! $Id: 5195,v 4.1 1994/07/27 15:51:59 pepsa Exp $ coverpage: title_1: EARLY RELEASE OBSERVATIONS OF A VIRGO SPIRAL sci_cat: GALAXIES & CLUSTERS sci_subcat: NEARBY GALAXIES proposal_for: SMC/ERO pi_title: DR. pi_fname: WILLIAM pi_lname: SPARKS pi_inst: STSCI pi_country: USA hours_pri: 3.52 num_pri: 1 wf_pc: Y ! end of coverpage abstract: line_1: A major goal of the Hubble Telescope is to resolve individual stars in line_2: galaxies in the Virgo Cluster. This information is critical to an line_3: improved extragalactic distance scale, and thus determination of the line_4: Hubble constant, as well as to an enhanced understanding of the structures line_5: and evolution of galaxies. We propose to demonstrate the recovery of line_6: this capability with WFPC2 by imaging M100 (NGC 4321), a grand design, line_7: two-arm spiral in the Virgo cluster. M100 not only will offer us a line_8: spectacular close-up of the resolved stellar components across the arms line_9: of a large spiral galaxy of the type used to find distances via the line_10: Tully-Fisher method, but also affords us a chance to probe the poorly ! ! end of abstract general_form_proposers: lname: SPARKS fname: WILLIAM title: DR. inst: STSCI country: USA esa: N ! lname: GALLAGHER fname: JAY title: DR. mi: S. inst: 3884 country: USA esa: N ! lname: BAUM fname: WILLIAM title: DR. mi: A. inst: 3760 country: USA esa: N ! lname: MOULD fname: JEREMY title: DR. mi: R. inst: 1590 country: USA esa: N ! lname: FABER fname: SANDRA title: DR. mi: M. inst: 1552 country: USA esa: N ! lname: HUNTER fname: DEIDRE title: DR. mi: A. inst: 2540 country: USA esa: N ! lname: LIGHT fname: ROBERT title: DR. mi: M. inst: 1590 country: USA esa: N ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: A major goal of the Hubble Telescope is to resolve individual stars in line_2: galaxies in the Virgo Cluster. This information is critical to an line_3: improved extragalactic distance scale, and thus determination of the line_4: Hubble constant, as well as to an enhanced understanding of the structures line_5: and evolution of galaxies. We propose to demonstrate the recovery of line_6: this capability with WFPC2 by imaging M100 (NGC 4321), a grand design, line_7: two-arm spiral in the Virgo cluster. M100 not only will offer us a line_8: spectacular close-up of the resolved stellar components across the arms line_9: of a large spiral galaxy of the type used to find distances via the line_10: Tully-Fisher method, but also affords us a chance to probe the poorly line_11: understood environment around an actively star-forming galactic nucleus. ! question: 2 section: 2 line_1: Images of M100 should be obtained in three filters with moderately long line_2: exposures to allow us to construct a color image of the galaxy. In line_3: the post-refurbishment observations, the pointing line_4: can be chosen such that the PC chip observes the nuclear region, while the WF line_5: chips fall along inner and outer spiral arms. We can then demonstrate how the line_6: configuration of WFPC2 can be effectively applied to extragalactic targets. line_7: Results of a three filter exposure can be expected to include measurements of line_8: luminous stellar populations across spiral arms where individual stars will be line_9: resolved, observations of interstellar matter as dark clouds, especially in line_10: the inner regions of the galaxy, a census of star clusters, and a first look at line_11: the distributions of stars and gas (via dust lanes) near the nucleus. ! question: 2 section: 3 line_1: Excellent ground-based data are available for this galaxy; e.g. see the Sandage line_2: and Bedke Atlas for a continuum photograph. In addition Gallagher has narrow line_3: band images in the Halpha line taken under good seeing conditions, which show a line_4: the bright nucleus is surrounded by four arms which extend to a ring that line_5: divides the nuclear zone from the main spiral features. ! question: 3 section: 1 line_1: Short description of proposed observations line_3: We propose to obtain BV and R images, both very short images taken to explore line_4: the nuclear regions and assess the brightness levels there, and also lengthier line_5: exposures of order one orbit per filter which, post-refurbishment, should be line_6: adequate to detect Cepheids at the distance of Virgo. ! question: 4 section: 1 line_1: (a) Justify the need for the capabilities if HST. line_3: To measure Cepheid variables at the Virgo cluster requires sensitivity line_4: and resolution that only HST has. line_7: (b) Justify the amount of exposure time. line_10: We propose to obtain BV and R images, both very short images taken to explore line_11: the nuclear regions, and also lengthier line_12: exposures of order one orbit per filter which should be line_13: adequate to detect Cepheids at the distance of Virgo. ! question: 5 section: 1 line_1: ! question: 6 section: 1 line_1: Special calibrations line_3: None ! question: 7 section: 1 line_1: Data reduction and analysis line_3: The data will be rapidly processed for early assessment of the HST recovery. ! !end of general form text general_form_address: lname: Sparks fname: William title: Dr. category: PI inst: STScI addr_1: 3700 San Martin city: BALTIMORE state: MD zip: 21218 country: USA phone: 410-338-4827 telex: 410-338-1592 from_date: 21-MAR-88 to_date: 21-MAR-98 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: NGC4321 name_2: M100 descr_1: E,301 pos_1: RA=12H 20M 23S +/- 0.5S, pos_2: DEC=+16D 6' 0" +/- 1.0" equinox: 1950 fluxnum_1: 1 fluxval_1: B=10.0 fluxnum_2: 2 fluxval_2: B-V=0.5 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: SPIM targname: NGC4321 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: # num_exp: 2 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: CR-SPLIT=NO, req_1: CYCLE 4; ! linenum: 10.000 sequence_1: USE sequence_2: SPIM sp_element: F555W time_per_exp: X10 ! linenum: 11.000 sequence_1: USE sequence_2: SPIM sp_element: F439W time_per_exp: X60 ! linenum: 12.000 sequence_1: USE sequence_2: SPIM sp_element: F702W time_per_exp: X5 ! linenum: 20.000 sequence_1: USE sequence_2: SPIM sp_element: F555W time_per_exp: X900 ! linenum: 21.000 sequence_1: USE sequence_2: SPIM sp_element: F439W time_per_exp: X900 ! linenum: 22.000 sequence_1: USE sequence_2: SPIM sp_element: F702W time_per_exp: X600 ! linenum: 23.000 sequence_1: USE sequence_2: SPIM sp_element: F702W time_per_exp: X600 ! ! end of exposure logsheet ! No scan data records found