! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template
! $Id: 6352,v 6.1 1995/12/22 23:59:58 pepsa Exp $
! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template
! $Id: 6352,v 6.1 1995/12/22 23:59:58 pepsa Exp $
!
! Refer to the HST Phase II Proposal Instructions to fill this out
!
! Anything after a "!" is ignored, and may be deleted
!
! All keywords with multiple entries are comma delimited except the
! Visit_Requirements and Special_Requirements keywords which can be
! delimited with carriage returns or semi-colons, but not commas
!
! For help call your Program Coordinator: van Orsow
! Phone: 410-338-4568 , E-mail: vanorsow@stsci.edu
!
! This partially completed template was generated from a Phase I proposal.
! Name of Phase I Proposal: archive-0921.ferguson.prop
! Date generated: Fri Dec 22 18:59:36 EST 1995
!
Proposal_Information ! Section 4
Title: Dwarf Elliptical Galaxy Snapshot Survey
Proposal_Category: SNAP
Scientific_Category: STELLAR POPULATIONS
Cycle: 6
Investigators
PI_name: Henry Ferguson
PI_Institution: Space Telescope Science Institute
CoI_Name: Bryan Miller
CoI_Institution: Space Telescope Science Institute
Contact: ! Y or N (designate at most one contact)
CoI_Name: Brad Whitmore
CoI_Institution: Space Telescope Science Institute
Contact: ! Y or N (designate at most one contact)
CoI_Name: Massimo Stiavelli
CoI_Institution: Space Telescope Science Institute
Contact: ! Y or N (designate at most one contact)
Abstract: ! Free format text (please update)
Snapshot images in V and I will be obtained for 30 dwarf
elliptical galaxies. This survey will provide important
information on the globular cluster systems of such galaxies
and the properties of their cores and nuclei. The data will
provide a straightforward indication of whether dE's are true
low-luminosity ellipticals, or simply dwarf irregulars that
have lost their gas. The images will be searched for evidence
that the nuclei formed recently, and for the existence of dust
or low levels of star formation in the more extended dE
envelopes. Comparison of this data set to HST images of
luminous elliptical galaxies and their globular cluster
systems should provide valuable clues to the formation of
galaxies and their globular cluster systems. The data will be
non-proprietary.
Questions ! Free format text (please update)
Observing_Description:
We propose a snapshot survey of 30 galaxies from a dE sample
of roughly 1000. As the database will be of immediate use in
a variety of comparative studies to other HST data, we will
waive our proprietary rights. Our optimum exposure sequence
is two exposures of 230 sec each in F555W, and one exposure
of 350 seconds in F814W. The total time per target will be 29
minutes including guide-star acquisition and instrument
overheads. Fine lock is required for guiding. Shorter
exposure times can be used for smaller observing windows;
however windows shorter than 20 minutes are not useful due to
our requirement for fine lock and good cosmic ray removal. As
a primary goal is a first statistical assessment of the
globular cluster dE population, we have chosen a large sample
of potential targets and modest exposure times per galaxy.
For a distance modulus of 31.7 (the largest of the dwarfs in
our sample, for H_0 = 75 km s^-1 Mpc^-1), exposure times to
reach S/N = 10 at the peak of the luminosity function (M_V =
-7) are 300 sec in F814W. This program is thus ideal for a
snapshot survey. The major sources of background in order of
importance are (1) cosmic rays, (2) background galaxies, and
(3) the dE galaxy itself. With three short exposures, even in
different bands, we expect virtually no contamination from
cosmic rays. Background galaxies are a much more important
source of false detections. Typical effective radii of the
dE galaxies in our sample are 15". At V=25, there are
roughly 7 * 10^4 galaxies per square degree. Thus, within
15", we expect 4 background galaxies. At this magnitude
faint galaxies are still in general well resolved by HST,
with median half-light radii of 0.15 arcsec (Griffiths et
al. 1994). In contrast, globular clusters at the Virgo
Cluster distance are barely resolved, with r_e ~ 0.04"
(Whitmore et al. 1995). Thus most background galaxies can be
identified by morphology, as has proved to be the case with
existing data. Colors will provide additional discrimination,
but the median colors of galaxies at I ~ 25 is similar to
that of globular clusters, so this must be used with care. If
necessary, statistical corrections can be made to the
measured values of S_N based on the number of globular-
cluster like objects seen in archival blank-field
observations. These corrections will dominate the
uncertainties for galaxies fainter than M_B = -15 if <S_N> is
less than 1. However, we do not wish to bias our sample by
selecting only high-luminosity dE's, as that presupposes that
<S_N> is independent of luminosity. We note that a globular
cluster population the size of that in the Fornax dSph would
be detectable at the 2-sigma level with only a statistical
correction for background galaxies. The smooth background of
the dE galaxy itself increases the exposure time to detect an
unresolved source. For galaxies fainter than M_V = -14.5 even
the central surface brightnesses are fainter than the sky
background, so globular clusters can be detected all the way
in to the center. For galaxies at the bright end of our
sample (M_V = -17), central surface brightnesses are still
considerably fainter than in the central regions of M87
surveyed by Whitmore et al. (1995). The expected globular
cluster populations are high enough at M_B = -17 that the
loss of the central few arcseconds will not significantly
affect the determination of S_N.
Real_Time_Justification:
None.
None.
Calibration_Justification: ! Move appropriate text from Real_Time_Justification
Additional_Comments:
Fixed_Targets ! Section 5.1
Target_Number:
Target_Name:
Alternate_Names:
Description:
Position: ! Most common specification format is
! RA=0H 0M 0.00S +/- 0S,
! DEC=0D 0' 0.0" +/- 0",
! PLATE-ID=0000
Equinox:
RV_or_Z:
RA_PM: ! Units are seconds of time per year
Dec_PM: ! Units are seconds of arc per year
Epoch:
Annual_Parallax:
Flux: ! Include at least V and B-V
Comments:
Solar_System_Targets ! Section 5.2
Target_Number:
Target_Name:
Description:
Level_1: ! Satellite of Sun
Level_2: ! Satellite of Level_1
Level_3: ! Satellite of Level_2
Ephem_Uncert: ! Needed for REQ EPHEM CORR sp req
Acq_Uncert: ! Needed for SAVE and USE OFFSET sp reqs
Window:
Flux: ! Include at least V and B-V
Comments:
Generic_Targets ! Section 5.3
Target_Number:
Target_Name:
Description:
Criteria:
Flux:
Comments:
Scan_Data ! Appendix B
Scan_Number:
FGS_Scan:
Cont_or_Dwell:
Dwell_Points:
Dwell_Secs:
Scan_Width:
Scan_Length:
Sides_Angle:
Number_Lines:
Scan_Rate:
First_Line_PA:
Scan_Frame:
Length_Offset:
Width_Offset:
! This is a template for a single visit containing a single exposure
! Repeat exposure and visit blocks as needed
Visits ! Section 6
Visit_Number:
Visit_Requirements: ! Section 7.1
! Uncomment or copy visit level special requirements needed
! Most of these requirements (including ORIENT) will limit scheduling
! PCS MODE [Fine | Gyro]
! GUIDing TOLerance <angle>
! DROP TO GYRO IF NECESSARY [NO REACQuisition]
! ORIENTation <angle1> TO <angle2>
! ORIENTation <angle1> TO <angle2> FROM <visit>
! ORIENTation <angle1> TO <angle2> FROM NOMINAL
! SAME ORIENTation AS <visit>
! CVZ
! PARallel
! SCHEDulability <percentage>
! AFTER <visit> [BY <time1> [TO <time2>]]
! AFTER <date>
! BEFORE <date>
! BETWEEN <date1> AND <date2>
! GROUP <visit-list> WITHIN <time>
! PERIOD <time> AND ZERO-PHASE <date>
! SEQ <visit-list> WITHIN <time>
! ON HOLD [FOR <visit-list>]
On_Hold_Comments:
Visit_Comments:
Exposure_Number: ! Section 6.5
Target_Name:
Config:
Opmode:
Aperture:
Sp_Element:
Wavelength:
Optional_Parameters:
Number_of_Iterations:
Time_Per_Exposure:
Special_Requirements: ! Section 7.2
! Uncomment or copy exposure level special requirements needed
! INTeractive ACQuisition FOR <exp-list>
! ONBOARD ACQuisition FOR <exp-list>
! SAVE OFFSET <id>
! USE OFFSET <id>
! POSition TARGet <x-value>,<y-value>
! SAME POSition AS <exp>
! DO FOR TARGets <targ-list> ! FGS only
! PARallel WITH <exp>
! GROUP-FGS <exp-list> WITHIN <time>
! SPATIAL SCAN <#> [<exp-list> | SINGLE-EXP ]
! RT ANALYSIS [FOR <exp-list>]
! REQuires UPLINK
! REQuires EPHEMeris CORRection <id>
! END ORBIT
! EXPAND
! LOW-SKY
! MAXimum DURation [<time> | <%>]
! MINimum DURation [<time> | <%>]
! NO SPLIT
! PHASE <number1[0,1]> TO <number2[0,1]>
! SEQuence <exp-list> NON-INTerruptible
! SHADOW
Comments:
Data_Distribution ! Defaults indicated; change if desired
Medium: 8MM ! 8MM or 6250BPI or 1600BPI
Blocking_Factor: 10 ! 10 or 1
! Only astronomers with very old 9-
! track tape drives should consider
! a blocking factor of 1
Ship_To: PI_Address ! STSCI or PI_Address or <free-text>
! PI Address from Phase I is:
!
! 3700 San Martin Dr.
! Baltimore
! 21218
!
!
Ship_Via: UPS ! UPS (2-day) or OVERNIGHT
! Overnight shipping done at PI expense
Recipient_Email: ! Needed if Ship_To: is not PI_Address
! <free-text>
! Let us know what you think of this template and software!
! Please send a list of your likes and dislikes to your Program Coordinator