! Proposal 5962, submission 2 ! PI: Brad Whitmore ! Received Tue Mar 19 12:25:27 EST 1996 ! From: whitmore@stsci.edu ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5962,v 10.1 1996/04/08 15:26:48 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Debra Wallace ! Phone: 410 338-4506 , E-mail: wallace@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Sat Dec 17 11:32:08 EST 1994 ! Proposal_Information ! Section 4 Title: Young Globular Clusters in Merging Galaxies: Part 3 Proposal_Category: GO Scientific_Category: Galaxies & Clusters Cycle: 5 Investigators PI_name: Brad Whitmore PI_Institution: Space Telescope Science Institute CoI_Name: Francois Schweizer CoI_Institution: Carnegie Inst. of Washington - DTM Contact: ! Y or N (designate at most one contact) CoI_Name: Michael Fall CoI_Institution: Space Telescope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Claus Leitherer CoI_Institution: Space Telescope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Bryan Miller CoI_Institution: DTM/STScI Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) Cycle 2 HST observations by our team resulted in the discovery of 40 blue pointlike objects in NGC 7252 (Whitmore et al. 1993) and over 700 similar objects in NGC 4038/4039 (Whitmore & Schweizer 1994). These objects have the luminosities, colors, and radii of young globular clusters and must have formed during the mergers. Because of their proximity and early stage of merging, NGC 4038/4039 (``The Antennae'') is an ideal laboratory to study cluster formation in mergers. Here we propose to follow up the exploratory Cycle 2 observations with a solid combination of deep UBVI photometry, H Alpha imaging, and UV spectroscopy. Our primary goals are to (1) determine the luminosity function (LF) to 3.5 mag fainter than before to see whether it continues to rise like a power law or turns over and forms a Gaussian-like distribution similar to the classical LF of globular clusters, (2) age date the clusters (carefully correcting for reddening) and study their age distribution, and (3) determine the structural properties of the clusters (e.g., radius, central surface brightness, concentration, and ellipticity). These observations should allow us to better assess whether the ultraluminous star clusters observed in recent mergers may evolve to become typical globular clusters. The young clusters' small radii and principal emission in the UV require both the high resolution and improved UV capability of the repaired Space Telescope. Questions ! Free format text (please update) Observing_Description: For visit #1, the WFPC2 will be used with filters F336W (``U''; 2X 1000 s + 1100 s + 2 X 1200s), F439W (``B''; 4 X 1000 s, 2 X 60 s), F555W (``V''; 4 X 1100 s, 2 X 60 s), and F814W (``I''; 4 X 500 s, 2 X60 s) to observe the merging galaxies NGC 4038/4039. The short exposures are to guarantee unsaturated images of the brightest clusters. The exposures will be taken at 2 different positions separated by 0.25" in both X and Y. This corresponds to 5.5 PC pixels and 2.5 WF pixels. The subpixel dithering will allow us to obtain better spatial resolution from the undersampled images, while the total of 4 exposures will provide very good cosmic ray removal, and the offset will allow us to remove hot pixels. The position is centered on object # 345 from Whitmore et al., AJ, March 1995, based on WFPC1 observations. The orientation is arranged to fit both NGC 4038 and NGC 4039 into the WF. Visit #2 should be taken at the same orientation as visit 1, and within 30 days. This visit takes short images (2 X 30s in F555W) of a nearby star to aid in the analysis, using the same offsets as visit 1. An H-Alpha image of NGC 4038/4039 will also be taken (F658N; 2 X 900 s + 1000 s + 1100 s), with the normal dithering. The velocities range from 1450 to 1700 km s^-1, whence H-Alpha will be redshifted into the interval 6594--6600 Angstrom and will be nicely covered by the F658N filter (peak at 6592 Angstrom, range 6572--6610 Angstrom). A combination of the V and I images will be used to subtract the continuum. The S/N for a typical cluster in NGC 4038/4039 should be about 10, based on ground-based estimates of the H-Alpha flux (Keel et al. 1985, AJ, 90, 708; Amram et al. 1992, A&A, 266, 106), and a comparison with our Cycle 4 H-Alpha observations of NGC 4536. For visit # 3, the FOS/BL will be used with the G160L, and the GHRS will be used with the G140L grating and two different wavelength settings (1300 A and 1500 A) to obtain spectra of three of the brightest clusters in NGC 4038/4039. The FOS will be used for the acquisition, using a 2 stage peakup to center object 405 in the 1" aperture. It is possible that we will use an ACQ/BIN for the acquisition, depending on the results of the WFPC2 observations. After the FOS ACCUM observation, and an ACQ observation to obtain an image of the field we actually centered on, the telescope will be offset to the 2.0" aperture of the GHRS. The subsequent clusters will be acquired using a blind offset. WAVE observations are interspersed to determine accurate wavelength calibrations. At present, we plan to observe the clusters 405, 455, and 442. However, we may choose to change one or more of these if the H-Alpha images indicates that any of these are not very young clusters. Hence, visit 2 has been put ON HOLD, pending the H-Alpha observations in visit 2. NOTE ADDED March 18, 1996. The original visit 3 has now been split into 2 parts, visit 3 = FOS (acq) and GHRS observations of cluster 405 and 442, and visit 4 = FOC observations of regions T and G. Real_Time_Justification: Not applicable Not applicable. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: NGC4038 Alternate_Names: Description: Galaxy, Position: RA=12H 01M 50.421S +/- 0.01S, DEC=-18D 52' 17.84" +/- 0.01", ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 2000 RV_or_Z: V=1500 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=10 ! Include at least V and B-V Comments: Object # 345 from Whitmore et al. AJ, 000. All coordinates from WFPC1 observations. Fixed_Targets ! Section 5.1 Target_Number: 5 Target_Name: NGC4038-STAR6 Alternate_Names: Description: Star, Position: RA=12H 01M 51.606S +/- 0.01S, DEC=-18D 51' 34.68" +/- 0.01", ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 2000 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=16.7 ! Include at least V and B-V Comments: Star # 6 from Whitmore et al. AJ, 000. Fixed_Targets ! Section 5.1 Target_Number: 6 Target_Name: NGC4038-405-UPDATED Alternate_Names: Description: Ext-Cluster,Open Cluster,Emission Line Nebula Position: RA=12H 01M 50.421S +/- 0.05S, DEC=-18D 52' 11.468" +/- 0.5", PLATE-ID=04UV ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 2000 RV_or_Z: V=1500 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: F-Cont(5500)=1E-15 ! Include at least V and B-V Comments: Updated target based on early acquisition. Fixed_Targets ! Section 5.1 Target_Number: 7 Target_Name: NGC4038-442-UPDATED Alternate_Names: Description: Galaxy, Position: RA=12H 01M 52.973S +/- 0.05S, DEC=-18D 52' 8.37" +/- 0.5", PLATE-ID=04UV ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 2000 RV_or_Z: V=1500 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: F-Cont(5500)=1E-15 Comments: Updated target based on early acquisition. Fixed_Targets ! Section 5.1 Target_Number: 8 Target_Name: NGC4038-T Alternate_Names: Description: Star, Position: RA=12H 01M 50.437S +/- 0.01S, DEC=-18D 52' 19.23" +/- 0.01", PLATE-ID=04UV ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 2000 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=16.9 ! Include at least V and B-V Comments: Updated target based on early acquisition. Fixed_Targets ! Section 5.1 Target_Number: 9 Target_Name: NGC4038-G Alternate_Names: Description: Star, Position: RA=12H 01M 51.294S +/- 0.01S, DEC=-18D 51' 43.449" +/- 0.01", PLATE-ID=04UV ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 2000 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=17.3 ! Include at least V and B-V Comments: Updated target based on early acquisition. ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ORIENTation 275D TO 295D ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN