! File: 2373C.PROP ! Database: PEPDB ! Date: 17-FEB-1994:05:39:15 coverpage: title_1: MORPHOLOGY OF GALAXIES IN CLUSTERS AT Z = 0.5 : CYCLE 1 OBSERVATIONS sci_cat: GALAXIES & CLUSTERS sci_subcat: EVOLUTION/COSMOLOGY proposal_for: GO longterm: 2 pi_title: DR. pi_fname: ALAN pi_lname: DRESSLER pi_inst: THE OBSERVATORIES OF THE CARNEGIE INSTITUTION OF WASHINGTON pi_country: USA pi_phone: 818-304-0245 keywords_1: GALAXY MORPHOLOGY, EVOLUTION, GALAXY CLUSTER hours_pri: 11.00 num_pri: 1 wf_pc: Y funds_amount: 80000 funds_length: 12 funds_date: JUL-91 pi_position: ASTRONOMER off_fname: ALAN off_lname: DRESSLER off_title: STAFF MEMBER off_inst: THE OBSERVATORIES OF THE CARNEGIE INSTITUTION OF WASHINGTON off_addr_1: 813 SANTA BARBARA ST. off_city: PASADENA off_state: CA off_zip: 91101 off_country: USA off_phone: 818-304-0245 off_telex: 15613818 OCIW UT ! end of coverpage abstract: line_1: Our program is intended to study galaxy evolution through the line_2: investigation of galaxy morphology as a function of lookback line_3: time. The development of disks and bulges, the role of line_4: mergers, interactions, and other environmental influences, line_5: are expected to be visible over the range 0 < z < 1 as line_6: judged by the spectrophotometric evolution already observed line_7: over this redshift The approved Cycle I version of this line_8: two year program called for imaging with the Wide Field line_9: Camera 5 fields in four rich clusters of galaxies at z = line_10: 0.35 - 0.55 for which extensive photometry and spectroscopy line_11: already exist. The fields included a wide range of line_12: environments from the dense cores of clusters to isolated line_13: field galaxies. These data were to be used to classify line_14: images according to traditional morphological categories line_15: and will be used to determine quantitative measures of line_16: surface brightness distributions and bulge-to-disk ratios. line_17: Due to the SA of the HST optical system, the new goal is to line_18: image a single field in one color for three times the line_19: exposure (10 hours total) in order to assess the feasibility line_20: of these goals with the present performance of the system. ! ! end of abstract general_form_proposers: lname: BUTCHER fname: HARVEY title: PROF. inst: KAPTEYN OBSERVATORY country: NETHERLANDS esa: Y ! lname: OEMLER fname: AUGUSTUS, JR. title: PROF. inst: DEPARTMENT OF ASTRONOMY, YALE UNIVERSITY country: USA ! lname: DRESSLER fname: ALAN title: P.I. inst: THE OBSERVATORIES OF THE CARNEGIE INSTITUTION OF WASHINGTON country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 0 line_1: The original approved program called for imaging with the line_2: WFC of 5 fields in 4 clusters 0.36 < z < 0.55 in the first line_3: year of a two-year program. Ground-based CCD images of line_4: these fields were used to select a WFC field which includes line_5: an area for which multicolor photometry for most objects line_6: and low resolution spectroscopy for some objects are line_7: already in hand. A typical field will contain 1 line_8: contaminating field galaxy for every 2 cluster galaxies, line_9: so the sample covers a wide range of environments. The line_10: spectra have been classified according to "activity", line_11: related to star formation or an active nucleus. line_13: We have now chosen a single field in one of the lowest line_14: redshifts clusters of our sample, Cl0024-1653, in order to line_15: evaluate the degradation due to SA in the HST optical line_16: system, and the ability of deconvolution techniques to line_17: recoup some of these losses. The field center has been line_18: chosen to maximize the number of "active" galaxies. line_19: Observations will be coadded single-orbit exposures of line_20: 15,000 s in one broad-band color, roughly corresponding to line_21: rest-frame B. This will be directly comparable to line_22: morphological classification at low redshift which is line_23: traditionally done in this color. ! question: 4 section: 0 line_1: Morphology is the missing component in our attempts to line_2: study galaxy evolution for 0 < z < 1. At the distance line_3: of our intended targets, 1 arcsecond = 7 1/h kpc, so line_4: morphological classification is extremely crude with line_5: ground-based seeing of FWHM = 0.5-1.0 arcseconds. No line_6: meaningful comparisons can be made with low-z classification line_7: systems. The HST with the WFC, with its field of 2.7 x 2.7 line_8: arcminutes and 0.1 arcsecond pixels, affords us the only line_9: opportunity to fundamentally correct this deficiency. line_10: Though not as detailed as the classification of galaxies line_11: within the Local Supercluster, where resolutions of order line_12: 100 pc can be obtained, imaging with resolutions of order line_13: 1 kpc has thus been shown to be sufficient to distinguish line_14: between the major classes in the Hubble or de Vaucouleurs line_15: schemes. Before the discovery of SA in the HST optical line_16: system, it was anticipated that nearly the same resolution line_17: of 0.7 1/h kpc could be obtained for galaxies in clusters line_18: at z = 0.5. The present plan is to test the degree to line_19: which the poorer resolution impacts the program, and to line_20: what extent higher S/N ratio imaging combined with line_21: deconvolution can restore the original capability. ! question: 5 section: 0 line_1: From CCD images of low-z cluster spirals we simulated line_2: HST observations and concluded that, for clusters line_3: at z = 0.4, exposures of 15,000 s (6 x 2500 s single-orbit) line_4: exposures would be required for a S/N = 20, necessary even line_5: for rudimentary classification. We have arrived at these line_6: numbers by obtaining CCD images of spiral galaxies in line_7: low-redshift clusters and using them to simulate exposures line_8: with the HST WFC, taking into account telescope and detector line_9: efficiency, dark current, readout noise, resolution, and line_10: sampling. However, these simulations did not take into line_11: account the poorer optical performance of HST. In light of line_12: this, we have obtained computer simulations done by William line_13: Keel for HST imaging projects of Windhorst et al. that make line_14: use of a V=20 mag spiral at z = 0.3. From these tests we line_15: expect that the gross features like spiral structure should line_16: be discernible in an exposure of approximately 30,000 s in line_17: a cluster at z = 0.40, particularly if a fair fraction of line_18: the light is in point sources (H-II regions) and sufficient line_19: S/N ratio is reached to allow successful deconvolution. line_20: We have not included the possibility that evolution may make line_21: such features easier to detect. We will propose further line_22: cluster observaions in Cycle 2 or abandon the program for line_23: the present depending on the the results of this test. ! question: 7 section: 0 line_1: In order to accomplish our scientific objectives line_2: we must develop methods of moving from images to line_3: parametrized data. Traditionally this has been accomplished line_4: by using the image processing capabilities of the human eye line_5: plus brain, in order to assign morphological classes, line_6: estimate bulge-to-disk ratios, and describe distributions of line_7: color, dust, non-axisymmetric structures, etc. These line_8: classifications are semi-quantitative at best, and useful line_9: results regarding the evolution of galaxy morphology will line_10: depend on having an equivalent sample of observations at low line_11: redshift for which the same subjective criteria can be line_12: applied. With this in mind, Dressler has begun to line_13: obtain CCD images of low redshift clusters 0.02 < z < 0.04 line_14: in seeing of FWHM < 1 arcsecond. With suitable processing, line_15: such data can be used to simulate the HST observations line_16: (similar sampling, S/N, and resolution) in order to provide line_17: calibration images. Thus, although the criteria will be line_18: remain subjective in this initial step, it can be applied so line_19: that redshift is the only significant variable, and a good line_20: assessment of differential morphology can be made. line_22: Of course, deconvolution techniques will play a major role line_23: in the processing of these data. ! question: 10 section: 0 line_1: Dressler and Oemler each have access to a MicroVAX line_2: computer with image display capability. Each MicroVAX is line_3: part of a VAX system, supplied and maintained individually line_4: by MWLCO and Yale which includes a variety of line_5: I/O devices and access to BITNET and other communication line_6: networks. ! !end of general form text general_form_address: lname: DRESSLER fname: ALAN title: DR. category: PI inst: THE OBSERVATORIES OF THE CARNEGIE INSTITUTION OF WASHINGTON addr_1: 813 SANTA BARBARA ST. city: PASADENA state: CA zip: 91101 country: USA phone: 818-304-0245 telex: 1561318 OCIW UT from_date: 01-OCT-89 to_date: 31-DEC-92 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: GAL-CLUS-002400+165300-FLD1 descr_1: Z = 0.39 CLUSTER OF GALAXIES pos_1: RA= 00H23M56.2S +/-0.1S, pos_2: DEC= +16D53'19" +/-1" equinox: 1950.0 pm_or_par: N rv_or_z: Z=0.39 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: MEXP targname: # config: WFC opmode: IMAGE aperture: ALL sp_element: # num_exp: # time_per_exp: 2100S priority: # param_1: CR-SPLIT=NO, param_2: PRE-FLASH=NO comment_1: THIS SEQUENCE IS INTENDED TO FIT comment_2: EACH EXPOSURE INTO 1 ORBIT. comment_3: ADJUST EXPOSURE TIME +/- 20 PERCENT comment_4: TO ACCOMPLISH. comment_5: THIS IS THE CYCLE 1 VERSION OF THIS comment_6: PROPOSAL: AD 91/04/10 ! linenum: 1.900 targname: GAL-CLUS-002400+165300-FLD1 config: WFC opmode: IMAGE aperture: ALL sp_element: F702W num_exp: 1 time_per_exp: 700S priority: 1 param_1: CR-SPLIT=NO, param_2: PRE-FLASH=NO req_1: CYCLE 1 / 1.9-3; req_2: POS TARG 0,0 / 1.9-2; comment_1: THIS LINE ADDED PER SPB REQUEST AND comment_2: WITH OK FROM PI. RAL 28/06/91 ! linenum: 2.000 sequence_1: USE sequence_2: MEXP targname: GAL-CLUS-002400+165300-FLD1 sp_element: F702W num_exp: 9 priority: 1 ! linenum: 3.000 sequence_1: USE sequence_2: MEXP targname: GAL-CLUS-002400+165300-FLD1 sp_element: F702W num_exp: 8 priority: 1 req_1: POS TARG 2,3; comment_1: OFFSET 2 ARCSEC IN RA AND 3 ARCSEC IN comment_2: DEC TO REMOVE POSSIBLE EFFECTS comment_3: ASSOCIATED WITH INDIVIDUAL PIXELS AND comment_4: POINT SPREAD FUNCTIONS. THIS LINE comment_5: ADDED PER REQUEST FROM PI. RAL - comment_6: AUG. 1991 ! ! end of exposure logsheet ! No scan data records found