Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5765 Report Date: 18-Jul-95:17:57 Version: ********** Check-in Date: ********** 1.Proposal Title: DETAILED STUDY OF 4C41.17, THE MOST DISTANT GALAXY - LRF PORTION CYCLE 4, MEDIUM. -- PART I: EARLY ACQUISITION IMAGING. ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO 5511 Sub Category DISTANT GALAXIES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Wil J Van breugel IGPP/LLNL USA 510-422-7195 ------------------------------------------------------------------------------------ 7. Abstract During Cycle 1 we imaged 4C41.17, the most distant galaxy known, with the WFC. Its redshift of 3.8 corresponds to a relative lookback time of ~ 90% and must be close to the epoch at which the galaxies formed. The ultraviolet continuum was detected at high signal to noise. 30% of its flux comes from clumps on the scale of a few hundred parsec. We here propose to carry out an intensive study of this important object with the unaberrated HST using imaging (WFPC2) and spectroscopy (FOS). Our aims are 1) deep continuum imaging to study the morphology of 4C41.17 and possible neighboring cluster galaxies with much better sensitivity and resolution than is possible with our current Cycle 1 images, 2) Ly-a imaging, if possible with the Linear Ramp Filters, to study the Ly-a emission from 4C41.17 and its extensive halo, and 3) FOS spectros- copy of the three brightest clumps to obtain information on the sub- kiloparsec scale about the kinematics and the scale and nature of the absorption clouds which have recently been observed from the ground. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 11.50 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5765 PI: Wil J Van breugel Proposal Title: DETAILED STUDY OF 4C41.17, THE MOST DISTANT GALAXY - LRF PORTION CYCLE 4, MEDIUM. -- PART I: EARLY ACQUISITION IMAGING. ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Wil J Van Breugel 2460 USA George K. Miley 6870 NETHERLANDS X Patrick J. Mcarthy 3030 USA Hyron Spinrad 1500 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Our aim is to study 4C 41.17 and its surrounding field at high spatial resolution. Several sets of observations are proposed. CONTINUUM IMAGING We shall take deep red images, with 4C41.17 placed near the center of PC1. Our choice of filters is dictated by the following criteria. First, bright lines (Lyman alpha) should be excluded from the pass band. Second, the red filter should result in as large as possible detected light signal. The optimum filter, also used in Cyc 1,is F702W. The exposure times will be divided in several exposures for best cosmic ray rejection, but otherwise should be as long as possible in order to go as deep as possible for the given readout noise. Thus we are asking for each subexposure to be about 2400 sec or about a half orbit. These times could be adjusted to maximize observing efficiency, for example during acquisition, but individual exposures should not be less than 30 minutes. However, all exposures should be at the same position and orientation. The basis objective is to go as deep as possible with these exposures. All observations were originally done with coarse-track guiding, but fine lock is chosen here due to the increased likelihood of damage to the teflon coating of some FGS components which oscillate more in coarse track, and since the PC is used. LY-ALPHA IMAGING Lyman alpha imaging will be carried using the linear ramp (1%) filter centered at 5830 A and F569W, which also includes Ly-alpha. The F569W filter includes Ly-alpha and the F569W exposure will provide a backup Lyman alpha image for the FOS acquistion. We regard this as essential in view of the unknown performance of the LRF filter and the possibility of vignetting. The F569W image, will act as a partial check on the LRF images. It is important that we have both sets of Ly-a images BEFORE we do the FOS observations. If the LRF filter is unavailable or unusable, the LRF time should be used to increase the exposure time in the F569W filter. **************************************************************** LRF removed with PI consent, will execute LRF in another program ID. NOTE THAT ALL THE IMAGING OBSERVATIONS WILL BE NEEDED AS EARLY ACQUISITION OBSERVATIONS TO DETERMINE ACCURATE POSITIONS AND OFFSETS FOR LATER FOS SPECTROSCOPY. FOS SPECTROCOPY We would make FOS observations at the positions of the brightest knots of 4C41.17 (labelled H2, H3, and H4). Their positions and offsets relative to a nearby star would have to be determined from earlier WFPC observations (see above). ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The HST is essential to image sub-kiloparsec structure in distant galaxies. Our proposal builds on several years of preparatory ground-based programs. We were involved in the discovery of this object and have access to a huge body of relevant data including: (i) optical images and spectra (Kitt Peak and Lick Observatory) (ii) 2.2 micron images (UKIRT). (iii) radio maps of the total intensity and polarisations at several frequencies and resolutions (VLA, MERLIN at Jodrell Bank, and VLBI). Note that the HST images are comparable in resolution to the best VLA maps. For the first time they allow meaningful comparisons between radio and optical morphologies to be made. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The WFPC imaging observations must preceed the FOS spectroscopy. They are needed as early acquisition observations to determine accurate positions of the 4C41.17 knots (H2, H3, H4) relative to nearby offset star. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. We request that the Ly-a imaging observations will be made prior to the FOS observations in order to help us select the locations of bright Ly-a regions and to determine offsets from nearby stars. To provide a backup for the linear ramp filter we request that that time be used with the F569W filter. ------------------------------------------------------------------------------------ 9. Description of previous HST work. 4C 41.17 was observed for a total of about 3 hours in 5 separate exposures with the WFC through the F702W filter centred near 7000 A. At z=3.8 the 0.1" PSF corresponds to 440 pc (H0 = 75 km/s/Mpc and q0 = 0.5). Our main results were: (i) There is extreme clumpiness on the scale of the HST resolution. Although the emisssion extends for more than 3.5", the structure is concentrated, with about a third of the flux originating from a high-brightness region extending by about 0.5", which we identify with the nucleus of 4C 41.17. Within the nuclear complex, at least three peaks of emission are discernable, each containing about 12% of the integrated emission from the galaxy (R = 22). There is also a more extended extranuclear component, H1, located about 1.2" (5 kpc) from the nucleus, but the structure and extent of this is not well determined. (ii) There is good correspondence between the optical and radio images. The orientation of the nuclear emission of the optical and the radio agree to within about a degree, and the extent is also comparable. The outer peaks of the HST nuclear emission, H2 and H4 can be identified with radio components, B2 and B3 from Chambers et al (1990). (iii) The optical image dispays curvature in the same sense as the radio source. The position angle of the radio structure the west (256 deg from B3 to B1). This curvature towards the northwest is mirrored in the optical image. Although the optical peak H1 does not correspond exactly with the nominal radio peak of B1. In view of the poor signal to noise and large extent of these components, the component peak intensities are ill defined and the lack of exact coincidence is not significant. 4C 41.17 emits a large fraction of its flux (30%) in clumps. Independent of detailed models, the clumpiness implies that considerable inhomogeneities exist in the inner regions of distant radio galaxies. It is tempting to associate the HST clumps with the clouds responsible for the heavy element aborption systems that sometimes occur close to the emission redshifts of some quasars. Further deductions from the HST data depend on the model adopted to explain the radio/optical alignment effect (Chambers, Miley and van Breugel 1987; McCarthy et al. 1987). Several models have been proposed (see McCarthy 1993). The most viable ones are (i) star formation stimulated by the radio jet as it propagates outwards from the nucleus (ii) scattering of light from a hidden quasar by electrons or dust (iii) inverse- comptom scattering of Cosmic Background Radiation and (iv) enhanced radio emission due to interaction with a parent galaxy. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The reduction will take place at the various participating institutions. SDAS/IRAF is running at all of them. In addition to normal instituional support to each of the investigatora, GM has a postdoc allocated to HST research funded jointly by ASTRON and SRON (the Dutch equivalents of NSF and NASA) and is PI in a large EEC project to study distant radio galaxies. ------------------------------------------------------------------------------------ 11. Address Information Page 4 Name: WIL J VAN BREUGEL Category: PI Institution: 2460 Address: INST. OF GEOPHYSICS AND PLANETARY PHYSICS LAWRENCE LIVERMORE NATIONAL LAB., L-413 P.O. BOX 808 City: LIVERMORE State: CA Zip Code: 94550 Country: USA Telephone: 510-422-7195 Telex (or e-mail): wil@sunlight.llnl.gov ------------------------------------------------------------------------------------ Name: GEORGE K. MILEY Category: CON Institution: 6870 Address: LEIDEN OBSERVATORY P.O. BOX 9513 2300 RA City: LEIDEN State: Zip Code: Country: NETHERLANDS Telephone: 31-71-275849 Telex (or e-mail): miley@reusel.leidenuniv.nl ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5765 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 4C41.17 E,315,325 RA= 06H 47M 20.600S +/- 1950 Z=3.800 1 SURF(R)=29.0,SIZE=0.1 +/- 0.05 0647+41 0.03S, 2 F-LINE(1216)=5+/-1E-16,SIZE=0.1+/- DEC=+41D 34' 04.00" +/- 0.3" 3 0.05 SURF(R)=26.5 Comments: CONTINUUM MAGNITUDE AND LINE FLUX GIVEN PER INDIVIDUAL CLUMP OF 0.1" S/N=5 CONTINUUM IN PC1 REQUIRES 5HR FLUXVAL 3 IS FOR IMAGES IN WF CCD'S TO SEARCH FOR CLUSTER MEMBERS. 2HR AT S/N=5 WILL REACH 28.7 MAG FOR POINT SOURCES. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5765 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 4C41.17 WFPC2 IMAGE LRF LRF 5830 CR-SPLIT=0.5 3 2400S 10 1 1 PCS MODE F CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5765 [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 11.50 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category DISTANT GALAXIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE F; CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements LRF ------------------------------------------------------------------------------------------------------------------------------------ Target Names 4C41.17 0647+41 ------------------------------------------------------------------------------------------------------------------------------------