11554( 5) - 19-Jun-2009 12:30:27 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11554 Version: 5 Check-in Time: 19-Jun-2009 12:30:27 STScI Edit Number: 2 Title Luminosity Profiles of Extremely Massive Clusters in NGC 7252 ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Nate John Bastian University of Cambridge CoI: Dr. Francois Schweizer Carnegie Institution of Washington N CoI: Dr. Soeren S. Larsen Universiteit Utrecht, Sterrekundig N Instituut CoI: Dr. Markus Kissler-Patig European Southern Observatory - Germany N ------------------------------------------------------------------------------------ Abstract The galactic merger remnant NGC 7252 represents one of the most extreme post-starburst environments in the local universe. During the disk-disk merger (~400 Myr ago) this galaxy produced the largest young massive star cluster population known, including two clusters above 10^7 Msun, a factor of 100 more massive than typical globular clusters in the Milky Way. We propose ACS-HRC observations of 3 fields in NGC 7252 in order to explore the detailed properties, i.e. luminosity profiles, of these massive star clusters. These observations will be able to test massive cluster formation mechanisms (e.g. the cluster merger scenario) as well as the possible tidal erosion and truncation of the outer regions of the clusters by the galactic tidal field. These observations will compliment our large on-going study using archival HST data, of star cluster profiles outside the Local Group. The cluster population in NGC 7252 will extend our sample in cluster mass by an order of magnitude. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose ACS-HRC observations of 3 fields in NGC 7252 in order to explore the detailed properties, i.e. luminosity profiles, of these massive star clusters. Three fields will be observed, each in the F475W and F775W filters. The multiple filters will allow independent checks of the size/profile, and allow us to gain some colour information for a large number of clusters. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11554( 5) - 19-Jun-2009 12:30:27 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC7252-2 STELLAR CLUSTER, RA=22H20M44.9980S +/- 0.1", J2000 V = 20 +/- 3 GLOBULAR CLUSTER, DEC=-24D40'26.50" +/- 0.1" NUCLEUS, OPEN CLUSTER, STAR FORMING REGION Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 11554( 5) - 19-Jun-2009 12:30:27 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 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 ------------------------------------------------------------------------------------------------------------------------------------ 11554( 5) - 19-Jun-2009 12:30:27 - [ 4] Visit: 01 Visit Requirements: ORIENT 300D TO 330 D On Hold Comments: Additional Comments: In this visit we plan to have 6 subexposures, two short (60s) at the beginning and end (one at the start and one at the end) of the orbit (offset by 4.5 pixels, i.e. 0.18"). The main part of the orbit will consist of 4 * 500s subexposures, which will be dithered (small box 4 point dither) to improve PSF sampling. We prefer that the observations be taken a Orient=315. If the range of 'Orient' is insufficient for schedualing, then we can also use Orient=135 +- 15, but if this is the case we would like to re-center the observations by ~20" (please contact us if this is the case). We also prefer that Visit 02 be taken at the same orient as Visit 01. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC7252-2 WFC3/UVI ACCUM UVIS-FIX F475W CR-SPLIT=NO 1 60 S S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC7252-2 WFC3/UVI ACCUM UVIS-FIX F475W CR-SPLIT=NO 1 500 S GS ACQ SCENARIO BASE1B3; S PATTERN 2 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC7252-2 WFC3/UVI ACCUM UVIS-FIX F475W CR-SPLIT=NO 1 60 S POS TARG 0.18, 0.0 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC7252-2 1 WFC3/UVI ACCUM UVIS-FIX F475W none none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F475W 1 none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F475W 2 none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F475W 3 none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F475W 4 none none none 1 N/A S NGC7252-2 3 WFC3/UVI ACCUM UVIS-FIX F475W none none none none 1 N/A S 11554( 5) - 19-Jun-2009 12:30:27 - [ 5] Visit: 02 Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: This 2nd visit, should be exactly the same as Visit 01, except images will be taken with the F775W filter instead of the F475W. Please see the comments in Visit 01 as to the goal and preferences of this observation. We prefer that Visit 02 be taken at the same orient as Visit 01. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC7252-2 WFC3/UVI ACCUM UVIS-FIX F775W CR-SPLIT=NO 1 60 S S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC7252-2 WFC3/UVI ACCUM UVIS-FIX F775W CR-SPLIT=NO 1 500 S GS ACQ SCENARIO BASE1B3; S PATTERN 2 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC7252-2 WFC3/UVI ACCUM UVIS-FIX F775W CR-SPLIT=NO 1 60 S POS TARG 0.18, null 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC7252-2 1 WFC3/UVI ACCUM UVIS-FIX F775W none none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F775W 1 none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F775W 2 none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F775W 3 none none none 1 N/A S NGC7252-2 2 WFC3/UVI ACCUM UVIS-FIX F775W 4 none none none 1 N/A S NGC7252-2 3 WFC3/UVI ACCUM UVIS-FIX F775W none none none none 1 N/A S 11554( 5) - 19-Jun-2009 12:30:27 - [ 6] Summary Form for Proposal 11554 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, ORIENT 300D TO 330 D, PATTERN 2 2, POS TARG 0.18, 0.0, POS TARG 0.18, null, SAME ORIENT AS 01 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W, F775W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC7252-2 ------------------------------------------------------------------------------------------------------------------------------------