pointing uncertainties up to 0.2" can be tolerated. Given the line_17: anticipated 3 sigma uncertainty of 0.45" in the pointing following line_18: ACQ/BINARY, we use a 6x6 scan on the first "neighbor" star. For the line_19: other two "neighbor" stars we use 5x5 scans and 0.16" steps, as the line_20: uncertainty following the offsets to these stars should be less than line_21: 0.2". After each science target exposure, we take an "ACQ image" to line_22: provide a check on the pointing position. Coordinates have been line_23: measured by us and by the GASP group at STScI relative to the GSC. ! question: 4 section: 1 line_1: The extreme crowding in this globular cluster field requires the line_2: HST (see Question 3). ! question: 5 section: 1 line_1: The 11 "exposures" that make up this observation MUST BE DONE IN THE line_2: ORDER SPECIFIED (linenum 1 through linenum 11). This sequence (SEQ) is line_3: designed to obtain reliable and accurate pointing in this very crowded line_4: field at the center of a globular cluster (see Question 3). We give line_5: absolute positions of only the first target (measured for us at STScI line_6: relative to the GSC on PC frames we had previously obtained). It is line_7: the only target of the 7 that is sufficiently isolated to permit a line_8: reliable intial pointing. Once we have acquired this target we OFFSET line_9: to our other targets. See question 3 above for a detailed explanation line_10: of the observing strategy. ! question: 6 section: 1 line_1: ! ! question: 8 section: 1 line_1: ! question: 9 section: 1 line_1: We have successfully proposed for two photometry proposals and line_2: one archival research proposal for work related to this investigation: line_4: Cycle 1: Program P2555, ``Cataclysmic Variables and Millisecond Pulsars line_5: in Globular Cluster Cusps" (J. Grindlay, PI). line_6: Cycle 2: Program GO-3851, ``Deep Search for CVs and Compact Binaries line_7: in the Collapsed Close Globular NGC6397" (J. Grindlay, PI). line_8: Cycle 2, archival research: Program AR-3793, ``Comparison of HST Data line_9: on Globular Clusters with Other Data Sets" (C. Bailyn, PI). line_11: The P2555 program was for a preliminary H-alpha vs. R image of the line_12: core of NGC6752. A total of about 2 hours exposure was obtained with line_13: PC, yielding a senistivity limit of about Mv = 5. The data were line_14: incorrectly processed (at STScI) originally in that the wrong bias line_15: frames were used. The re-processed bias frames and flats were received line_16: only in January 1992, and we are currently still in the process of line_17: carrying out a DAOPHOT analsysis of the images. ! question: 10 section: 1 line_1: CfA is fully equipped to reduce HST data (with IRAF). Co-I's also have line_2: access to similar HST data reduction facilities. ! !end of general form text general_form_address: lname: GRINDLAY fname: JONATHAN mi: E category: PI inst: 2170 addr_1: HARVARD COLLEGE OBSERVATORY addr_2: CENTER FOR ASTROPHYSICS addr_3: MAIL STOP 6 city: CAMBRIDGE state: MA zip: 02138 country: USA phone: 617-495-7204 telex: 921428; INTERNET: JOSH@CFA255.HARVARD.EDU ! lname: category: CON ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: NGC6397-STAR1-OFFSET descr_1: A,138,C,201 pos_1: PLATE-ID=0688, pos_2: RA = 17H 40M 40.57S +/- 0.100S, pos_3: DEC = -53D 40' 01.1" +/- 1.00" equinox: J2000 pos_epoch_bj: J pos_epoch_yr: 2000.00 fluxnum_1: 1 fluxval_1: V = 14, B-V=0.85, TYPE=G5III fluxnum_2: 2 fluxval_2: E(B-V) = 0.2 ! targnum: 2 name_1: NGC6397-STAR2-OFFSET descr_1: A,138,C,201 pos_1: PLATE-ID=0688, pos_2: RA-OFF = 0.91S +/- 0.005S, pos_3: DEC-OFF = -20.0" +/- 0.05", pos_4: FROM 1 equinox: J2000 pos_epoch_bj: J pos_epoch_yr: 2000.00 fluxnum_1: 1 fluxval_1: V = 14, B-V=0.85, TYPE=G5III fluxnum_2: 2 fluxval_2: E(B-V) = 0.2 ! targnum: 3 name_1: NGC6397-STAR3 descr_1: A,161,C,201 pos_1: PLATE-ID=0688, pos_2: RA-OFF = 0.93S +/- 0.005S, pos_3: DEC-OFF = -18.8" +/- 0.05", pos_4: FROM 1 equinox: J2000 pos_epoch_bj: J pos_epoch_yr: 2000.00 fluxnum_1: 1 fluxval_1: V = 18 fluxnum_2: 2 fluxval_2: E(B-V) = 0.2 ! targnum: 4 name_1: NGC6397-STAR4-OFFSET descr_1: A,138,C,201 pos_1: PLATE-ID=0688, pos_2: RA-OFF = 1.81S +/- 0.005S, pos_3: DEC-OFF = -21.0" +/- 0.05", pos_4: FROM 1 equinox: J2000 pos_epoch_bj: J pos_epoch_yr: 2000.00 fluxnum_1: 1 fluxval_1: V = 15.8, B-V=0.7, TYPE=F8IV fluxnum_2: 2 fluxval_2: E(B-V) = 0.2 ! targnum: 5 name_1: NGC6397-STAR5 descr_1: A,161,C,201 pos_1: PLATE-ID=0688, pos_2: RA-OFF = 1.99S +/- 0.005S, pos_3: DEC-OFF = -18.7" +/- 0.05", pos_4: FROM 1 equinox: J2000 pos_epoch_bj: J pos_epoch_yr: 2000.00 fluxnum_1: 1 fluxval_1: V = 20 fluxnum_2: 2 fluxval_2: E(B-V) = 0.2 ! targnum: 6 name_1: NGC6397-STAR6-OFFSET descr_1: A,138,C,201 pos_1: PLATE-ID=0688, pos_2: RA-OFF = 1.67S +/- 0.005S, pos_3: DEC-OFF = -30.9" +/- 0.05", pos_4: FROM 1 equinox: J2000 pos_epoch_bj: J pos_epoch_yr: 2000.00 fluxnum_1: 1 fluxval_1: V = 14.4, B-V=0.18, TYPE=A0V fluxnum_2: 2 fluxval_2: E(B-V) = 0.18 ! targnum: 7 name_1: NGC6397-STAR7 descr_1: A,161,C,201 pos_1: PLATE-ID=0688, pos_2: RA-OFF = 1.64S +/- 0.005S, pos_3: DEC-OFF = -28.1" +/- 0.05", pos_4: FROM 1 equinox: J2000 pos_epoch_bj: J pos_epoch_yr: 2000.00 fluxnum_1: 1 fluxval_1: V = 18.8 fluxnum_2: 2 fluxval_2: E(B-V) = 0.2 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: NGC6397-STAR1-OFFSET config: FOS/RD opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 2.1S fluxnum_1: 1 priority: 1 req_1: CYCLE 4; req_2: ONBOARD ACQ FOR 2; req_3: SEQ 1-11 NO GAP ! linenum: 2.000 targname: NGC6397-STAR2-OFFSET config: FOS/RD opmode: ACQ/PEAK aperture: 0.3 sp_element: MIRROR num_exp: 1 time_per_exp: 2.0S fluxnum_1: 1 priority: 1 param_1: TYPE=UP param_2: SEARCH-SIZE-X=5 param_3: SEARCH-SIZE-Y=5 param_4: SCAN-STEP-X=0.18 param_5: SCAN-STEP-Y=0.18 req_1: CYCLE 4; req_2: ONBOARD ACQ FOR 3; ! linenum: 3.000 targname: NGC6397-STAR2-OFFSET config: FOS/RD opmode: ACCUM aperture: 0.5 sp_element: G570H wavelength: 4571-6815 num_exp: 1 time_per_exp: 60S fluxnum_1: 1 priority: 1 req_1: CYCLE 4; ! linenum: 4.000 targname: NGC6397-STAR3 config: FOS/RD opmode: ACCUM aperture: 0.5 sp_element: G570H wavelength: 4571-6815 num_exp: 1 time_per_exp: 25M fluxnum_1: 1 priority: 1 req_1: CYCLE 4; ! linenum: 5.000 targname: NGC6397-STAR3 config: FOS/RD opmode: ACQ aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 32S fluxnum_1: 1 priority: 1 req_1: CYCLE 4; ! linenum: 6.000 targname: NGC6397-STAR4-OFFSET config: FOS/RD opmode: ACQ/PEAK aperture: 0.3 sp_element: MIRROR num_exp: 1 time_per_exp: 7S fluxnum_1: 1 priority: 1 param_1: TYPE=UP param_2: SEARCH-SIZE-X=5 param_3: SEARCH-SIZE-Y=5 param_4: SCAN-STEP-X=0.16 param_5: SCAN-STEP-Y=0.16 req_1: CYCLE 4; req_2: ONBOARD ACQ FOR 7; ! linenum: 7.000 targname: NGC6397-STAR5 config: FOS/RD opmode: ACCUM aperture: 0.5 sp_element: G570H wavelength: 4571-6815 num_exp: 1 time_per_exp: 75M fluxnum_1: 1 priority: 1 req_1: CYCLE 4; ! linenum: 8.000 targname: NGC6397-STAR5 config: FOS/RD opmode: ACQ aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 6M fluxnum_1: 1 priority: 1 req_1: CYCLE 4; ! linenum: 9.000 targname: NGC6397-STAR6-OFFSET config: FOS/RD opmode: ACQ/PEAK aperture: 0.3 sp_element: MIRROR num_exp: 1 time_per_exp: 2S fluxnum_1: 1 priority: 1 param_1: TYPE=UP param_2: SEARCH-SIZE-X=5 param_3: SEARCH-SIZE-Y=5 param_4: SCAN-STEP-X=0.16 param_5: SCAN-STEP-Y=0.16 req_1: CYCLE 4; req_2: ONBOARD ACQ FOR 10; ! linenum: 10.000 targname: NGC6397-STAR7 config: FOS/RD opmode: ACCUM aperture: 0.5 sp_element: G570H wavelength: 4571-6815 num_exp: 1 time_per_exp: 28M fluxnum_1: 1 priority: 1 req_1: CYCLE 4; ! linenum: 11.000 targname: NGC6397-STAR7 config: FOS/RD opmode: ACQ aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 60S fluxnum_1: 1 priority: 1 req_1: CYCLE 4; ! ! end of exposure logsheet ! No scan data records found