6582( 4) - 01/04/99 14:58 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6582 Version: 4 Check-in Date: 04-Jan-1999 14:57:57 1.Proposal Title: Are the damped Lyman-Alpha systems at z>3 really spiral galaxies? ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 6 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Andrew Bunker University of California CoI: Dr. Stephen WARREN Astrophysics Group, Imperial College, N London, UK ------------------------------------------------------------------------------------ 5. Abstract We still do not know well the sizes of the damped Lyman-Alpha systems or their star formation rates. Here we propose to apply a new technique to image continuum emission from two damped Lyman-Alpha systems, z_abs=3.40 & 3.89, seen in the spectrum of the quasar PC 0953+4749 (z_em=4.46). Continuum emission from these absorbers, uncontaminated by light from the background quasar, is observable at wavelengths shorter than the Lyman limit of a third damped Lyman-Alpha system at z_ abs=4.25. Deep ground-based images are being used to identify the absorbers. The HST images will provide the morphologies of the damped systems. Recent theories suggest that galaxies at high redshift, z>3, are composed of a number of very compact sub- units, that merge at lower redshift. Existing deep HST images in two fields lend support to this view. The imaging proposed here will provide an additional test of this picture, and will clarify the role the damped systems play in the formation of galaxies. ------------------------------------------------------------------------------------ 6582( 4) - 01/04/99 14:58 - [ 2] Observations Description ------------------------ Our aim is to identify in continuum emission the galaxies at redshifts of 3.4 and 3.89 responsible for damped Lyman-Alpha absorption systems seen in the spectrum of quasar PC 0953+4749. For any emission from the quasar itself to be extinguished, the observations must be conducted at wavelengths less than 4800Angstrom , the (1+z_abs)912Angstrom Lyman limit of another system at z_abs=4.25 The F439W B-band filter is ideal, in that it spans the wavelength range between the Lyman limit of the highest redshift damped system (z=4.25, 4800Angstrom) below which there is no quasar contribution, to the Lyman limit of the lowest redshift system (z=3.4, 4000Angstrom) below which there will be minimal flux. In order to reach a magnitude of 27.4 in B we need to integrate for 11, 000 seconds (4 orbits including overheads) to achieve a signal-to-noise ratio of 5 for an unresolved object (calculated with WFPC2 ETC). We will also obtain a short integration in the F702W R-filter, so that we may accurately determine the position of the QSO, which will be invisible in our B-band data. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- This is the second submission of this Phase II proposal - at the request of STScI, all programs longer than 5 orbits are split to make scheduling easier. This 6-orbit program has been split into two visits, of duration 2- and 4- orbits respectively. ------------------------------------------------------------------------------------ Data Distribution Paper Products: Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 6582( 4) - 01/04/99 14:58 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PC0953+4749 GALAXY, QSO, LYMAN RA=09H 53M 13.845S +/- 0.2S, B1950 Z=4.46 R = 19.47+/-0.04 ALPHA CLOUD, HIGH DEC=47D 49' 9" +/- 2", PLATE- REDSHIFT GALAXY ID=00T8 Comments: B-V>6 6582( 4) - 01/04/99 14:58 - [ 4] Visit: 01 Visit Priority: Visit Requirements: SCHED 30% PCS MODE FINE 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 PC0953+4749 WFPC2 IMAGE WF3-FIX F702W CR-SPLIT=NO,DITHER-TYPE=BOX 1 1200 S ------------------------------------------------------------------------------------------------------------------------------------ 6582( 4) - 01/04/99 14:58 - [ 5] Visit: 02 Visit Priority: Visit Requirements: SCHED 30% PCS MODE FINE GROUP 1-2 WITHIN 30D 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 ------------------------------------------------------------------------------------------------------------------------------------ 20 PC0953+4749 WFPC2 IMAGE WF3-FIX F439W CR-SPLIT=NO,DITHER-TYPE=BOX 1 2800 S ------------------------------------------------------------------------------------------------------------------------------------ 6582( 4) - 01/04/99 14:58 - [ 6] Summary Form for Proposal 6582 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WF3-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO DITHER-TYPE=BOX ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 30% PCS MODE FINE SCHED 30% PCS MODE FINE GROUP 1-2 WITHIN 30D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F702W F439W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PC0953+4749 ------------------------------------------------------------------------------------------------------------------------------------