13370( 2) - 17-Jun-2013 11:32:33 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13370 Version: 2 Check-in Time: 17-Jun-2013 11:32:33 STScI Edit Number: 0 Title The Formation History of UGC 12591 - the Most Massive Known Field S0 Galaxy ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Iskren Y. Georgiev European Space Agency - ESTEC Y CoI: Dr. Paul Goudfrooij Space Telescope Science Institute N CoI: Dr. Thomas H. Puzia Pontificia Universidad Catolica de Chile N ------------------------------------------------------------------------------------ Abstract We propose to determine the formation history of UGC12591 - the most massive known field S0 galaxy in the nearby Universe (D ~ 98Mpc). Its maximum rotational velocity of 483 km/s yields a dynamical mass within 50 kpc of 2x10^12 solar masses. Given its field location, this poses the question of how such a massive bulge can grow in isolation? To trace the UGC12591 star formation and assembly history we will use the properties of its globular clusters (GCs) and massive compact stellar systems which are expected in huge numbers given its mass. In particular, GCs are well known to be among the best indicators of major (merger) galaxy formation episodes, capturing the physical conditions at the time of their formation. With the wide spectral coverage of the proposed obesrvations, we will 1) search for multiple/intermediate-age GC populations and 2) measure whether the specific frequency of the metal-rich GCs relative to the bulge luminosity is enhanced. If any of these points are confirmed, this would strongly favor a merger-driven (gas-rich) as opposed to "passive" bulge growth (secular evolution). The only possible way to derive robust photometric GC ages and metallicities at the distance of UGC12591 in a reasonable amount of time is by employing the efficiency of HST/WFC3 and the age-metallicity sensitive V, I, H filter combination (F606W, F814W, F160W). In four orbits we will observe the brighter half of the GC population of UGC12591, which will enable us to derive GC population peak age and metallicity (+/- 20%). The results from this proposal will offer an important leap forward in our understanding of the assembly history of extremely massive isolated S0 galaxies. ------------------------------------------------------------------------------------ Observations Description ------------------------ Observations will be performed with the UVIS & IR F606W, F814W, F160W filter set (i.e. V, I, H) to allow a robust GC age and metallicity derivation. Exposure times are estimated based on the STScI ETC and a custom made script to account for the local background surface brightness. To reach V<27.5mag with S/N>5, a BC03 G2V spectrum, E(B-V)=0.114mag, an "elliptical galaxy" background surface brightness of mu_V = 21 mag/arcsec^2 (typical for a few arcsec from the galaxy center), and zodiacal light calculated from the UGC 12591 position, we obtain the following exposure times: 2500, 3000 and 5700 seconds in WFC3/UVIS F606W, F814W , and IR F160W, respectively. Three-point dither-line pattern for the F606W and F814W and four-point for F160W will allow a good sampling of the PSF, and facilitate cosmic-ray and detectors artifacts removal. With the APT Phase II orbit planner optimization, and accounting for overheads, we were able 13370( 2) - 17-Jun-2013 11:32:33 - [ 2] to accommodate the following exposure time splits: 3x873 = 2619 and 3x913 = 2739 seconds for F606W and F814W, and 4x1400 seconds (NSAMP = 14, STEP200) in F160W. We note that beyond the central mu_V = 21 mag/arcsec^2 the S/N will be higher, i.e. at radius where the majority of the GCs are located in a galaxy. UGC 12591 is perfectly covered by one WFC3 pointing to about 2x of its D25 = 1.23' (RC3). The position and min and maxorient (230-265 degrees) were chosen such that the galaxy is entirely covered by one of the WFC3/UVIS detectors as well as the nearby satellite galaxy in the other. For proper analysis of the UGC 12591 evolution history, it is important to keep the observations within the specified position and orientation. To estimate background contamination from unresolved distant galaxies and foreground Galactic stars, we will use in coordinated parallel the ACS/WFC camera in F606W and F814W filters. The high spatial resolution of both WFC3 (0.04"/pix) and ACS (0.05"/pix) will already allow to significantly reduce the number of background contamination, unachievable with ground-based observations. Their exposure time splits have been adjusted such that the total integration time for each filter reaches S/N~10 at V=27.5mag. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 13370( 2) - 17-Jun-2013 11:32:33 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 UGC-1259-UVI GALAXY, ELLIPTICAL, RA=23H25M27.0342S +/- 0.1", J2000 V = 13.4 S LENTICULAR DEC=+28D29'25.56" +/- 0.1" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 2 UGC-1259-IR GALAXY, ELLIPTICAL, RA=23H25M23.4749S +/- 0.1", J2000 V = 13.0 LENTICULAR DEC=+28D29'52.11" +/- 0.1" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 13370( 2) - 17-Jun-2013 11:32:33 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.636 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 13370( 2) - 17-Jun-2013 11:32:33 - [ 5] Visit: 01 Visit Requirements: ORIENT 230D TO 265 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 UGC-1259-UV WFC3/UVI ACCUM UVIS1 F606W CR-SPLIT=NO, BIN=NONE 1 1600 S POS TARG IS S see below -0.6944182534020316, (2619 S) -11.059692956474212; PATTERN 1 1-2; PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 UGC-1259-UV ACS/WFC ACCUM WFC F606W CR-SPLIT=NO, GAIN=2.0 1 1100 S IS see below (2384 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 UGC-1259-UV WFC3/UVI ACCUM UVIS1 F814W CR-SPLIT=NO, BIN=NONE 1 3100 S PATTERN 1 3-4; PAR 4 IS S see below WITH 3 (2739 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 UGC-1259-UV ACS/WFC ACCUM WFC F814W CR-SPLIT=NO, GAIN=2.0 1 2100 S IS see below (2482 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 UGC-1259-IR WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=STEP200 1 DEF PATTERN 2 5-7; PAR 6-7 CUM (5596.926 WITH 5 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 UGC-1259-IR ACS/WFC ACCUM WFC F606W CR-SPLIT=NO, GAIN=2.0 1 400 S see below (1735 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 UGC-1259-IR ACS/WFC ACCUM WFC F814W CR-SPLIT=NO, GAIN=2.0 1 670 S (2680 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 | ------------------------------------------------------------------------------------------------------------------------------------ UGC-1259-UVIS 1 WFC3/UVI ACCUM UVIS1 F606W 1 none none none 1 873.0 S S UGC-1259-UVIS 1 WFC3/UVI ACCUM UVIS1 F606W 2 none none none 1 873.0 S S UGC-1259-UVIS 1 WFC3/UVI ACCUM UVIS1 F606W 3 none none none 1 873.0 S S UGC-1259-UVIS 2 ACS/WFC ACCUM WFC F606W 1 none none none 1 793.0 S 13370( 2) - 17-Jun-2013 11:32:33 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ UGC-1259-UVIS 2 ACS/WFC ACCUM WFC F606W 2 none none none 1 843.0 S UGC-1259-UVIS 2 ACS/WFC ACCUM WFC F606W 3 none none none 1 748.0 S UGC-1259-UVIS 3 WFC3/UVI ACCUM UVIS1 F814W 1 none none none 2 913.0 S S UGC-1259-UVIS 3 WFC3/UVI ACCUM UVIS1 F814W 2 none none none 2 913.0 S S UGC-1259-UVIS 3 WFC3/UVI ACCUM UVIS1 F814W 3 none none none 2 913.0 S S UGC-1259-UVIS 4 ACS/WFC ACCUM WFC F814W 1 none none none 2 852.0 S UGC-1259-UVIS 4 ACS/WFC ACCUM WFC F814W 2 none none none 2 852.0 S UGC-1259-UVIS 4 ACS/WFC ACCUM WFC F814W 3 none none none 2 778.0 S UGC-1259-IR 5 WFC3/IR MULTIAC IR F160W 1 none none none 3 N/A CUM UGC-1259-IR 5 WFC3/IR MULTIAC IR F160W 2 none none none 3 N/A CUM UGC-1259-IR 5 WFC3/IR MULTIAC IR F160W 3 none none none 4 N/A CUM UGC-1259-IR 5 WFC3/IR MULTIAC IR F160W 4 none none none 4 N/A CUM UGC-1259-IR 6 ACS/WFC ACCUM WFC F606W 1 none none none 3 336.0 S UGC-1259-IR 6 ACS/WFC ACCUM WFC F606W 2 none none none 3 500.0 S UGC-1259-IR 6 ACS/WFC ACCUM WFC F606W 3 none none none 4 399.0 S UGC-1259-IR 6 ACS/WFC ACCUM WFC F606W 4 none none none 4 500.0 S UGC-1259-IR 7 ACS/WFC ACCUM WFC F814W 1 none none none 3 N/A UGC-1259-IR 7 ACS/WFC ACCUM WFC F814W 2 none none none 3 N/A UGC-1259-IR 7 ACS/WFC ACCUM WFC F814W 3 none none none 4 N/A UGC-1259-IR 7 ACS/WFC ACCUM WFC F814W 4 none none none 4 N/A 13370( 2) - 17-Jun-2013 11:32:33 - [ 7] Summary Form for Proposal 13370 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS1, WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BIN=NONE, CR-SPLIT=NO, GAIN=2.0, NSAMP=14, SAMP-SEQ=STEP200 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 230D TO 265 D, PAR 2 WITH 1, PAR 4 WITH 3, PAR 6-7 WITH 5, PATTERN 1 1-2, PATTERN 1 3-4, PATTERN 2 5-7, POS TARG -0.6944182534020316, -11.059692956474212 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names UGC-1259-IR, UGC-1259-UVIS ------------------------------------------------------------------------------------------------------------------------------------