11711( 4) - 18-Feb-2010 14:34:14 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11711 Version: 4 Check-in Time: 18-Feb-2010 14:34:14 STScI Edit Number: 0 Title A Definitive Distance to the Coma Core Ellipticals ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. John P. Blakeslee Dominion Astrophysical Observatory CoI: Dr. Patrick Cote Dominion Astrophysical Observatory N CoI: Dr. Laura Ferrarese Dominion Astrophysical Observatory N CoI: Dr. Joseph Jensen Gemini Observatory, Northern Operations N CoI: Dr. Andres Jordan Smithsonian Institution Astrophysical N Observatory CoI: Dr. Simona Mei Observatoire de Paris N CoI: Dr. Eric W. Peng Space Telescope Science Institute N CoI: Dr. John L. Tonry University of Hawaii N ------------------------------------------------------------------------------------ Abstract As the richest galaxy cluster in the local universe (cz < 10, 000 km/s), the Coma cluster continues to serve as the standard of comparison for numerous studies of galaxy properties and scaling relations in clusters. The central importance of Coma has been recognized with two recent HST large programs: a Treasury survey to study the dwarf galaxy population by imaging 82 different ACS/WFC pointings, and a program to measure Cepheid distances to two spiral galaxies projected within the Coma core region. An accurate distance to the Coma core is essential for comparing the galaxy luminosities and sizes to nearby galaxies in Virgo and Fornax, while an accurate peculiar velocity is needed for correctly tying to more distant clusters. However, experience dictates that Cepheid distances to clusters must be carefully verified against accurate measurements to the dominant early-type population, especially for such an unprecedented effort as the Coma Cepheid search (the completion of which remains uncertain). We propose to measure highly accurate (3-4% internal error per galaxy) SBF distances to the two giant Coma core ellipticals. The reliability of the SBF method with the ACS/WFC has been repeatedly demonstrated, and it is so efficient that it requires only 3% of the number of orbits dedicated to the two current large Coma programs. The precise ACS SBF Coma core distance will also provide a good constraint on the Coma peculiar velocity, thus improving the accuracy of comparisons to distant clusters. Finally, our program will answer some longstanding puzzles surrounding the rich globular cluster population in the core of this archetypal galaxy cluster. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will target the two giant galaxies, NGC4874 and NGC4889, that define the core of the Coma cluster and measure their distances using the SBF method in the F814W bandpass of the ACS/WFC. S/N calculations show that we need at least four orbits in F814W to measure a reliable SBF signal. In addition, calibration of the SBF measurement to an absolute scale requires an accurate galaxy color. We will use F475W for the second bandpass, and thus calibrate the F814W SBF 11711( 4) - 18-Feb-2010 14:34:14 - [ 2] magnitude using F475W-F814W. To measure an accurate color for the SBF calibration requires one additional orbit with F475W, or five orbits in total per galaxy for the SBF observations. Another goal of our program is to obtain an accurate census of the globular cluster population and its color distribution. To obtain reasonably accurate colors at the peak of the GCLF requires at least 2 orbits of F475W integration, in addition to the deep F814W observations dictated by the SBF requirements. Thus, the total requirement to carry out our science program is four orbits in F814W and two orbits in F475W per galaxy. We can use one orbit's worth of archival ACS/WFC F475W data on NGC4874 for our purposes, reducing our total program to 11 orbits. We also have coordinated parallels with WFC3. For the NGC4889 observations (visits 2 and 3), we will place the WFC3/IR aperture on NGC4874 and image the latter galaxy in parallel in the F110W and F160W bandpasses. For the NGC4874 primary observations (visit 1), we will image a random parallel field with the F475X and F600LP bandpasses of WFC3/UVIS (it is not possible to image NGC4889 in parallel because the necessary orientation cannot be scheduled). Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11711( 4) - 18-Feb-2010 14:34:14 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-4874 GALAXY, ELLIPTICAL RA=12H59M36.1120S +/- 0.1", J2000 V = 11.6 +/- 0.3 DEC=+27D57'41.11" +/- 0.1" Reference Frame: Other: NED Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-4889 GALAXY, ELLIPTICAL RA=13H00M7.7954S +/- 0.1", J2000 V = 11.5 +/- 0.3 DEC=+27D58'36.96" +/- 0.1" Reference Frame: Other: NED Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 11711( 4) - 18-Feb-2010 14:34:14 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 1.5 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.28 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE LINE Pattern_Purpose DITHER DITHER Number_Of_Points 4 3 Point_Spacing 0.275 1.5 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 0.0 85.28 Angle_Between_Sides Center_Pattern NO NO Pattern_Comments: pattern & subpattern define a 4x3 grid of pointings. ------------------------------------------------------------------------------------------------------------------------------------ 11711( 4) - 18-Feb-2010 14:34:14 - [ 5] Visit: 01 Visit Requirements: ORIENT 143D TO 157 D; ORIENT 216D TO 248.0 D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-4874 ACS/WFC ACCUM WFCENTER F475W 1 60 S PATTERN 1 1-2; PAR 2 see below WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-4874 WFC3/UVI ACCUM UVIS F475X CR-SPLIT=NO 1 838 S S see below ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC-4874 ACS/WFC ACCUM WFCENTER F814W 1 60 S PATTERN 2 3-4; PAR 4 see below WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS F600LP CR-SPLIT=NO 1 700 S S see below ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4874 1 ACS/WFC ACCUM WFCENTER F475W 1 none none none 1 798.0 S NGC-4874 1 ACS/WFC ACCUM WFCENTER F475W 2 none none none 1 798.0 S NGC-4874 1 ACS/WFC ACCUM WFCENTER F475W 3 none none none 1 798.0 S NGC-4874 2 WFC3/UVI ACCUM UVIS F475X 1 none none none 1 879.0 S S NGC-4874 2 WFC3/UVI ACCUM UVIS F475X 2 none none none 1 829.0 S S NGC-4874 2 WFC3/UVI ACCUM UVIS F475X 3 none none none 1 829.0 S S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 1 1 none none 2 859.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 1 2 none none 2 859.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 1 3 none none 2 859.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 2 1 none none 3 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 2 2 none none 3 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 2 3 none none 3 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 3 1 none none 4 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 3 2 none none 4 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 3 3 none none 4 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 4 1 none none 5 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 4 2 none none 5 872.0 S NGC-4874 3 ACS/WFC ACCUM WFCENTER F814W 4 3 none none 5 872.0 S ANY 4 WFC3/UVI ACCUM UVIS F600LP 1 1 none none 2 890.0 S S 11711( 4) - 18-Feb-2010 14:34:14 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ ANY 4 WFC3/UVI ACCUM UVIS F600LP 1 2 none none 2 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 1 3 none none 2 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 2 1 none none 3 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 2 2 none none 3 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 2 3 none none 3 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 3 1 none none 4 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 3 2 none none 4 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 3 3 none none 4 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 4 1 none none 5 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 4 2 none none 5 890.0 S S ANY 4 WFC3/UVI ACCUM UVIS F600LP 4 3 none none 5 890.0 S S 11711( 4) - 18-Feb-2010 14:34:14 - [ 7] Visit: 02 Visit Requirements: ORIENT 216.2D TO 226.4 D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-4889 ACS/WFC ACCUM WFC2 F475W 1 795 S PATTERN 1 1-2; PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFC3/IR MULTIAC IR F110W NSAMP=14, SAMP-SEQ=STEP100 1 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC-4889 ACS/WFC ACCUM WFC2 F814W 1 830 S PATTERN 2 3-4; PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/IR MULTIAC IR F160W NSAMP=15, SAMP-SEQ=STEP100 1 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4889 1 ACS/WFC ACCUM WFC2 F475W 1 none none none 1 N/A NGC-4889 1 ACS/WFC ACCUM WFC2 F475W 2 none none none 1 N/A NGC-4889 1 ACS/WFC ACCUM WFC2 F475W 3 none none none 1 N/A ANY 2 WFC3/IR MULTIAC IR F110W 1 none none none 1 N/A CUM ANY 2 WFC3/IR MULTIAC IR F110W 2 none none none 1 N/A CUM ANY 2 WFC3/IR MULTIAC IR F110W 3 none none none 1 N/A CUM NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 1 1 none none 2 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 1 2 none none 2 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 1 3 none none 2 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 2 1 none none 3 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 2 2 none none 3 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 2 3 none none 3 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 3 1 none none 4 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 3 2 none none 4 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 3 3 none none 4 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 4 1 none none 5 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 4 2 none none 5 N/A NGC-4889 3 ACS/WFC ACCUM WFC2 F814W 4 3 none none 5 N/A ANY 4 WFC3/IR MULTIAC IR F160W 1 1 none none 2 N/A CUM 11711( 4) - 18-Feb-2010 14:34:14 - [ 8] 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 | ------------------------------------------------------------------------------------------------------------------------------------ ANY 4 WFC3/IR MULTIAC IR F160W 1 2 none none 2 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 1 3 none none 2 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 2 1 none none 3 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 2 2 none none 3 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 2 3 none none 3 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 3 1 none none 4 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 3 2 none none 4 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 3 3 none none 4 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 4 1 none none 5 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 4 2 none none 5 N/A CUM ANY 4 WFC3/IR MULTIAC IR F160W 4 3 none none 5 N/A CUM 11711( 4) - 18-Feb-2010 14:34:14 - [ 9] Visit: 03 Visit Requirements: SAME ORIENT AS 02 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-4889 ACS/WFC ACCUM WFC2 F475W 1 795 S PATTERN 1 1-2; PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFC3/IR MULTIAC IR F110W NSAMP=14, SAMP-SEQ=STEP100 1 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4889 1 ACS/WFC ACCUM WFC2 F475W 1 none none none 1 N/A NGC-4889 1 ACS/WFC ACCUM WFC2 F475W 2 none none none 1 N/A NGC-4889 1 ACS/WFC ACCUM WFC2 F475W 3 none none none 1 N/A ANY 2 WFC3/IR MULTIAC IR F110W 1 none none none 1 N/A CUM ANY 2 WFC3/IR MULTIAC IR F110W 2 none none none 1 N/A CUM ANY 2 WFC3/IR MULTIAC IR F110W 3 none none none 1 N/A CUM 11711( 4) - 18-Feb-2010 14:34:14 - [ 10] Summary Form for Proposal 11711 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS, WFC2, WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, NSAMP=14, NSAMP=15, SAMP-SEQ=STEP100 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 143D TO 157 D, ORIENT 216.2D TO 226.4 D, ORIENT 216D TO 248.0 D, PAR 2 WITH 1, PAR 4 WITH 3, PATTERN 1 1-2, PATTERN 2 3-4, SAME ORIENT AS 02 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F160W, F475W, F475X, F600LP, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ANY, NGC-4874, NGC-4889 ------------------------------------------------------------------------------------------------------------------------------------