12931(  4) - 06-May-2013 15:11:15 - [  1]

                  HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12931

Version:   4  Check-in Time: 06-May-2013 15:11:15       STScI Edit Number: 0     

Title
Ultra-Faint Galaxies at the Peak Epoch of Star Formation                        
------------------------------------------------------------------------------------
Type             Cycle
GO               20       
------------------------------------------------------------------------------------
Investigators                                                                   
                                                                                     Contact?
    PI: Prof. Brian Siana                 University of California - Riverside          Y 
   CoI: Dr. Johan Richard                 Centre de Recherche Astronomique de Lyon      N 
   CoI: Dr. Daniel P. Stark               University of Arizona                         N 
   CoI: Prof. Claudia Scarlata            University of Minnesota - Twin Cities         N 
   CoI: Dr. Harry Teplitz                 California Institute of Technology            N 
   CoI: Prof. Brant Robertson             University of Arizona                         N 
   CoI: Mrs. Anahita Alavi                University of California - Riverside          N 
   CoI: Dr. Alberto Dominguez             University of California - Riverside          N 
   CoI: Dr. Vandana Desai                 Jet Propulsion Laboratory                     N 

------------------------------------------------------------------------------------
Abstract

There has been much recent interest in the ultra-faint galaxies that are near or    
beyond our current detection limits at z>1. These galaxies are likely responsible   
for reionizing the intergalactic medium and make up a significant fraction of the   
global star formation rate density. Unfortunately, we can not study them in detail  
as they are too faint (27 < V < 30) for morphological studies or follow-up          
spectroscopy. With previous UVIS F275W imaging, we have demonstrated that we can    
efficiently select ultra-faint galaxies at z~2 by using magnification from strong   
gravitational lensing by the massive cluster Abell 1689. This unique cluster offers 
the largest area with high magnifications (1.5-4 magnitudes). We selected 81        
galaxies at 1.7<z<2.3 behind Abell 1689, extending the previous luminosity function 
a factor of 100x fainter.                                                           
                                                                                    
We propose to extend this study to a much broader redshift range. 10 orbits of F225W
and 16 orbits of F336W imaging will allow identification of 50-100 ultra-faint      
star-forming (SFR < 0.1 M_sol/yr) galaxies at each of the two target redshifts,     
1<z<1.7 and 2.3<z<3.0, respectively. The high magnification of these samples enables
ultra-high resolution (<100 pc) morphologies as well as rest-frame UV and optical   
spectroscopy from the ground.                                                       
                                                                                    
We will extend the measurement of the faint-end of the UV luminosity function       
30-100x fainter than before and measure the evolution of the faint-end slope from   
1<z<3, allowing the ultimate determination of the global star formation rate density
at the epoch of peak star formation. Finally, we will measure the Lyman continuum   
escape fraction in these galaxies that are analogous to those that reionized the    
universe.                                                                           
------------------------------------------------------------------------------------

  Observations Description
  ------------------------

     The program will obtain 16 orbits of UVIS F336W and 10 orbits of F225W imaging 
     of a single pointing centered on the lensing cluster Abell 1689. We will use   
                                                  12931(  4) - 06-May-2013 15:11:15 - [  2]

     half-orbit exposures to reduce read noise. There are plenty of exposures to    
     remove the significant number of cosmic rays in half-orbit exposures.          
                                                                                    
     We will use the WFC3-UVIS-DITHER-BOX pattern with sub-pixel dithering to allow 
     us to reconstruct the PSF at higher resolution. Because of recent degradation  
     in the CTE, we will be using the post-flash LED to add background to each image
     to get us to an average background of 13 e-, including dark and background.    
     This requires 8 and 11 e- flashes in F336W and F225W, respectively.            
                                                                                    
     For each filter, we obtain images with orientation rotations of approximately  
     90 degrees. This will allow us to assess the magnitude of CTE issues at the    
     faint end, as many objects will lie near the readout edge at one orientation   
     and far from the readout edge at the other orientation.                        

  Real Time Justification
  -----------------------

                                                                                    

  Calibration Justification
  -------------------------

                                                                                    

  Additional Comments
  -------------------

                                                                                    
------------------------------------------------------------------------------------

                                                  12931(  4) - 06-May-2013 15:11:15 - [  3]

TARGET LIST    Fixed Targets
------------------------------------------------------------------------------------------------------------------------------------
Tar|   Target   |         Target        |            Target              |Coord   | Radial |             Flux data
No |    Name    |       Description     |           Position             |Eqnx    |  Vel.  |
------------------------------------------------------------------------------------------------------------------------------------
2   ABELL-1689   CLUSTER OF GALAXIES,    RA=13H11M30.0000S +/- 0.1",      J2000             V = 27                                  
                 GRAVITATIONAL LENS,     DEC=-01D20'31.00" +/- 0.1"                                                                 
                 RICH CLUSTER                                                                                                       
    Reference Frame: ICRS
    Comments: This object was generated by the targetselector and         
              retrieved from the SIMBAD database.                         
------------------------------------------------------------------------------------------------------------------------------------
                                                  12931(  4) - 06-May-2013 15:11:15 - [  4]

Patterns
------------------------------------------------------------------------------------------------------------------------------------
Pattern_Number: 1

                    Primary_Pattern                   Secondary_Pattern                
Pattern_Type        WFC3-UVIS-DITHER-BOX                                               
Pattern_Purpose     DITHER                                                             
Number_Of_Points    4                                                                  
Point_Spacing       0.173                                                              
Line_Spacing        0.112                                                              
Coordinate_Frame    POS-TARG                                                           
Pattern_Orient      23.884                                                             
Angle_Between_Sides 81.785                                                             
Center_Pattern      NO                                                                 

------------------------------------------------------------------------------------------------------------------------------------
Pattern_Number: 2

                    Primary_Pattern                   Secondary_Pattern                
Pattern_Type        WFC3-UVIS-DITHER-LINE                                              
Pattern_Purpose     DITHER                                                             
Number_Of_Points    2                                                                  
Point_Spacing       0.145                                                              
Line_Spacing        <none>                                                             
Coordinate_Frame    POS-TARG                                                           
Pattern_Orient      46.84                                                              
Angle_Between_Sides <none>                                                             
Center_Pattern      NO                                                                 

------------------------------------------------------------------------------------------------------------------------------------
                                                  12931(  4) - 06-May-2013 15:11:15 - [  5]

Visit: 01
     Visit Requirements:  SCHED 100%; ORIENT 117D TO 117 D                                                            
     On Hold Comments:    <none>                                                                                      
     Additional Comments: <none>                                                                                      


Exposures
------------------------------------------------------------------------------------------------------------------------------------
Exp |   Target  | Instr  | Oper. | Aper    |Spectral|Central|           Optional           |Num|   Time   |       Special
Num |    Name   | Config | Mode  | or FOV  |Element |Waveln.|          Parameters          |Exp|          |     Requirements
------------------------------------------------------------------------------------------------------------------------------------
1    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F336W            FLASH=4.0                      1   2670 S     POS TARG -0.21, -0.97;   
                 S                ER                                                                       PATTERN 1 1              
------------------------------------------------------------------------------------------------------------------------------------

Sub Exposures
------------------------------------------------------------------------------------------------------------------------------------
Target             | Exp |Instr   | Oper. |  Aper  |Spectral|Cent.|Primary     |Secondary   |Iteration |CR-SPLIT  |Orbit  |Duration
Name               | Num |Config  | Mode  | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num       |Num       |Number |
------------------------------------------------------------------------------------------------------------------------------------
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          1            none         none       none       1       N/A      
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          2            none         none       none       2       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          3            none         none       none       3       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          4            none         none       none       4       2785.0 S 
                          S                TER                                                                                      
                                                  12931(  4) - 06-May-2013 15:11:15 - [  6]

Visit: 02
     Visit Requirements:  SCHED 100%; SAME ORIENT AS 01                                                               
     On Hold Comments:    <none>                                                                                      
     Additional Comments: <none>                                                                                      


Exposures
------------------------------------------------------------------------------------------------------------------------------------
Exp |   Target  | Instr  | Oper. | Aper    |Spectral|Central|           Optional           |Num|   Time   |       Special
Num |    Name   | Config | Mode  | or FOV  |Element |Waveln.|          Parameters          |Exp|          |     Requirements
------------------------------------------------------------------------------------------------------------------------------------
1    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F336W            FLASH=4.0                      1   2670 S     POS TARG 0.21, 0.97;     
                 S                ER                                                                       PATTERN 2 1              
------------------------------------------------------------------------------------------------------------------------------------
2    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F275W            FLASH=11.0                     1   1300 S     POS TARG 0.00, 0.00;     
                 S                ER                                                            see below  PATTERN 1 2              
------------------------------------------------------------------------------------------------------------------------------------

Sub Exposures
------------------------------------------------------------------------------------------------------------------------------------
Target             | Exp |Instr   | Oper. |  Aper  |Spectral|Cent.|Primary     |Secondary   |Iteration |CR-SPLIT  |Orbit  |Duration
Name               | Num |Config  | Mode  | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num       |Num       |Number |
------------------------------------------------------------------------------------------------------------------------------------
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          1            none         none       none       1       N/A      
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          2            none         none       none       2       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          2     WFC3/UVI ACCUM   UVIS-CEN F275W          1            none         none       none       3       1325.0 S 
                          S                TER                                                                                      
ABELL-1689          2     WFC3/UVI ACCUM   UVIS-CEN F275W          2            none         none       none       3       1325.0 S 
                          S                TER                                                                                      
ABELL-1689          2     WFC3/UVI ACCUM   UVIS-CEN F275W          3            none         none       none       4       1325.0 S 
                          S                TER                                                                                      
ABELL-1689          2     WFC3/UVI ACCUM   UVIS-CEN F275W          4            none         none       none       4       1325.0 S 
                          S                TER                                                                                      
                                                  12931(  4) - 06-May-2013 15:11:15 - [  7]

Visit: 03
     Visit Requirements:  SCHED 100%; ORIENT 201D TO 214 D                                                            
     On Hold Comments:    <none>                                                                                      
     Additional Comments: <none>                                                                                      


Exposures
------------------------------------------------------------------------------------------------------------------------------------
Exp |   Target  | Instr  | Oper. | Aper    |Spectral|Central|           Optional           |Num|   Time   |       Special
Num |    Name   | Config | Mode  | or FOV  |Element |Waveln.|          Parameters          |Exp|          |     Requirements
------------------------------------------------------------------------------------------------------------------------------------
1    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F336W                                           1   2670 S     POS TARG -0.21, -0.97;   
                 S                ER                                                                       PATTERN 1 1              
------------------------------------------------------------------------------------------------------------------------------------

Sub Exposures
------------------------------------------------------------------------------------------------------------------------------------
Target             | Exp |Instr   | Oper. |  Aper  |Spectral|Cent.|Primary     |Secondary   |Iteration |CR-SPLIT  |Orbit  |Duration
Name               | Num |Config  | Mode  | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num       |Num       |Number |
------------------------------------------------------------------------------------------------------------------------------------
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          1            none         none       none       1       N/A      
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          2            none         none       none       2       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          3            none         none       none       3       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          4            none         none       none       4       2785.0 S 
                          S                TER                                                                                      
                                                  12931(  4) - 06-May-2013 15:11:15 - [  8]

Visit: 04
     Visit Requirements:  SCHED 100%; SAME ORIENT AS 03                                                               
     On Hold Comments:    <none>                                                                                      
     Additional Comments: <none>                                                                                      


Exposures
------------------------------------------------------------------------------------------------------------------------------------
Exp |   Target  | Instr  | Oper. | Aper    |Spectral|Central|           Optional           |Num|   Time   |       Special
Num |    Name   | Config | Mode  | or FOV  |Element |Waveln.|          Parameters          |Exp|          |     Requirements
------------------------------------------------------------------------------------------------------------------------------------
1    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F336W                                           1   2670 S     POS TARG 0.21, 0.97;     
                 S                ER                                                                       PATTERN 1 1              
------------------------------------------------------------------------------------------------------------------------------------

Sub Exposures
------------------------------------------------------------------------------------------------------------------------------------
Target             | Exp |Instr   | Oper. |  Aper  |Spectral|Cent.|Primary     |Secondary   |Iteration |CR-SPLIT  |Orbit  |Duration
Name               | Num |Config  | Mode  | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num       |Num       |Number |
------------------------------------------------------------------------------------------------------------------------------------
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          1            none         none       none       1       N/A      
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          2            none         none       none       2       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          3            none         none       none       3       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F336W          4            none         none       none       4       2785.0 S 
                          S                TER                                                                                      
                                                  12931(  4) - 06-May-2013 15:11:15 - [  9]

Visit: 05
     Visit Requirements:  SCHED 100%; SAME ORIENT AS 01                                                               
     On Hold Comments:    <none>                                                                                      
     Additional Comments: <none>                                                                                      


Exposures
------------------------------------------------------------------------------------------------------------------------------------
Exp |   Target  | Instr  | Oper. | Aper    |Spectral|Central|           Optional           |Num|   Time   |       Special
Num |    Name   | Config | Mode  | or FOV  |Element |Waveln.|          Parameters          |Exp|          |     Requirements
------------------------------------------------------------------------------------------------------------------------------------
1    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F225W            FLASH=11.0                     1   2670 S     PATTERN 1 1              
                 S                ER                                                                                                
------------------------------------------------------------------------------------------------------------------------------------
2    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F225W            FLASH=11.0                     1   2780 S     POS TARG -0.22, -1.54    
                 S                ER                                                                                                
------------------------------------------------------------------------------------------------------------------------------------

Sub Exposures
------------------------------------------------------------------------------------------------------------------------------------
Target             | Exp |Instr   | Oper. |  Aper  |Spectral|Cent.|Primary     |Secondary   |Iteration |CR-SPLIT  |Orbit  |Duration
Name               | Num |Config  | Mode  | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num       |Num       |Number |
------------------------------------------------------------------------------------------------------------------------------------
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          1            none         none       none       1       N/A      
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          2            none         none       none       2       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          3            none         none       none       3       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          4            none         none       none       4       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          2     WFC3/UVI ACCUM   UVIS-CEN F225W          none         none         none       none       5       N/A      
                          S                TER                                                                                      
                                                  12931(  4) - 06-May-2013 15:11:15 - [ 10]

Visit: 06
     Visit Requirements:  SCHED 100%; SAME ORIENT AS 03                                                               
     On Hold Comments:    <none>                                                                                      
     Additional Comments: <none>                                                                                      


Exposures
------------------------------------------------------------------------------------------------------------------------------------
Exp |   Target  | Instr  | Oper. | Aper    |Spectral|Central|           Optional           |Num|   Time   |       Special
Num |    Name   | Config | Mode  | or FOV  |Element |Waveln.|          Parameters          |Exp|          |     Requirements
------------------------------------------------------------------------------------------------------------------------------------
1    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F225W            FLASH=11.0                     1   2670 S     PATTERN 1 1              
                 S                ER                                                                                                
------------------------------------------------------------------------------------------------------------------------------------
2    ABELL-1689  WFC3/UVI ACCUM   UVIS-CENT F225W            FLASH=11.0                     1   2780 S     POS TARG -0.22, -1.54    
                 S                ER                                                                                                
------------------------------------------------------------------------------------------------------------------------------------

Sub Exposures
------------------------------------------------------------------------------------------------------------------------------------
Target             | Exp |Instr   | Oper. |  Aper  |Spectral|Cent.|Primary     |Secondary   |Iteration |CR-SPLIT  |Orbit  |Duration
Name               | Num |Config  | Mode  | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num       |Num       |Number |
------------------------------------------------------------------------------------------------------------------------------------
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          1            none         none       none       1       N/A      
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          2            none         none       none       2       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          3            none         none       none       3       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          1     WFC3/UVI ACCUM   UVIS-CEN F225W          4            none         none       none       4       2785.0 S 
                          S                TER                                                                                      
ABELL-1689          2     WFC3/UVI ACCUM   UVIS-CEN F225W          none         none         none       none       5       N/A      
                          S                TER                                                                                      
                                                  12931(  4) - 06-May-2013 15:11:15 - [ 11]

            Summary Form for Proposal  12931

  Item                         Used in this proposal                                                                              
------------------------------------------------------------------------------------------------------------------------------------
  Apertures                    UVIS-CENTER                                                                                         
------------------------------------------------------------------------------------------------------------------------------------
  Configurations               WFC3/UVIS                                                                                           
------------------------------------------------------------------------------------------------------------------------------------
  Opmodes                      ACCUM                                                                                               
------------------------------------------------------------------------------------------------------------------------------------
  Optional Parameters          FLASH=11.0, FLASH=4.0                                                                               
------------------------------------------------------------------------------------------------------------------------------------
  Special Requirements         ORIENT 117D TO 117 D, ORIENT 201D TO 214 D, PATTERN 1 1, PATTERN 1 2, PATTERN 2 1, POS TARG -0.21,  
                               -0.97, POS TARG -0.22, -1.54, POS TARG 0.00, 0.00, POS TARG 0.21, 0.97, SAME ORIENT AS 01, SAME     
                               ORIENT AS 03, SCHED 100%                                                                            
------------------------------------------------------------------------------------------------------------------------------------
  Spectral Elements            F225W, F275W, F336W                                                                                 
------------------------------------------------------------------------------------------------------------------------------------
  Target Names                 ABELL-1689                                                                                          
------------------------------------------------------------------------------------------------------------------------------------