6835( 4) - 02/12/96 09:52 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6835 Version: 4 Check-in Date: 12-Feb-1996 09:46:43 1.Proposal Title: The Detailed Morphology of Post-Merger Galaxies ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COSMOLOGY GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Ann Zabludoff Carnegie Observatories CoI: Dennis Zaritsky Lick Observatory/University of California, N Santa Cruz CoI: Christopher Mihos Johns Hopkins University N ------------------------------------------------------------------------------------ 6. Abstract From the Las Campanas Redshift Survey, the largest existing spectroscopic galaxy survey, we have drawn a unique and well- defined sample of 21 galaxies with the spectral and morphological signatures of evolved merger products. These galaxies have spectra indicating little or no on-going star formation and a significant young stellar population. Morphologically, the galaxies are disturbed, with tidal tails on scales of ~10 kpc. Because the observed tidal features survive at least ~ 1 Gyr after the merger, we are unable to use them to tightly constrain the time elapsed since the end of the starburst. This timescale is the key to determining (1) the duration and frequency of the post- starburst phase in the evolution of galaxies and (2) the fraction of the stellar mass created in the starburst. We propose to use the high spatial resolution of WFPC2 to detect the small-scale (< 1 kpc) features in five post-starburst galaxies that will enable us to measure the time since the merger to within a few 100 Myr. ------------------------------------------------------------------------------------ 6835( 4) - 02/12/96 09:52 - [ 2] Observations Description ------------------------ We propose to obtain WFPC2 observations through two filters (F439W and F702W) of the detailed morphology of post- starburst galaxies for which we have extensive ground-based imaging and spectroscopy. We require imaging in these two filters to identify the young stellar component, specifically its distribution near the nucleus and in the tidal tails where simulations predict it will accumulate after the merger. The angular size of the largest of the small-scale features described in the scientific justification corresponds to ~ 20 PC pixels for the typical redshift of our targets, z = 0.08. To conservatively estimate the significance of our detection of features at least this small in one orbit, we calculate the signal-to-noise (cf. WFPC2 Instrument Handbook) in a 2 * 2 sq PC pixel aperture for a young star cluster like those observed in NGC 1275 as point sources with the PC (M_V ~ -13; Holtzman Etal 1992). In a CR -split 30 minute exposure, we obtain a ~ 25Sigma detection in F439W and a ~ 85Sigma detection in F702W. We expect the galaxies' nuclei, non- axisymmetric features, and small scale zones of recent star formation to be at least as luminous. The ``wide'' R filter is requested, because (1) we have ground-based Johnson B and R images for calibration of the proposed images, (2) the transmission efficiency of F702W is much better than the standard Johnson R filter, and (3) the means of the transmission ranges of F439W and F702W are well separated. Because all of our targets have |b^II| > 50^degrees, galactic reddening is not a problem. Two filters are necessary since many of the non- axisymmetric features should also have distinguishing colors. At the typical redshifts of our targets, the PC field corresponds to ~ 30 kpc, enough to easily sample the features of interest within the central few kpc. From our ground-based images we know the orientation any tidal tails, which extend beyond ~ 10 kpc. We will request that the telescope be oriented so that these tidal tails, or any dwarf irregular galaxies (such as those coalescing from the tidal tails of the Antennae merging system; Mirabel, Dottori, & Lutz 1992) or globular clusters formed in these structures, are detectable with the WFC. There are no bright stars in the target fields. Real Time Justification ----------------------- None. None. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6835( 4) - 02/12/96 09:52 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-0217- GALAXY RA = 02H 15M 43.24S +/- 0.1S, B1950 V=+29600 V = 17.7+/-0.5 4432 DEC = -44D 46' 36.7" +/- 1.0" Comments: E+A Galaxy 2 GAL-0400- GALAXY RA = 03H 58M 23.42S +/- 0.1S, B1950 V=+30350 V = 17.0+/-0.5 4435 DEC = -44D 43' 40.3" +/- 1.0" Comments: E+A Galaxy 3 GAL-1101- GALAXY RA = 10H 58M 48.98S +/- 0.1S, B1950 V=+22380 V = 18.4+/-0.5 1210 DEC = -11D 54' 09.8" +/- 1.0" Comments: E+A Galaxy 4 GAL-0158- GALAXY RA = 01H 56M 00.12S +/- 0.1S, B1950 V=+35170 V = 18.1+/-0.5 4437 DEC = -44D 51' 49.0" +/- 1.0" Comments: E+A Galaxy 5 GAL-1209- GALAXY RA = 12H 06M 31.34S +/- 0.1S, B1950 V=+24310 V = 16.4+/-0.5 1222 DEC = -12D 05' 55.4" +/- 1.0" Comments: E+A Galaxy 6835( 4) - 02/12/96 09:52 - [ 4] Visit: 01 Visit Requirements: ORIENTation 0D TO 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-0217- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 3 700S 4432 ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-0217- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 1 60S 4432 ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-0217- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 700S 4432 ------------------------------------------------------------------------------------------------------------------------------------ 4 GAL-0217- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 60S 4432 ------------------------------------------------------------------------------------------------------------------------------------ 6835( 4) - 02/12/96 09:52 - [ 5] Visit: 02 Visit Requirements: ORIENTation 225D TO 315D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 5 GAL-0400- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 3 700S 4435 ------------------------------------------------------------------------------------------------------------------------------------ 6 GAL-0400- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 1 60S 4435 ------------------------------------------------------------------------------------------------------------------------------------ 7 GAL-0400- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 700S 4435 ------------------------------------------------------------------------------------------------------------------------------------ 8 GAL-0400- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 60S 4435 ------------------------------------------------------------------------------------------------------------------------------------ 6835( 4) - 02/12/96 09:52 - [ 6] Visit: 03 Visit Requirements: ORIENTation 45D TO 55D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 9 GAL-1101- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 3 700S 1210 ------------------------------------------------------------------------------------------------------------------------------------ 10 GAL-1101- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 1 60S 1210 ------------------------------------------------------------------------------------------------------------------------------------ 11 GAL-1101- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 700S 1210 ------------------------------------------------------------------------------------------------------------------------------------ 12 GAL-1101- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 60S 1210 ------------------------------------------------------------------------------------------------------------------------------------ 6835( 4) - 02/12/96 09:52 - [ 7] Visit: 04 Visit Requirements: ORIENTation 135D TO 225D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 13 GAL-0158- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 3 700S 4437 ------------------------------------------------------------------------------------------------------------------------------------ 14 GAL-0158- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 1 60S 4437 ------------------------------------------------------------------------------------------------------------------------------------ 15 GAL-0158- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 700S 4437 ------------------------------------------------------------------------------------------------------------------------------------ 16 GAL-0158- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 60S 4437 ------------------------------------------------------------------------------------------------------------------------------------ 6835( 4) - 02/12/96 09:52 - [ 8] Visit: 05 Visit Requirements: ORIENTation 90D TO 135D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 17 GAL-1209- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 3 700S 1222 ------------------------------------------------------------------------------------------------------------------------------------ 18 GAL-1209- WFPC2 IMAGE PC1-FIX F439W CR-SPLIT=NO 1 60S 1222 ------------------------------------------------------------------------------------------------------------------------------------ 19 GAL-1209- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 700S 1222 ------------------------------------------------------------------------------------------------------------------------------------ 20 GAL-1209- WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 60S 1222 ------------------------------------------------------------------------------------------------------------------------------------ 6835( 4) - 02/12/96 09:52 - [ 9] Summary Form for Proposal 6835 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENTation 0D TO 90D ORIENTation 225D TO 315D ORIENTation 45D TO 55D ORIENTation 135D TO 225D ORIENTation 90D TO 135D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F439W F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GAL-0217-4432 GAL-0400-4435 GAL-1101-1210 GAL-0158-4437 GAL-1209-1222 ------------------------------------------------------------------------------------------------------------------------------------