13291( 3) - 22-Jul-2013 15:07:28 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13291 Version: 3 Check-in Time: 22-Jul-2013 15:07:28 STScI Edit Number: 0 Title Resolving internal structures of the progenitors of early-type galaxies in a vigorously forming cluster at z=2.5 ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Masao Hayashi University of Tokyo, Institute of Cosmic Y Ray Research CoI: Dr. Tadayuki Kodama National Astronomical Obs of Japan (NAOJ), N Subaru Telescope CoI: Mr. Ken-ichi Tadaki University of Tokyo N CoI: Dr. Yusei Koyama University of Durham N CoI: Dr. Ichi Tanaka National Astronomical Obs of Japan (NAOJ), N Subaru Telescope CoI: Mr. Rhythm Shimakawa Graduate University for Advanced Studies N ------------------------------------------------------------------------------------ Abstract In our recent near-infrared narrow-band imaging surveys, we have identified the densest complex of Halpha emitters associated to a radio galaxy at z=2.5. Together with a large statistical excess of massive red galaxies (Distant Red Galaxies: DRGs), this region is probably the best candidate of a proto-cluster which is destined to evolve to a rich galaxy cluster today dominated by early-type galaxies. Therefore we are surely witnessing the clustered vigorous formation of the progenitors of present-day early-type galaxies. As such, this proto-cluster serves us the unique opportunity to investigate the physical processes in their formation and early evolution, and its environmental dependence for the first time. Note that because our targets are strongly clustered, we can efficiently make a statistical sample with a small number of pointings hence a relatively short investment of time. By spatially resolving the morphologies and internal structures of these galaxies by the proposed high-resolution HST imaging with ACS/F814W and WFC3/F160W, we will focus on the following critical issues; (1) first appearance of the morphology-density relation, (2) identification of the progenitors of massive, quiescent, compact galaxies, (3) environmental dependence of the mass-size relation, and (4) frequency of clumps/mergers and the mode of star formation (compactness/dustiness). The proposed observations will shed light on the physical processes "in action" on the progenitors of massive early-type galaxies in clusters for the first time. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will conduct the primary observation in the proto-cluster USS 1558-003 at z=2.53 in 3 pointings with WFC3/IR and F160W filter and in 2 pointings with ACS/WFC and F814W filter. To fully cover the three groups where Halpha emitters (HAEs) and DRGs are clustered without any space, we request the observation conducting all the exposures with the specific values of ORIENT. 13291( 3) - 22-Jul-2013 15:07:28 - [ 2] We request 5 visits with 2 orbits each. Our priority of the visits is as follows; (1st) POS3 with WFC3, (2nd) POS5 with ACS, (3rd) POS2 with WFC3, (4th) POS4 with ACS, and (5th) POS1 with WFCS3. As described in scientific justification of phase-I proposal, one of our main objectives is to measure the profile of stellar component and then derive the morphology and size of HAEs in the proto-cluster environment at z=2.53. We require the depth of at least ~27.5 (27.0) ABmag in ACS/F814W (WFC3/F160W) for point source, respectively, which are comparable to the wide survey data of CANDELS. The required depth is justified by the paper of van der Wel et al. (2012). They measured the structural parameters of H(F160W)-selected galaxies by fitting Sersic profile to CANDELS data, and investigated systematic and random uncertainties in structural parameters as a function of H(F160W) magnitude of galaxy for CANDELS wide survey data. According to Table 3 of van der Wel et al. (2012), structural parameters can be measured accurately for star-forming galaxies with Sersic index n<3 down to 25 ABmag in H(F160W). Therefore, the depth comparable to the CANDELS data is crucial to accomplish our objectives. According to Exposure Time Calculators, 5000 sec on-source exposure with ACS/F814W reaches 27.4 ABmag in 5-sigma for point source in the case measured within a 0.25''-radius aperture, while 4520 sec on-source exposure with WFC3/F160W reaches 27.0 ABmag in 5-sigma. The estimation is conducted under the assumption of the background levels that standard zodical (earth shine) light normalizations is average. Since our target is located at declination of -00:28:48.0, it can be observed for 54 minutes per one orbit. Thus, taking account of the orbit visibility, the required exposure time per one pointing in ACS/F814W (WFC3/F160W) is 5000 (5208) seconds in total with 4 exposures in 4 dithered points, respectively, which requires the 2 orbits per one pointing in both ACS/F814W and WFC3/F160W. Note that obtaining as deep near-infrared data as possible is desirable for us to measure the structural parameters of stellar component for less massive HAEs at z=2.53. We also make sure that almost all of HAEs we have found in the proto-cluster have magnitudes ranging between 21.7-25.0 ABmag in z'-band (Subaru/Suprime-Cam) and 20.0-24.5 ABmag in H-band (Subaru/MOIRCS). Regarding the Charge Transfer Efficiency (CTE) effect, we make sure that the estimated background of ACS images is greater than 20 electrons for the exposure time we plan. We will conduct a standard calibration, so no data is required for special calibration. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments 13291( 3) - 22-Jul-2013 15:07:28 - [ 3] ------------------- ------------------------------------------------------------------------------------ 13291( 3) - 22-Jul-2013 15:07:28 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 USS1558-003- CLUSTER OF GALAXIES, RA=16H01M17.5480S +/- 0.1", J2000 Magnitudes for our main targets, POS1 HIGH REDSHIFT CLUSTER DEC=-00D27'25.60" +/- 0.1" Halpha emitters at z=2.53, range between 21.7-25.0 ABmag in z'-band and 20.0-24.5 ABmag in H-band. Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 USS1558-003- CLUSTER OF GALAXIES, RA=16H01M17.6170S +/- 0.1", J2000 Magnitudes for our main targets, POS2 HIGH REDSHIFT CLUSTER DEC=-00D29'21.55" +/- 0.1" Halpha emitters at z=2.53, range between 21.7-25.0 ABmag in z'-band and 20.0-24.5 ABmag in H-band. Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 USS1558-003- CLUSTER OF GALAXIES, RA=16H01M12.3350S +/- 0.1", J2000 Magnitudes for our main targets, POS3 HIGH REDSHIFT CLUSTER DEC=-00D30'58.40" +/- 0.1" Halpha emitters at z=2.53, range between 21.7-25.0 ABmag in z'-band and 20.0-24.5 ABmag in H-band. Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 USS1558-003- CLUSTER OF GALAXIES, RA=16H01M16.3930S +/- 0.1", J2000 Magnitudes for our main targets, POS4 HIGH REDSHIFT CLUSTER DEC=-00D28'4.43" +/- 0.1" Halpha emitters at z=2.53, range between 21.7-25.0 ABmag in z'-band and 20.0-24.5 ABmag in H-band. Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 USS1558-003- CLUSTER OF GALAXIES, RA=16H01M14.2340S +/- 0.1", J2000 Magnitudes for our main targets, POS5 HIGH REDSHIFT CLUSTER DEC=-00D31'0.88" +/- 0.1" Halpha emitters at z=2.53, range between 21.7-25.0 ABmag in z'-band and 20.0-24.5 ABmag in H-band. Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13291( 3) - 22-Jul-2013 15:07:28 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG Pattern_Orient 20.67 Angle_Between_Sides 69.05 Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BLOB WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER DITHER Number_Of_Points 2 4 Point_Spacing 5.183 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 41.859 18.528 Angle_Between_Sides 74.653 Center_Pattern YES NO ------------------------------------------------------------------------------------------------------------------------------------ 13291( 3) - 22-Jul-2013 15:07:28 - [ 6] Visit: 01 Visit Requirements: ORIENT 135D TO 135 D; ORIENT 315D TO 315 D On Hold Comments: Additional Comments: In this visit, the WFC3 observations with F160W are carried out at three pointings. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 USS1558-003 WFC3/IR MULTIAC IR-FIX F160W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 3 1 -POS3 CUM (5223.505 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 1 1 none none 1 N/A CUM USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 1 2 none none 1 N/A CUM USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 1 3 none none 1 N/A CUM USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 1 4 none none 1 N/A CUM USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 2 1 none none 2 N/A CUM USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 2 2 none none 2 N/A CUM USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 2 3 none none 2 N/A CUM USS1558-003-POS3 1 WFC3/IR MULTIAC IR-FIX F160W 2 4 none none 2 N/A CUM 13291( 3) - 22-Jul-2013 15:07:28 - [ 7] Visit: 02 Visit Requirements: ORIENT 90D TO 90 D; ORIENT 270D TO 270 D; ORIENT 0D TO 0 D; ORIENT 180D TO 180 D On Hold Comments: Additional Comments: In this visit, the ACS observations with F814W are carried out at two pointings. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 USS1558-003 ACS/WFC ACCUM WFCENTER F814W 1 1250 S PATTERN 2 1 -POS5 (5000 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ USS1558-003-POS5 1 ACS/WFC ACCUM WFCENTER F814W 1 none none none 1 N/A USS1558-003-POS5 1 ACS/WFC ACCUM WFCENTER F814W 2 none none none 1 N/A USS1558-003-POS5 1 ACS/WFC ACCUM WFCENTER F814W 3 none none none 2 N/A USS1558-003-POS5 1 ACS/WFC ACCUM WFCENTER F814W 4 none none none 2 N/A 13291( 3) - 22-Jul-2013 15:07:28 - [ 8] Visit: 03 Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: In this visit, the WFC3 observations with F160W are carried out at three pointings. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 USS1558-003 WFC3/IR MULTIAC IR-FIX F160W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 3 1 -POS2 CUM (5223.505 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 1 1 none none 1 N/A CUM USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 1 2 none none 1 N/A CUM USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 1 3 none none 1 N/A CUM USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 1 4 none none 1 N/A CUM USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 2 1 none none 2 N/A CUM USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 2 2 none none 2 N/A CUM USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 2 3 none none 2 N/A CUM USS1558-003-POS2 1 WFC3/IR MULTIAC IR-FIX F160W 2 4 none none 2 N/A CUM 13291( 3) - 22-Jul-2013 15:07:28 - [ 9] Visit: 04 Visit Requirements: SAME ORIENT AS 02 On Hold Comments: Additional Comments: In this visit, the ACS observations with F814W are carried out at two pointings. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 USS1558-003 ACS/WFC ACCUM WFCENTER F814W 1 1250 S PATTERN 2 1 -POS4 (5000 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ USS1558-003-POS4 1 ACS/WFC ACCUM WFCENTER F814W 1 none none none 1 N/A USS1558-003-POS4 1 ACS/WFC ACCUM WFCENTER F814W 2 none none none 1 N/A USS1558-003-POS4 1 ACS/WFC ACCUM WFCENTER F814W 3 none none none 2 N/A USS1558-003-POS4 1 ACS/WFC ACCUM WFCENTER F814W 4 none none none 2 N/A 13291( 3) - 22-Jul-2013 15:07:28 - [ 10] Visit: 05 Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: In this visit, the WFC3 observations with F160W are carried out at three pointings. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 USS1558-003 WFC3/IR MULTIAC IR-FIX F160W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 3 1 -POS1 CUM (5223.505 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 1 1 none none 1 N/A CUM USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 1 2 none none 1 N/A CUM USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 1 3 none none 1 N/A CUM USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 1 4 none none 1 N/A CUM USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 2 1 none none 2 N/A CUM USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 2 2 none none 2 N/A CUM USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 2 3 none none 2 N/A CUM USS1558-003-POS1 1 WFC3/IR MULTIAC IR-FIX F160W 2 4 none none 2 N/A CUM 13291( 3) - 22-Jul-2013 15:07:28 - [ 11] Summary Form for Proposal 13291 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR-FIX, WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=14, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 0D TO 0 D, ORIENT 135D TO 135 D, ORIENT 180D TO 180 D, ORIENT 270D TO 270 D, ORIENT 315D TO 315 D, ORIENT 90D TO 90 D, PATTERN 2 1, PATTERN 3 1, SAME ORIENT AS 01, SAME ORIENT AS 02 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names USS1558-003-POS1, USS1558-003-POS2, USS1558-003-POS3, USS1558-003-POS4, USS1558-003-POS5 ------------------------------------------------------------------------------------------------------------------------------------