! 5919_v3.prop
! Revised by Ray Lucas, 8 December, 1995.
! Comments added to Exp Log lines and General Form text. Also removed
! semicolons etc. from special requirements and placed them on separate
! lines for better readability. Also added visit level comments.
! Closed ORIENT range down to exactly 227.32D by making both values in
! the range equal to the same value, which was the same value for the U3
! ORIENT ( PA_V3+180D ) used in the Early Release program 5190 in January
! 1994.
!
! Set all exposure times to 2800s ( equivalent to turning off the EXPAND
! feature for all but the initial exposure of both SUs, which were originally
! 2500s each, but were EXPANDed by TRANS to 2800s each ). This was done to
! try to make SU 01 schedulable and to try to give SU 02 more schedulability
! than the very minimal schedulability it originally had in the flight
! database in the original version of the program. - RAL - 11 December, 1995
!
! Proposal 5919, submission 1
! PI: Francesco Bertola
! Received Tue Mar 7 12:50:15 EST 1995
! From: lbuson@eso.org
! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template
! $Id: 5919,v 4.1 1995/12/11 22:05:26 pepsa Exp $
Proposal_Information
Title: UV EVOLUTION OF GALAXIES IN A DISTANT
CLUSTER
Proposal_Category: GO
Scientific_Category: Galaxies & Clusters
Cycle: 5
Investigators
PI_name: Francesco Bertola
PI_Institution: University of Padova
CoI_Name: Lucio Buson
CoI_Institution: Osservatorio Astronomico di Padova
Contact: Y
CoI_Name: Cesare Chiosi
CoI_Institution: University of Padova
Contact: N
CoI_Name: Alan Dressler
CoI_Institution: Carnegie Observatories
Contact: N
CoI_Name: Augustus Oemler
CoI_Institution: Yale University
Contact: N
Abstract:
It is proposed to image in two properly spaced UV passbands
(rest frame wavelength 1500 Angstrom and 2000 Angstrom) the
very rich galaxy cluster CL0939+4713 = Abell 851 at a redshift
of z=0.41. Such a cluster, which represents a lookback time of
4--5 billion yr in conventional cosmologies, contains a large
population of galaxies with strong ongoing star formation.
Moreover, already existing HST images corresponding to a rest
frame color between Johnson B and V, reveal an abundance of
late--type galaxies as well as many merging or interacting
systems. The new UV observations proposed here are primarily
intended to test the current ideas on the age and metal
abundance of distant systems. In particular we plan to measure
at z=0.4 the level of the well--known UV turn--up observed in
present--day ellipticals and spiral bulges. The level of this
turn--up is expected to decrease with lookback time. Its
precise determination at a given z will allow us to put strict
constraints on the evolutionary history of these galaxies. As
a by--product it is expected to derive essential clues on the
nature of a cluster of faint objects surrounding a quasar at
z=2.055 contained in the field. Since the proposed
observations will sample a wavelength below the Lyman limit
for z=2 and z=1.2 respectively, it is expected to see a strong
drop in flux for these objects depending on their redshift,
thus possibly confirming their association with the quasar
itself.
Questions
Observing_Description:
Cluster galaxies in our proposed field are as bright as V=20,
but to reach a significant number of detected objects one has
to go down at least to the characteristic magnitude of the
luminosity function. As a consequence we have chosen V~23 as
the limit to which one has to try to get good detections. Our
estimate of the exposure times comes from the expected
electrons detected from WFPC-2, as described in Sec. 6 of the
WFPC-2 Instrument Handbook. On the basis of the model SEDs
provided in Fig. 2 one can assume that an object at z=0.4
will show in the observer rest frame a drop (when compared
to V) of ~3 mag at Lambda~ 3000 Angstrom and a subsequent
rise of ~1.5 mag at Lambda~ 2000 Angstrom. Even if the lower
efficiency of the F218W filter will be partially compensated
by the above rise in UV flux at shorter wavelengths, we
expect to collect twice the electrons per single orbit
exposure (~200) in the F300W filter with respect to the
shorter wavelength F218W filter. As a consequence, we
estimate that, in order to study at least 30--50 galaxies we
will need a minimum exposure of 10 orbits in the F218W filter
and 5 orbits in the F300W filter (15 in total).
Real_Time_Justification:
None.
Calibration_Justification:
None.
Additional_Comments:
Please use SAME GUIDE STARS for both visits if possible. The
GROUP 1-2 WITHIN 7 Days may be relaxed for scheduling as long as
the SAME ORIENT ( and preferably also the SAME GUIDE STARS if
possible ) are maintained for both visits. The absolute ORIENT
value exactly matches that used in the Early Release program 5190
done in January 1994. This value is U3 ORIENT 227.32D which
corresponds to 180D plus the PA_V3 value in the headers of the
program 5190 data, e.g. 5190 PA_V3=47.32 and U3 ORIENT = PA_V3+180D,
so U3 ORIENT for both programs should be 47.32+180 = 227.32D.
Fixed_Targets
Target_Number: 1
Target_Name: ABELL851
Description: CLUSTER OF GALAXIES, Rich Cluster
Position: RA=9H 39M 48.0S +/- 0.1S, DEC=+47D 12' 41.0" +/- 1"
Equinox: 1950.0
RV_or_Z: Z=0.41
Flux: SURF(V)=23.0 +/- 1.0, B-V=1.3 +/- 0.3
Comments: The field contains many faint galaxies in the range 21< V <25.
Visits
Visit_Number: 1
Visit_Requirements: ORIENT 227.32D TO 227.32D
Visit_Comments: Make use of the SAME GUIDE STARS for both visits, if
possible. Do both visits at the SAME ORIENT. GROUP 1-2
WITHIN 7 Days requirement may be relaxed for scheduling
as long as SAME ORIENT ( and also SAME GUIDE STARS if
possible ) maintained for both visits.
Exposure_Number: 1
Target_Name: ABELL851
Config: WFPC2
Opmode: IMAGE
Aperture: WFALL-FIX
Sp_Element: F218W
Wavelength: 2159
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 2800S
Special_Requirements: POS TARG +10,+10
MIN DUR 2500S
END ORBIT
Comments: WFALL-FIX with POS TARG +10,+10 places Fixed Target List
coordinate position ~at apex of the WFPC2 pyramid.
Exposure_Number: 2
Target_Name: ABELL851
Config: WFPC2
Opmode: IMAGE
Aperture: WFALL-FIX
Sp_Element: F218W
Wavelength: 2159
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 4
Time_Per_Exposure: 2800S
Special_Requirements: SAME POS AS 1
MIN DUR 2800S
END ORBIT
Comments: Do at WFALL-FIX with POS TARG +10,+10 as in first
exposure of this visit.
Exposure_Number: 3
Target_Name: ABELL851
Config: WFPC2
Opmode: IMAGE
Aperture: WFALL-FIX
Sp_Element: F300W
Wavelength: 2911
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 3
Time_Per_Exposure: 2800S
Special_Requirements: SAME POS AS 1
MIN DUR 2800S
END ORBIT
Comments: Do at WFALL-FIX with POS TARG +10,+10 as in first
exposure of this visit.
Visit_Number: 2
Visit_Requirements: SAME ORIENT AS 1
GROUP 1-2 WITHIN 7D
Visit_Comments: Make use of the SAME GUIDE STARS for both visits, if
possible. Do both visits at the SAME ORIENT. GROUP 1-2
WITHIN 7 Days requirement may be relaxed for scheduling
as long as SAME ORIENT ( and also SAME GUIDE STARS if
possible ) maintained for both visits.
Exposure_Number: 1
Target_Name: ABELL851
Config: WFPC2
Opmode: IMAGE
Aperture: WFALL-FIX
Sp_Element: F218W
Wavelength: 2159
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 2800S
Special_Requirements: POS TARG +10.5,+10.5
MIN DUR 2500S
END ORBIT
Comments: WFALL-FIX with POS TARG +10.5,+10.5 places Fixed Target
List coordinate position ~0.5 arcsec from apex of WFPC2
pyramid in both x and y.
Exposure_Number: 2
Target_Name: ABELL851
Config: WFPC2
Opmode: IMAGE
Aperture: WFALL-FIX
Sp_Element: F218W
Wavelength: 2159
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 4
Time_Per_Exposure: 2800S
Special_Requirements: SAME POS AS 1
MIN DUR 2800S
END ORBIT
Comments: Do at WFALL-FIX with POS TARG +10.5,+10.5 as in first
exposure of this visit.
Exposure_Number: 3
Target_Name: ABELL851
Config: WFPC2
Opmode: IMAGE
Aperture: WFALL-FIX
Sp_Element: F300W
Wavelength: 2911
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 2
Time_Per_Exposure: 2800S
Special_Requirements: SAME POS AS 1
MIN DUR 2800S
END ORBIT
Comments: Do at WFALL-FIX with POS TARG +10.5,+10.5 as in first
exposure of this visit.
Data_Distribution
Medium: 6250BPI
Blocking_Factor: 10
Ship_To: PI_Address
Ship_Via: UPS