! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template
! $Id: 6560,v 5.1 1996/06/10 17:41:10 pepsa Exp $
Proposal_Information
Title: Mapping an optical Einstein ring
Proposal_Category: GO
Scientific_Category: COSMOLOGY
Cycle: 6
Investigators
PI_name: Dr. S. J. Warren
PI_Institution: Imperial College of Science Technology and
Medicine
CoI_Name: Dr. P. C. Hewett
CoI_Institution: Institute of Astronomy
Contact:
CoI_Name: Dr. P. Moller
CoI_Institution: Space Telescope Science Institute
Contact:
CoI_Name: Dr. G. F. Lewis
CoI_Institution: Institute of Astronomy
Contact:
Abstract:
Observations of gravitationally lensed Einstein-ring images
provide a dramatic improvement in our ability to constrain the
properties of lensing mass distributions and the structure in
the extended sources. The rings are so effective, relative to
the more common multiply-imaged point sources, because of the
constraints provided by the two-dimensional surface
brightness maps obtained from high-resolution imaging. The
first five known rings were discovered in radio surveys and
are all very faint optically. The first optically bright
ring, recently discovered spectroscopically and confirmed by
imaging, is clearly a prime target for HST imaging. Here we
propose a WFPC2 image through the F555W
filter to provide a resolved surface-brightness map of the
ring and the lensing galaxy. The lens is an early-type galaxy
at z=0.485, and the source is an emission-line galaxy at
z=3.591. The goal of these observations is
twofold: a) to measure the radial profile of the mass-to-light
ratio of the lensing galaxy, and b) to determine the
structure of the background high-redshift galaxy, at a
resolution of 0.2 arcsec.
Questions
Observing_Description:
Four orbits broad band V imaging of the same target, comprising
eight dithered images.
Real_Time_Justification:
Calibration_Justification:
Additional_Comments:
Our original request was for 16 orbits with the F547M filter, which
is optimal for imaging the ring itself. Instead we were awarded only 4 orbits
to obtain the surface brightness profile of the lensing galaxy. This is
better achieved with the broader F555W filter, which we have therefore selected.
Fixed_Targets
Target_Number: 1
Target_Name: GAL-004942-275226
Alternate_Names:
Description: GALAXY,ELLIPTICAL,GRAVITATIONAL LENS,EINSTEIN RING,
Position: RA=0H 49M 41.80S +/- 0.10S,DEC=-27D 52' 26.0" +/- 1.0",
PLATE-ID=025A
Equinox: J2000
RV_or_Z: Z=0.485
RA_PM: 0.0
Dec_PM: 0.0
Epoch:
Annual_Parallax: 0.0
Flux: V=20.4
B-V=1.5
Comments:
Solar_System_Targets
Generic_Targets
Scan_Data
Visits
Visit_Number: 1
Visit_Requirements: ORIENT 45.0D TO 90.0D
On_Hold_Comments:
Visit_Comments: The purpose of the orientation requirement is
to image a second galaxy in WF3. The position of this second galaxy
relative to the target galaxy is distance 58 arcsec, and position angle
201 deg. With this range of orientation the second galaxy image should
not be affected by charge bleeding or diffraction spikes from a bright
star that will also lie in WF3.
Exposure_Number: 1
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements:
Comments:
Exposure_Number: 2
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements:
Comments:
Exposure_Number: 3
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements: POS TARG +0.5,+0.25
Comments:
Exposure_Number: 4
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements: POS TARG +0.5,+0.25
Comments:
Exposure_Number: 5
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements: POS TARG +0.75,+0.75
Comments:
Exposure_Number: 6
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements: POS TARG +0.75,+0.75
Comments:
Exposure_Number: 7
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements: POS TARG +0.25,+0.5
Comments:
Exposure_Number: 8
Target_Name: GAL-004942-275226
Config: WFPC2
Opmode: IMAGE
Aperture: WF4-FIX
Sp_Element: F555W
Wavelength:
Optional_Parameters: CR-SPLIT=NO
Number_of_Iterations: 1
Time_Per_Exposure: 1200.00S
Special_Requirements: POS TARG +0.25,+0.5
Comments:
Data_Distribution
Medium: 8MM
Blocking_Factor: 10
Ship_To: PI_Address
Ship_Via: UPS
Recipient_Email: