11182( 3) - 05/14/07 09:20 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11182 Version: 3 Check-in Time: 14-May-2007 13:20:18 STScI Edit Number: 1 Title The Mass of the Milky Way: Orbits for Leo I and Leo II: Second Epoch Imaging of Leo II ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 16 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Konrad Kuijken Universiteit Leiden CoI: Dr. R. Michael Rich University of California - Los Angeles N CoI: Dr. Jay Anderson Rice University N CoI: Dr. Andreas koch University of California - Los Angeles N CoI: Mr. Mario soto vicencio Universiteit Leiden N ------------------------------------------------------------------------------------ Abstract Constraining the mass of the Galaxy at large radii remains a difficult problem. Available data are still rather scarce, and orbits of even a few objects at large radii can have a large impact. We propose to obtain proper motions for the two satellites Leo I and Leo II, which orbit the Galaxy at about 200 kpc. Together with the radial velcoities of these glaaxies, which are well known, the proper motions allow space velocities ot be consructed: these can remove signifiicant uncertainty in the Galactic mass models, and in particular settle the vexed question of whether or not Leo I is gravitationally bound to the Galaxy. The proper motion of Leo I is addressed in a companion archival proposal; here we address the WFPC2 imagery of Leo II. ------------------------------------------------------------------------------------ Observations Description ------------------------ The aim of this proposal is second epoch imaging of the Leo II dwarf spheroidal galaxy, with the aim of measuring the proper motion and ultimately, constraining an orbit for the distant dwarf spheroidal galaxy. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11182( 3) - 05/14/07 09:20 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LEO-II GALAXY, DWARF RA=11H13M30.4400S +/- 0.1", J2000 V = 22.0+/-0.2 SPHEROIDAL DEC=+22D09'30.00" +/- 0.1" Reference Frame: ICRS 11182( 3) - 05/14/07 09:20 - [ 3] Visit: 01 Visit Priority: Visit Requirements: ORIENT 139.15D TO 139.25 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 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG -0.2,-0.2; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 2 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG -0.35,-0.8625 ------------------------------------------------------------------------------------------------------------------------------------ 3 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG 1.0125,-0.75; NEW OBSET FULL ACQ; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 4 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG 0.5625, 0.0875 ------------------------------------------------------------------------------------------------------------------------------------ 5 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG -0.875,-0.1875; NEW OBSET FULL ACQ; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 6 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG 0.075, 0.325 ------------------------------------------------------------------------------------------------------------------------------------ 7 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG -0.4625, 0.6625; NEW OBSET FULL ACQ; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 8 LEO-II WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S POS TARG 0.3875, 0.975 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEO-II 1 WFPC2 IMAGE PC1 F555W none none none none 1 N/A LEO-II 2 WFPC2 IMAGE PC1 F555W none none none none 1 N/A LEO-II 3 WFPC2 IMAGE PC1 F555W none none none none 2 N/A LEO-II 4 WFPC2 IMAGE PC1 F555W none none none none 2 N/A LEO-II 5 WFPC2 IMAGE PC1 F555W none none none none 3 N/A LEO-II 6 WFPC2 IMAGE PC1 F555W none none none none 3 N/A LEO-II 7 WFPC2 IMAGE PC1 F555W none none none none 4 N/A LEO-II 8 WFPC2 IMAGE PC1 F555W none none none none 4 N/A 11182( 3) - 05/14/07 09:20 - [ 4] Visit: 02 Visit Priority: Visit Requirements: ORIENT 139.15D TO 139.25 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 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG -0.2,-0.2; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 2 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG -0.35,-0.8625 ------------------------------------------------------------------------------------------------------------------------------------ 3 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG 1.0125,-0.75; NEW OBSET FULL ACQ; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 4 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG 0.5625, 0.0875 ------------------------------------------------------------------------------------------------------------------------------------ 5 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG -0.875,-0.1875; NEW OBSET FULL ACQ; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 6 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG 0.075, 0.325 ------------------------------------------------------------------------------------------------------------------------------------ 7 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG -0.4625, 0.6625; NEW OBSET FULL ACQ; GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 8 LEO-II WFPC2 IMAGE PC1 F814W CR-SPLIT=NO 1 1100 S POS TARG 0.3875, 0.975 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ LEO-II 1 WFPC2 IMAGE PC1 F814W none none none none 1 N/A LEO-II 2 WFPC2 IMAGE PC1 F814W none none none none 1 N/A LEO-II 3 WFPC2 IMAGE PC1 F814W none none none none 2 N/A LEO-II 4 WFPC2 IMAGE PC1 F814W none none none none 2 N/A LEO-II 5 WFPC2 IMAGE PC1 F814W none none none none 3 N/A LEO-II 6 WFPC2 IMAGE PC1 F814W none none none none 3 N/A LEO-II 7 WFPC2 IMAGE PC1 F814W none none none none 4 N/A LEO-II 8 WFPC2 IMAGE PC1 F814W none none none none 4 N/A 11182( 3) - 05/14/07 09:20 - [ 5] Summary Form for Proposal 11182 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 139.15D TO 139.25 D; POS TARG -0.2,-0.2; GS ACQ SCENARIO SINGLE; POS TARG -0.35,-0.8625; POS TARG 1.0125,-0.75; NEW OBSET FULL ACQ; POS TARG 0.5625, 0.0875; POS TARG -0.875,-0.1875; POS TARG 0.075, 0.325; POS TARG -0.4625, 0.6625; POS TARG 0.3875, 0.975; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names LEO-II ------------------------------------------------------------------------------------------------------------------------------------