! $Id: 5423,v 7.1 1994/07/27 17:47:11 pepsa Exp $ coverpage: title_1: THE TUCANA DWARF SPHEROIDAL GALAXY sci_cat: GALAXIES & CLUSTERS sci_subcat: STELLAR POPULATIONS proposal_for: GO pi_fname: PATRICK pi_mi: O. pi_lname: SEITZER pi_inst: 2660 pi_country: USA pi_phone: 313-936-1741 hours_pri: 11.80 num_pri: 1 wf_pc: Y ! end of coverpage abstract: line_1: WFPC2 images of the core of the recently discovered Tucana dwarf line_2: spheroidal galaxy will be used to construct a color magnitude line_3: diagram that shows for the first time the horizontal branch line_4: magnitude and morphology of this system. An accurate distance line_5: modulus of this isolated Local Group member will be determined line_6: as well. All other galaxies of this class are line_7: satellites of much larger parent galaxies, such as the eight line_8: known systems around our Galaxy and the three systems around line_9: M31. In addition, the internal abundance dispersion of line_10: Tucana can be determined from the width of the giant branch line_11: at a faint enough level to be free from AGB star line_12: contamination. We will compare these characteristics with line_13: those of other known dwarf spheroidal galaxies, and line_14: determine what is unique about this isolated Local Group system. ! ! end of abstract general_form_proposers: lname: SEITZER fname: PATRICK mi: O. inst: 2660 country: USA ! lname: LAVERY fname: RUSSELL inst: 1662 country: USA ! lname: WALKER fname: ALISTAIR inst: 4720 country: USA ! lname: SUNTZEFF fname: NICHOLAS inst: 4720 country: USA ! lname: DA COSTA fname: GARY inst: ANGLO-AUSTRALIAN OBSERVATORY country: AUSTRALIA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: First, for each filter (F555W and F814W) we will first line_2: do a series of short exposures line_3: for comparison with groundbased calibration and photometry line_4: of the brighter stars. line_5: Next, we will do a series of long 1800 second exposures line_6: offsetting between them to provide a check on photometric line_7: errors. line_8: We prefer that the entire sequence be taken at the same pointing line_9: to ensure that the short and long exposures in both filters line_10: have the stars in the same place on the PC. line_11: Hence, we have specified SEQ NO GAP ! question: 4 section: 1 line_1: Both the CTIO and AAO 4 meter reflectors (the largest telescopes in the line_2: southern hemisphere) equipped with CCD cameras have been used to line_3: observe Tucana. In several observing seasons we have reached the limit line_4: of groundbased studies of this system. Accurate photometry at the line_5: expected V magnitude of the horizontal branch (V = 25.3) is line_6: considerably beyond the capability of these telescopes even in the best line_7: seeing. The problem is not only the faintness of the stars we are line_8: interested in, but also the crowding and confusion. Even in sub arc line_9: second seeing the images of stars at V=25.3 will be blended with line_10: brighter stars. The full resolution of the PC is required to obtain line_11: the accurate photometry necessary to address the problems set forth line_12: here. ! question: 5 section: 1 line_1: None. ! question: 6 section: 1 line_1: None. ! ! question: 8 section: 1 line_1: ! question: 9 section: 1 line_1: Seitzer and Da Costa are both Co-Is in GO proposal 2419 "The Chronology line_2: of the Formation of the Galatic Halo and Disk". Zinn is PI of that line_3: proposal and the Co-Is are Carney, Christian, Da Costa, Demarque, line_4: Heasley, Janes, Olszewski and Seitzer. It is not directly line_5: scientifically related to the present proposal. This is a Cycle 1 line_6: proposal. ! question: 10 section: 1 line_1: Computing resources will be made available at all of our institutions line_2: (Michigan, DTM, CTIO, and the AAO) for the reduction of this data. line_3: Should additional ground based data be required, the University line_4: of Michigan will provide telescope time on its Curtis Schmidt telescope line_5: at CTIO, and access to larger instruments at CTIO and the AAO will be line_6: sought through normal TAC procedures. ! !end of general form text general_form_address: lname: Seitzer fname: Patrick category: PI inst: 2660 addr_1: Dept. of Astronomy addr_2: University of Michigan addr_3: 830 Dennison Building city: Ann Arbor state: MI zip: 48109 country: USA phone: 313-936-1741 telex: seitzer@astro.lsa.umich.edu ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: TUCANA name_2: 049V descr_1: E,308 pos_1: PLATE-ID=049V, pos_2: RA = 22H 41M 48.030S +/- 0.2S, pos_3: DEC = -64D 25' 16.22" +/- 0.5" equinox: 2000.0 fluxnum_1: 1 fluxval_1: SURF(V) = 24.5 +/- 1.0 fluxnum_2: 2 fluxval_2: B-V = 0.8 +/- 0.2 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: TUCANA config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F555W num_exp: 3 time_per_exp: 180.00S s_to_n: 3 s_to_n_time: 180.00S fluxnum_1: 1,2 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4/1-4; req_2: GROUP 1-4 NO GAP; req_3: POS TARG 0.0,0.0; req_4: SAME POS FOR 2-4 AS 1 ! linenum: 2.000 targname: TUCANA config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F555W num_exp: 4 time_per_exp: 1800.00S s_to_n: 10 s_to_n_time: 1800.00S fluxnum_1: 1,2 priority: 1 param_1: CR-SPLIT=NO ! linenum: 3.000 targname: TUCANA config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F814W num_exp: 3 time_per_exp: 180.00S s_to_n: 3 s_to_n_time: 180.00S fluxnum_1: 1,2 priority: 1 param_1: CR-SPLIT=NO ! linenum: 4.000 targname: TUCANA config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F814W num_exp: 7 time_per_exp: 1800.00S s_to_n: 10 s_to_n_time: 1800.00S fluxnum_1: 1,2 priority: 1 param_1: CR-SPLIT=NO ! linenum: 12.000 targname: TUCANA config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F555W num_exp: 4 time_per_exp: 1800.00S s_to_n: 10 s_to_n_time: 1800.00S fluxnum_1: 1,2 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4/12-13; req_2: GROUP 12-13 NO GAP; req_3: POS TARG 0.86, 0.86; req_4: SAME POS FOR 13 AS 12 ! linenum: 13.000 targname: TUCANA config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F814W num_exp: 8 time_per_exp: 1800.00S s_to_n: 10 s_to_n_time: 1800.00S fluxnum_1: 1,2 priority: 1 param_1: CR-SPLIT=NO ! ! end of exposure logsheet ! No scan data records found