! File: 4324C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:21:53:11 coverpage: title_1: SEARCH FOR THE REAL OPTICAL COUNTERPART OF 4U1543-47 title_2: CYC3SUPPLEMENTAL sci_cat: HOT STARS sci_subcat: X-RAY BINARIES proposal_for: GO pi_fname: SERGIO pi_mi: A. pi_lname: ILOVAISKY pi_inst: OBSERVATOIRE DE HAUTE PROVENCE pi_country: FRANCE hours_pri: 0.78 num_pri: 1 wf_pc: Y off_fname: PHILIPPE off_lname: VERON off_title: DIRECTOR off_inst: 5456 off_addr_1: 04870 ST.MICHEL L'OBSERVATOIRE off_country: FRANCE off_phone: (33)92706400 ! end of coverpage abstract: line_1: The identification of the optical counterpart of the 4U1543-47 line_2: soft X-ray transient is a puzzle. Ground-based observations made in line_3: 1983 during an active state resulted in the identification of a line_4: counterpart which displayed a typical low-mass X-ray binary spectrum line_5: but had changed in brightness by only 1 magnitude compared to archival line_6: Schmidt plates (normally such transients display amplitudes of 6 line_7: magnitudes or more). Further ground-based observations in 1989 line_8: revealed that during quiescence the visible object is a normal V=16.7 line_9: A-type star. Both the active and quiescent images coincide to +/- 0.1 line_10: arcsec. While it is unlikely that the A-star is the binary companion line_11: to the X-ray source, it appears nevertheless to be at the same line_12: distance from us. 4U1543-47 turned on again in April 1992 and we line_13: obtained director's discretionary time to make PC images of the field line_14: during outburst. They were obtained on 23 July. We propose to obtain line_15: PC images during quiescence in 1993 and compare them with those line_16: taken in July 1992 to identify the counterpart. ! ! end of abstract general_form_proposers: lname: ILOVAISKY fname: SERGIO title: PI mi: A. inst: OBSERVATOIRE DE HAUTE PROVENCE country: FRANCE esa: Y ! lname: CHEVALIER fname: CLAUDE inst: OBSERVATOIRE DE HAUTE PROVENCE country: FRANCE esa: Y ! lname: PEDERSEN fname: HOLGER inst: COPENHAGEN UNIVERSITY OBSERVATORY country: DENMARK esa: Y ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: 4U1543-47 is an X-ray transient which has been observed in line_2: outburst in 1971 and 1983. In late April 1992 it went into line_3: outburst again (Harmon et al. 1992). From its ultra-soft line_4: X-ray spectrum it is considered a black hole candidate, line_5: similar to A0620-00 and GS2000+25. During the 1983 outburst line_6: EXOSAT observed the source (Blisset 1983, van der Woerd et line_7: al. 1989) and it was subsequently identified by Pedersen et line_8: al. (1983) with a V=14.6 object displaying the line_9: characteristic emission lines of low-mass X-ray binaries. line_10: However, comparison with ESO Schmidt plates taken during line_11: quiescence showed that the object had brightened by only 1 line_12: magnitude. This was surprising for such a type of transient line_13: where optical amplitudes of 6 magnitudes or more are common. ! question: 2 section: 2 line_1: Optical observations made by us at ESO during quiescence in line_2: 1989 (Chevalier 1989) reveal that the V=16.7 star appearing line_3: at the location of the outburst image is a normal-looking line_4: A-type star. Spectra show interstellar features remarkably line_5: similar to those seen in the outburst spectrum, suggesting line_6: that both the A-star and the X-ray source are located at line_7: 4kpc. Astrometry made by comparing the 1983 and 1989 CCD line_8: frames, both taken at the 1.54m Danish telescope, shows that line_9: the two stellar images coincide to within 0.2 pixel (0.1 line_10: arc-sec). The outburst spectra also show shallow Balmer line_11: absorption lines which are obviously due to the A star. What line_12: is the counterpart of the X-ray source ? Is the A star an line_13: interloper in the line of sight or a third member in the line_14: binary system ? If the A star is not in the line of sight to line_15: the source, we can detect the true optical counterpart with line_16: higher angular resolution (HST) observations. ! question: 2 section: 3 line_1: Director's Discretionary time was obtained to get PC images line_2: of the field at the end of the 1992 outburst. Comparison of line_3: these data, taken in July, with data we propose to take line_4: during quiescence should allow the identification of the line_5: true optical counterpart of 4U1543-47. If the A-star still line_6: appears to be the only viable counterpart, this means that line_7: it probably is a third body in a hierarchical triple binary line_8: system. This would be a important result as no such systems line_9: are known, although their existence has been postulated line_10: before, as in the case of 4U2129+47 (Chevalier et al. 1989). ! question: 2 section: 4 line_1: Chevalier, C. (1989) ESA SP-296 p.341 line_2: Chevalier et al. (1989) Astr.Ap. 217,108 line_3: Pedersen, H. et al. (1983) IAUC 3858 line_4: van der Woerd et al. (1989) Ap.J. 344,320 line_5: Della Valle et al. (1992) IAUC 5512 line_6: Harmon et al. (1992) IAUC 5504 line_7: Blissett (1983) IAUC 3858 ! question: 3 section: 1 line_1: PC images of the 4U1543-47 field were taken in July 1992 line_2: through two different filters: F555W to compare with line_3: ground-based observations and F336W to maximize the line_4: contribution from the X-ray source while minimizing the line_5: influence of the A-star and of the bright V=11.7 star a few line_6: arc-seconds away. Two exposures of different duration were line_7: taken per filter to insure detection of the counterpart in line_8: case it had decreased in brightness (Maximum emission was on line_9: April 20). ! question: 3 section: 2 line_1: We now propose to obtain WF/PC images of the same field line_2: during the quiescent state of the source in 1993 through the line_3: same filters. Comparison of the images taken during the late line_4: stages of the outburst decay with the images to be obtained line_5: during quiescence could reveal the true optical counterpart. line_6: The counterpart should have decreased in brightness and line_7: changed color, as the contribution from the accretion disk line_8: decreases. If no such counterpart is detected, the A-star line_9: may then be related to the X-ray system. ! question: 4 section: 1 line_1: Existing ground-based observations do not allow us to answer line_2: the question of whether the A-star is associated to the line_3: X-ray source or not. The images of the source in outburst line_4: and in quiescence coincide to within +/- 0.1 arcsec. Only line_5: much higher resolving power observations with the WF/PC line_6: during the current outburst and in quiescence will allow a line_7: direct attack on this problem. ! question: 4 section: 2 line_1: We request an approximate repeat of our exposures carried line_2: out in July 23. They were taken using two filters (F336W and line_3: F555W) to obtain crude spectral information on the objects line_4: detected. As the object will now have returned to its line_5: quiescent state, 1.8 magnitudes fainter, the new images line_6: should have exposure times five times longer in order to line_7: reach the same S/N ratio as in July 1992 when the object was line_8: brighter. The comparison of these new images with the older line_9: ones should reveal whether any change in position of the line_10: object has taken place. We also request a deeper exposure in line_11: F555W in order to detect any near-by objects which would not line_12: have been detected in the shorter exposures. We request line_13: exposures of 50sec, 200sec and 800sec with F555W and 2 line_14: exposures of 800sec with F336W. The total exposure time and line_15: the number of exposures are less than or equal to what was line_16: approved in Phase I. ! question: 5 section: 1 line_1: None. ! question: 6 section: 1 line_1: None. ! question: 7 section: 1 line_1: The PC images of the 4U1543-47 field will be analyzed in line_2: order to derive positions and magnitudes for all objects line_3: detected. This will make use of the DAOPHOT photometric line_4: package, as available in MIDAS. If an object appears to have line_5: changed in brightness and/or color, it will be selected for line_6: further analysis in Cycle 4. ! question: 8 section: 1 line_1: None. ! question: 9 section: 1 line_1: Program ID 4165 - GO/DD line_2: "Astrometry of the 4U1543-47 X-ray transient optical counterpart" ! question: 9 section: 2 line_1: The data have been analyzed and reveal that the transient line_2: was still bright in July 1992, consistent with our 1983 line_3: ground-based observations made during the last active state. line_4: Comparison of the stellar image of the counterpart with PSFs line_5: computed using TinyTIM show the object is single. Thus a line_6: definitive answer can only come if we compare the active line_7: state July 1992 images with images obtained in quiescence. ! question: 9 section: 3 line_1: None (complete data set not yet available). ! question: 10 section: 1 line_1: Data analysis will make use of the VAX/VMS cluster at line_2: Haute-Provence Observatory, which includes a microVAX 3400, line_3: a VAXstation 3100 and two VAXstation 4000 VLC. Available line_4: astronomical software packages are MIDAS, Iraf and STSDAS. ! !end of general form text general_form_address: lname: ILOVAISKY fname: SERGIO mi: A. category: PI inst: Observatoire de Haute Provence addr_1: 04870 ST.MICHEL L'OBSERVATOIRE country: FRANCE phone: (33)92706465 telex: 410690F ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: 4U1543-47 descr_1: (A;164) pos_1: RA = 15H 43M 33.72S +/- 0.05S, pos_2: DEC = -47D 30' 56.6" +/- 0.5" equinox: 1950 acqpr_1: COMP comment_1: BRIGHT STAR (V=11.7) 5"7 WEST comment_2: AND 2"3 NORTH FROM TARGET fluxnum_1: 1 fluxval_1: V=16.7 fluxnum_2: 2 fluxval_2: B=17.5 fluxnum_3: 3 fluxval_3: E(B-V)=0.7 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: 4U1543-47 config: PC opmode: IMAGE aperture: P6 sp_element: F336W num_exp: 4 time_per_exp: 400S s_to_n: 100 fluxnum_1: 1 priority: 1 param_1: PRE-FLASH=YES req_1: CYCLE 3; req_2: ORIENT 22D +/- 70D / 1.000-4.000; req_3: SAME ORIENT FOR 2.000-4.000 AS 1.000 comment_1: ORIENT 22D +/- 70D / 1.000-4.000 comment_2: ALSO ACCEPTABLE ! linenum: 2.000 targname: 4U1543-47 config: PC opmode: IMAGE aperture: P6 sp_element: F555W num_exp: 1 time_per_exp: 50S s_to_n: 100 fluxnum_1: 1 priority: 1 param_1: PRE-FLASH=YES req_1: CYCLE 3 ! linenum: 3.000 targname: 4U1543-47 config: PC opmode: IMAGE aperture: P6 sp_element: F555W num_exp: 1 time_per_exp: 200S s_to_n: 100 fluxnum_1: 1 priority: 1 param_1: PRE-FLASH=YES req_1: CYCLE 3 ! linenum: 4.000 targname: 4U1543-47 config: PC opmode: IMAGE aperture: P6 sp_element: F555W num_exp: 2 time_per_exp: 400S s_to_n: 100 fluxnum_1: 1 priority: 1 param_1: PRE-FLASH=YES req_1: CYCLE 3 ! ! end of exposure logsheet ! No scan data records found