6596( 5) - 12/09/98 14:57 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6596 Version: 5 Check-in Date: 15-Jul-1997 10:43:34 1.Proposal Title: Formation of Stellar Systems in Mergers in a Compact Group of Galaxies ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 6 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Jane Charlton Pennsylvania State University CoI: Dennis Zaritsky University of California/Lick N Observatories CoI: Sally Hunsberger Pennsylvania State University N ------------------------------------------------------------------------------------ 5. Abstract We propose to study a mechanism of galaxy formation at the present epoch by obtaining WFPC2 images in three filters (F450W, F569W, and F814W) of two fields within the compact group of galaxies, HCG92 (Hickson Compact Group 92, also known as Stephan's quintet). These fields encompass three interacting galaxies and their associated tidal features. Two different types of stellar systems may form as a consequence of mergers: globular clusters around the centers of merger products, and dwarf galaxies in the associated tidal debris. In R-band images, obtained at the Palomar 1.5m, we have identified 27 candidate dwarf galaxies in the tidal features in HCG92. HST WFPC2 images are needed to determine the nature of these objects by measuring surface brightness profiles and by resolving substructure and detailed morphology in different colors. In the two fields, the Planetary Camera will be positioned on a galaxy nucleus and on a portion of the tidal debris. The proposed exposures will allow resolution of forming globular clusters with the same properties as those observed with HST in several other merger remnants. This detailed study will enable an evaluation of how environmental conditions influence the nature of the stellar systems to be formed and an assessment of the contribution of tidal dwarf formation to the overall population of dwarf galaxies. ------------------------------------------------------------------------------------ 6596( 5) - 12/09/98 14:57 - [ 2] Observations Description ------------------------ The WFPC2 will be used with the F450W, F569W, and F814W filters to image two fields in Hickson Compact Group 92. In one field the PC will be centered on tidal debris in the merger remnant NGC7319 and the WFC will include a tidal tail containing 13 dwarf galaxy candidates. In the second field the PC will be centered on the nucleus of NGC7319 and four tidal features of the interacting pair NGC7318A/B are included in the WFC region. Exposure times in F450W, F569W, and F814W will be 112, 53, and 33 minutes, respectively. Based on results from our ground based images, these times are estimated to yield S/N = 13, 16, and 20 for the mean surface brightness of tidal dwarf candidates at a limiting value of 24.6 magnitudes per square arcsecond in V. The surface brightness profile will sample 16 pixels along the radius of a typical dwarf candidate. In the same exposures a pixel in the PC corresponds to 26h^{-1}pc, comparable to the effective radius of the young globular clusters in the Antennae system (Whitmore and Schweizer 1995). A S/N of approximately 10 is obtained for a globular cluster with M_V=-7, similar to the magnitude limit expected in Cycle 5 observations of the Antennae (Whitmore 1995 ID #5962). Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: Media: 8MM Blocking Factor: 10 Ship To: PI_Address, Jane C. Charlton, Astronomy & Astrophysics Department, 525 Davey Lab, University Park, PA 16802 Ship Via: Email: ------------------------------------------------------------------------------------ 6596( 5) - 12/09/98 14:57 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC7319 GALAXY, TIDAL TAIL RA=22H 36M 5.92S +/- 2S, DEC=33D J2000 Z=0.0215 V = 13.1 57' 47.39" +/- 2", PLATE-ID=02TP 2 NGC7318 GALAXY, TIDAL TAIL, RA=22H 36M 3.92S +/- 2S, DEC=33D J2000 Z=0.0215 V = 13.0 INTERACTING GALAXY 58' 34.38" +/- 2", PLATE-ID=02TP 6596( 5) - 12/09/98 14:57 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 237D TO 237D On Hold Comments: Additional Comments: Orientation could possibly be adjusted if essential for scheduling, however this value is highly preferred to fit all targets within the field and to ideally position the PC. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC7319 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1600 S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC7319 WFPC2 IMAGE PC1-FIX F569W 5624 CR-SPLIT=NO 2 800 S ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC7319 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1700 S ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC7319 WFPC2 IMAGE PC1-FIX F814W 7940 CR-SPLIT=NO 2 500 S ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC7319 WFPC2 IMAGE PC1-FIX F814W 7940 CR-SPLIT=NO 2 500 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC7319 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1700 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC7319 WFPC2 IMAGE PC1-FIX F569W 5624 CR-SPLIT=NO 2 800 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC7319 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1700 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 6596( 5) - 12/09/98 14:57 - [ 5] Visit: 02 Visit Priority: Visit Requirements: ORIENT 57D TO 57D On Hold Comments: Additional Comments: Orientation could possibly be adjusted if essential for scheduling, however this value is highly preferred to fit all targets within the field and to ideally position the PC. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC7318 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1600 S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC7318 WFPC2 IMAGE PC1-FIX F569W 5624 CR-SPLIT=NO 2 800 S ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC7318 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1700 S ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC7318 WFPC2 IMAGE PC1-FIX F814W 7940 CR-SPLIT=NO 2 500 S ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC7318 WFPC2 IMAGE PC1-FIX F814W 7940 CR-SPLIT=NO 2 500 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC7318 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1700 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC7318 WFPC2 IMAGE PC1-FIX F569W 5624 CR-SPLIT=NO 2 800 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC7318 WFPC2 IMAGE PC1-FIX F450W 4519 CR-SPLIT=NO 1 1700 S POS TARG 0.25, 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 6596( 5) - 12/09/98 14:57 - [ 6] Summary Form for Proposal 6596 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 237D TO 237D POS TARG 0.25, 0.25 ORIENT 57D TO 57D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F450W F569W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC7319 NGC7318 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4519 5624 7940 ------------------------------------------------------------------------------------------------------------------------------------