! $Id: 5511,v 8.1 1994/07/27 18:47:54 pepsa Exp $ coverpage: title_1: DETAILED STUDY OF 4C41.17, THE MOST DISTANT GALAXY title_2: CYCLE 4, MEDIUM. -- PART I: EARLY ACQUISITION IMAGING. sci_cat: GALAXIES & CLUSTERS sci_subcat: DISTANT GALAXIES proposal_for: GO pi_fname: WIL pi_mi: J pi_lname: VAN BREUGEL pi_inst: IGPP/LLNL pi_country: USA pi_phone: 510-422-7195 hours_pri: 11.50 num_pri: 1 wf_pc: Y off_fname: CHARLES off_lname: ALCOCK off_title: DIRECTOR, IGPP/LLNL off_inst: 2460 off_addr_1: INST. OF GEOPHYSICS AND PLANETARY PHYSICS off_addr_2: LAWRENCE LIVERMORE NATIONAL LAB., L-413 off_addr_3: P.O. BOX 808 off_city: LIVERMORE off_state: CA off_zip: 94550 off_country: USA off_phone: 510-423-0666 ! end of coverpage abstract: line_1: During Cycle 1 we imaged 4C41.17, the most distant galaxy known, with line_2: the WFC. Its redshift of 3.8 corresponds to a relative lookback time of line_3: ~ 90% and must be close to the epoch at which the galaxies formed. The line_4: ultraviolet continuum was detected at high signal to noise. 30% of its line_5: flux comes from clumps on the scale of a few hundred parsec. We here line_6: propose to carry out an intensive study of this important object with line_7: the unaberrated HST using imaging (WFPC2) and spectroscopy (FOS). line_8: Our aims are 1) deep continuum imaging to study the morphology of 4C41.17 line_9: and possible neighboring cluster galaxies with much better sensitivity line_10: and resolution than is possible with our current Cycle 1 images, 2) line_11: Ly-a imaging, if possible with the Linear Ramp Filters, to study the line_12: Ly-a emission from 4C41.17 and its extensive halo, and 3) FOS spectros- line_13: copy of the three brightest clumps to obtain information on the sub- line_14: kiloparsec scale about the kinematics and the scale and nature of the line_15: absorption clouds which have recently been observed from the ground. ! ! end of abstract general_form_proposers: lname: VAN BREUGEL fname: WIL mi: J inst: 2460 country: USA ! lname: MILEY fname: GEORGE mi: K. inst: 6870 country: NETHERLANDS esa: Y ! lname: MCARTHY fname: PATRICK mi: J. inst: 3030 country: USA ! lname: SPINRAD fname: HYRON inst: 1500 country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Our aim is to study 4C 41.17 and its surrounding field at high spatial line_2: resolution. Several sets of observations are proposed. line_3: CONTINUUM IMAGING line_4: We shall take deep red images, with 4C41.17 placed near the center line_5: of PC1. line_6: Our choice of filters is dictated by the following criteria. First, line_7: bright lines (Lyman alpha) should be excluded from the line_8: pass band. Second, the red filter should result in as large as possible line_9: detected light signal. The optimum filter, also used in Cyc 1,is F702W. line_11: The exposure times will be divided in several exposures for best line_12: cosmic ray rejection, but otherwise should be as long as possible in line_13: order to go as deep as possible for the given readout noise. Thus we line_14: are asking for each subexposure to be about 2400 sec or about a half line_15: orbit. These times could be adjusted to maximize observing efficiency, line_16: for example during acquisition, but individual exposures should not be line_17: less than 30 minutes. However, all exposures should be at the same line_18: position and orientation. ! question: 3 section: 2 line_1: The basis objective is to go as deep as possible with these exposures. line_2: All observations were originally done with coarse-track guiding, but line_3: fine lock is chosen here due to the increased likelihood of damage to line_4: the teflon coating of some FGS components which oscillate more in line_5: coarse track, and since the PC is used. line_7: LY-ALPHA IMAGING line_8: Lyman alpha imaging will be carried using the linear ramp (1%) filter line_9: centered at 5830 A and F569W, which also includes Ly-alpha. line_10: The F569W filter includes Ly-alpha line_11: and the F569W exposure will provide a backup Lyman alpha line_12: image for the FOS acquistion. We regard this as essential in view line_13: of the unknown performance of the LRF filter and the possibility of line_14: vignetting. The F569W image, will act as a partial check on the LRF line_15: images. It is important that we have both sets of Ly-a images BEFORE line_16: we do the FOS observations. line_17: If the LRF filter is unavailable or unusable, the LRF time line_18: should be used to increase the exposure time in the F569W filter. line_19: **************************************************************** line_20: LRF removed with PI consent, will execute LRF in another program ID. line_21: NOTE THAT ALL THE IMAGING OBSERVATIONS WILL BE NEEDED AS EARLY line_22: ACQUISITION OBSERVATIONS TO DETERMINE ACCURATE POSITIONS AND line_23: OFFSETS FOR LATER FOS SPECTROSCOPY. ! question: 3 section: 4 line_1: FOS SPECTROCOPY line_2: We would make FOS observations at the positions of the brightest knots line_3: of 4C41.17 (labelled H2, H3, and H4). Their positions and offsets line_4: relative to a nearby star would have to be determined from earlier line_5: WFPC observations (see above). ! question: 4 section: 1 line_1: The HST is essential to image sub-kiloparsec structure in distant line_2: galaxies. line_4: Our proposal builds on several years of preparatory ground-based line_5: programs. We were involved in the discovery of this object and have line_6: access to a huge body of relevant data including: line_7: (i) optical images and spectra (Kitt Peak and Lick Observatory) line_8: (ii) 2.2 micron images (UKIRT). line_9: (iii) radio maps of the total intensity and polarisations at several line_10: frequencies and resolutions (VLA, MERLIN at Jodrell Bank, and VLBI). line_12: Note that the HST images are comparable in resolution to the best VLA line_13: maps. For the first time they allow meaningful comparisons between line_14: radio and optical morphologies to be made. ! question: 5 section: 1 line_1: The WFPC imaging observations must preceed the FOS spectroscopy. line_2: They are needed as early acquisition observations to determine line_3: accurate positions of the 4C41.17 knots (H2, H3, H4) relative to line_4: nearby offset star. ! question: 6 section: 1 line_1: ! ! question: 8 section: 1 line_1: We request that the Ly-a imaging observations will be made prior to line_2: the FOS observations in order to help us select the locations of line_3: bright Ly-a regions and to determine offsets from nearby stars. line_4: To provide a backup for the linear ramp filter we request that line_5: that time be used with the F569W filter. ! question: 9 section: 1 line_1: 4C 41.17 was observed for a total of about 3 hours in 5 separate line_2: exposures with the WFC through the F702W filter centred near 7000 A. At line_3: z=3.8 the 0.1" PSF corresponds to 440 pc (H0 = 75 km/s/Mpc and q0 = line_4: 0.5). Our main results were: line_5: (i) There is extreme clumpiness on the scale of the HST resolution. line_6: Although the emisssion extends for more than 3.5", the structure is line_7: concentrated, with about a third of the flux originating from a line_8: high-brightness region extending by about 0.5", which we identify with line_9: the nucleus of 4C 41.17. Within the nuclear complex, at least three line_10: peaks of emission are discernable, each containing about 12% of the line_11: integrated emission from the galaxy (R = 22). There is also a more line_12: extended extranuclear component, H1, located about 1.2" (5 kpc) from line_13: the nucleus, but the structure and extent of this is not well line_14: determined. line_16: (ii) There is good correspondence between the optical and radio images. line_17: The orientation of the nuclear emission of the optical and the radio line_18: agree to within about a degree, and the extent is also comparable. The line_19: outer peaks of the HST nuclear emission, H2 and H4 can be identified line_20: with radio components, B2 and B3 from Chambers et al (1990). ! question: 9 section: 2 line_1: (iii) The optical image dispays curvature in the same sense as the line_2: radio source. The position angle of the radio structure line_3: the west (256 deg from B3 to B1). This curvature towards the northwest line_4: is mirrored in the optical image. Although the optical peak H1 does not line_5: correspond exactly with the nominal radio peak of B1. In view line_6: of the poor signal to noise and large extent of these components, the line_7: component peak intensities are ill defined and the lack of exact line_8: coincidence is not significant. line_10: 4C 41.17 emits a large fraction of its flux (30%) line_11: in clumps. Independent of detailed models, the clumpiness implies line_12: that considerable inhomogeneities exist in the inner regions of distant line_13: radio galaxies. It is tempting to associate the HST clumps with the line_14: clouds responsible for the heavy element aborption systems that line_15: sometimes occur close to the emission redshifts of some quasars. line_16: Further deductions from the HST data depend on the model adopted to line_17: explain the radio/optical alignment effect (Chambers, Miley and van line_18: Breugel 1987; McCarthy et al. 1987). Several models have been proposed line_19: (see McCarthy 1993). The most viable ones are (i) star formation line_20: stimulated by the radio jet as it propagates outwards from the nucleus line_21: (ii) scattering of light from a hidden quasar by electrons or dust line_22: (iii) inverse-comptom scattering of Cosmic Background Radiation and line_23: (iv) enhanced radio emission due to interaction with a parent galaxy. ! question: 10 section: 1 line_1: The reduction will take place at the various participating line_2: institutions. SDAS/IRAF is running at all of them. line_4: In addition to normal instituional support to each of the line_5: investigatora, GM has a postdoc allocated to HST research funded line_6: jointly by ASTRON and SRON (the Dutch equivalents of NSF and NASA) and line_7: is PI in a large EEC project to study distant radio galaxies. ! !end of general form text general_form_address: lname: VAN BREUGEL fname: WIL mi: J category: PI inst: 2460 addr_1: INST. OF GEOPHYSICS AND PLANETARY PHYSICS addr_2: LAWRENCE LIVERMORE NATIONAL LAB., L-413 addr_3: P.O. BOX 808 city: LIVERMORE state: CA zip: 94550 country: USA phone: 510-422-7195 telex: wil@sunlight.llnl.gov ! lname: MILEY fname: GEORGE mi: K. category: CON inst: 6870 addr_1: LEIDEN OBSERVATORY addr_2: P.O. BOX 9513 addr_3: 2300 RA city: LEIDEN country: NETHERLANDS phone: 31-71-275849 telex: miley@reusel.leidenuniv.nl ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: 4C41.17 name_2: 0647+41 descr_1: E,315,325 pos_1: RA= 06H 47M 20.600S +/- 0.03S, pos_2: DEC=+41D 34' 04.00" +/- 0.3" equinox: 1950 rv_or_z: Z=3.800 comment_1: CONTINUUM MAGNITUDE AND LINE FLUX comment_2: GIVEN PER INDIVIDUAL CLUMP OF 0.1" comment_3: S/N=5 CONTINUUM IN PC1 REQUIRES 5HR comment_4: FLUXVAL 3 IS FOR IMAGES IN WF CCD'S comment_5: TO SEARCH FOR CLUSTER MEMBERS. comment_6: 2HR AT S/N=5 WILL REACH 28.7 MAG comment_7: FOR POINT SOURCES. fluxnum_1: 1 fluxval_1: SURF(R)=29.0,SIZE=0.1 +/- 0.05 fluxnum_2: 2 fluxval_2: F-LINE(1216)=5+/-1E-16,SIZE=0.1+/-0.05 fluxnum_3: 3 fluxval_3: SURF(R)=26.5 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: 4C41.17 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F702W num_exp: 3 time_per_exp: 2400S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: CR-SPLIT = NO req_1: PCS MODE F; req_2: SAME POS FOR 2-4 AS 1; req_3: GROUP 1-4 WITHIN 21D; req_4: CYCLE 4 comment_1: EARLY ACQ FOR GO/FOS 5388 ! linenum: 2.000 targname: 4C41.17 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F702W num_exp: 3 time_per_exp: 2400S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: CR-SPLIT = NO req_1: PCS MODE F; req_2: CYCLE 4; comment_1: EARLY ACQ FOR GO/FOS 5388 ! linenum: 3.000 targname: 4C41.17 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F702W num_exp: 3 time_per_exp: 2400S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: CR-SPLIT = NO req_1: PCS MODE F; req_2: CYCLE 4; comment_1: EARLY ACQ FOR GO/FOS 5388 ! linenum: 4.000 targname: 4C41.17 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F569W num_exp: 3 time_per_exp: 2400S s_to_n: 10 fluxnum_1: 2 priority: 2 param_1: CR-SPLIT = NO req_1: PCS MODE F; req_2: CYCLE 4; comment_1: EARLY ACQ FOR GO/FOS 5388 ! ! ! end of exposure logsheet ! No scan data records found