!   $Id: 5386,v 4.1 1994/07/27 17:23:19 pepsa Exp $

coverpage:

  title_1:         STELLAR POPULATIONS OF THE LEO II DWARF SPHEROIDAL GALAXY
    sci_cat:       COOL STARS
    sci_subcat:    STELLAR POPULATIONS
    proposal_for:  GO
    pi_fname:      KENNETH
    pi_mi:         J
    pi_lname:      MIGHELL
    pi_inst:       COLUMBIA UNIVERSITY
    pi_country:    USA
    pi_phone:      212-854-6899
    hours_pri:     4.08
    num_pri:       1
    wf_pc:         Y
    off_fname:     BETH
    off_lname:     ISRAEL
    off_title:     ASSOC. DIRECTOR
    off_inst:      1770
    off_addr_1:    OFFICE OF PROJECTS AND GRANTS
    off_addr_2:    405 LOW MEMORIAL LIBRARY
    off_addr_3:    COLUMBIA UNIVERSITY
    off_city:      NEW YORK
    off_state:     NY
    off_zip:       10027
    off_country:   USA
    off_phone:     212-854-6851
! end of coverpage

abstract:

    line_1:        We propose to obtain deep V and I photometry of the Leo II dwarf spheroidal
    line_2:        galaxy using the WFPC2 and the F555W and F791 filters.  We will produce a deep
    line_3:        HR diagram of this Local Group galaxy which will be analyzed to determine its
    line_4:        age and star formation history.  This galaxy has luminous carbon stars and an
    line_5:        anomalously red horizontal branch which indicates the presence of at least some
    line_6:        intermediate age stars, and suggests that Leo II is younger than the Draco and
    line_7:        Ursa Minor dwarf spheroidals.

!
! end of abstract

general_form_proposers:

  lname:           MIGHELL
    fname:         KENNETH
    mi:            J
    inst:          1770
    country:       USA

!

  lname:           RICH
    fname:         R. MICHAEL
    inst:          1770
    country:       USA

!
! end of general_form_proposers block

general_form_text:

  question:        3
    section:       1
    line_1:        Leo II has a distance modulus (m-M)=21.85 (Demers & Harris 1983).  An
    line_2:        intermediate-age turnoff would occur at V=25; an old trunoff at V=26.
    line_3:        We seek (V-I) color errors less than 0.30 mag for a F0 star at V=27.
    line_4:        A 4800 second exposure in F555W gives S/N=7.9 and a 4800 second exposure
    line_5:        in F791W gives S/N=5.1.  The combined color error is 0.28 mag.
    line_7:        Filter: F555W has QT_integral = 0.0250
    line_8:        Star: V=27, F0 star has AB_V=0.030 (average of 500 and 600 nm)
    line_9:        Stellar flux: I=(2.5E+11)*(QT_integral)*10**(-0.4(V+AB_V))=0.096 e/sec
    line_10:       Sky: WF -> V=27.1 (Leo II is near the ecliptic), AB_V = 0.035
    line_11:       Sky flux: B=(2.5E+11)*(QT_integral)*10**(-0.4(V+AB_V))=0.087 e/sec
    line_12:       Total Exposure: T=4800 sec
    line_13:       S/N correction: C=0.261 (WF Center & Corner, avgerage of 400 and 800 nm)
    line_14:       S/N=I*SQRT((T*C)/(B+I))= 7.9 in 4800 sec
    line_16:       Filter: F791W has QT_integral = 0.0169
    line_17:       Star: V=27, F0 star has AB_V=0.080 (800 nm)
    line_18:       Stellar flux: I=(2.5E+11)*(QT_integral)*10**(-0.4(V+AB_V))=0.062 e/sec
    line_19:       Sky: WF -> V=27.1 (Leo II is near the ecliptic), AB_V = -0.55
    line_20:       Sky flux: B=(2.5E+11)*(QT_integral)*10**(-0.4(V+AB_V))=0.101 e/sec
    line_21:       Total Exposure: T=4800 sec
    line_22:       S/N correction: C=0.226 (WF Center & Corner, 800 nm)
    line_23:       S/N=I*SQRT((T*C)/(B+I))= 5.1 in 4800 sec

!

  question:        3
    section:       2
    line_1:
    line_2:        We will take 2x80 sec exposures with ATD-GAIN=15 and 4x1200 sec exposures with
    line_4:        ATD-GAIN=7 for both filters (F555W and F791W).  The short high-gain exposures
    line_5:        increase the dynamic range of the long low-gain exposures.
    line_7:        We would like all the exposures to be taken together as one group with only
    line_8:        interruptions due to Earth occultations (GROUP 1-4 NO GAP).  We would like
    line_9:        all exposures to be made at the same position in the sky with the same
    line_10:       telescope roll angle (SAME POS FOR 2-4 AS 1).  Each 1200 second exposure will
    line_11:       be split in half (CR-SPLIT=0.5) to minimize cosmic-ray contamination.

!

  question:        4
    section:       1
    line_1:        See answer to question 4.a. on the HST Cycle 4 proposal general form.

!

  question:        5
    section:       1
    line_1:

!

  question:        6
    section:       1
    line_1:

!


!

  question:        8
    section:       1
    line_1:

!

  question:        9
    section:       1
    line_1:        See answer to question 9. on the HST Cycle 4 proposal general form.

!

  question:        10
    section:       1
    line_1:        See answer to question 10. on the HST Cycle 4 proposal general form.

!
!end of general form text

general_form_address:

  lname:           MIGHELL
    fname:         KENNETH
    mi:            J
    category:      PI
    inst:          1770
    addr_1:        DEPT. OF ASTRONOMY
    addr_2:        COLUMBIA UNIVERSITY
    addr_3:        538 WEST 120TH STREET
    city:          NEW YORK
    state:         NY
    zip:           10027
    country:       USA
    phone:         212-854-6899
    telex:         MIGHELL@FIGARO.PHYS.COLUMBIA.EDU

!
! end of general_form_address records

fixed_targets:

    targnum:       1
    name_1:        LEO-II
    descr_1:       E, 308
    pos_1:         RA = 11H 13M 32.00S +/- 0.10S,
    pos_2:         DEC = +22D 09' 30" +/- 0.10"
    equinox:       2000.0
    comment_1:     POSITION CHOSEN TO AVOID BRIGHT
    comment_2:     STAR NEAR THE CENTER OF THE GALAXY
    fluxnum_1:     1
    fluxval_1:     V=12.4
    fluxnum_2:     2
    fluxval_2:     B-V=1.0

!
! end of fixed targets

! No solar system records found

! No generic target records found

exposure_logsheet:

    linenum:       1.000
    targname:      LEO-II
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1
    sp_element:    F555W
    num_exp:       2
    time_per_exp:  80S
    s_to_n:        7.9
    s_to_n_time:   4800S
    fluxnum_1:     1
    priority:      1
    param_1:       ATD-GAIN=15, CR-SPLIT=NO
    req_1:         CYCLE 4; PCS MODE F;

!

    linenum:       2.000
    targname:      LEO-II
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1
    sp_element:    F555W
    num_exp:       4
    time_per_exp:  1200S
    s_to_n:        7.9
    s_to_n_time:   1200S
    fluxnum_1:     1
    priority:      1
    param_1:       ATD-GAIN=7,
    param_2:       CR-SPLIT=0.5,
    param_3:       CR-TOLERANCE=0.0
    req_1:         CYCLE 4; PCS MODE F;

!

    linenum:       3.000
    targname:      LEO-II
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1
    sp_element:    F814W
    num_exp:       2
    time_per_exp:  80S
    s_to_n:        5.1
    s_to_n_time:   4800S
    fluxnum_1:     1
    priority:      1
    param_1:       ATD-GAIN=15,
    param_2:       CR-SPLIT=NO,
    req_1:         CYCLE 4; PCS MODE F;

!

    linenum:       4.000
    targname:      LEO-II
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1
    sp_element:    F814W
    num_exp:       4
    time_per_exp:  1200S
    s_to_n:        5.1
    s_to_n_time:   4800S
    fluxnum_1:     1
    priority:      1
    param_1:       ATD-GAIN=7,
    param_2:       CR-SPLIT=0.5,
    param_3:       CR-TOLERANCE=0.0
    req_1:         CYCLE 4; PCS MODE F;
    req_2:         GROUP 1-4 NO GAP;
    req_3:         SAME POS FOR 2-4 AS 1;

!
! end of exposure logsheet

! No scan data records found