! $Id: 5396,v 5.1 1994/07/27 17:29:57 pepsa Exp $ coverpage: title_1: THE FORMATION OF GLOBULAR CLUSTERS DURING MERGERS sci_cat: GALAXIES & CLUSTERS sci_subcat: PECULIAR/INTERACTING proposal_for: GO pi_fname: STEPHEN pi_mi: E pi_lname: ZEPF pi_inst: UNIVERSITY OF CALIFORNIA, BERKELEY pi_country: USA pi_phone: 510-642-5275 hours_pri: 7.20 num_pri: 4 wf_pc: Y off_fname: JONATHAN off_lname: ARENS off_title: DR. off_inst: 1500 off_addr_1: UNIVERSITY OF CALIFORNIA off_addr_2: DEPARTMENT OF ASTRONOMY off_addr_3: CAMPBELL HALL off_city: BERKELEY off_state: CA off_zip: 94720 off_country: USA off_phone: 510-642-5275 ! end of coverpage abstract: line_1: Both theoretical and observational studies have demonstrated line_2: that elliptical galaxies can form through the merger of spirals. line_3: However, if most ellipticals formed in this way, new globular clusters line_4: must be formed during mergers. This is required to reconcile the merger line_5: hypothesis with the higher specific frequency of globular clusters line_6: around ellipticals relative to spirals. We have previously proposed line_7: that the formation of new globular clusters is a natural outcome of line_8: the merger process. Ground-based data provide some evidence for the line_9: existence of young globulars in mergers, but do not have sufficient line_10: resolution to distinguish globulars from more extended star formation line_11: regions. Results from the two relevant galaxies which have been line_12: imaged by the WFPC1 demonstrate the promise of space-based resolution, line_13: but are somewhat limited by the broad wings of the psf. Therefore, line_14: we propose to obtain images with the WFPC2 of a sample of four merging line_15: systems, carefully chosen from our ground-based survey to represent line_16: a range of merging states. Since the formation of new globular line_17: clusters is required if ellipticals are the products of spiral line_18: mergers, this program is a very economical way to test the merger line_19: hypothesis. ! ! end of abstract general_form_proposers: lname: ZEPF fname: STEPHEN mi: E inst: 1500 country: USA ! lname: ASHMAN fname: KEITH mi: M inst: 2400 country: USA ! lname: ENGLISH fname: JAYANNE inst: 4140 country: AUSTRALIA ! lname: FREEMAN fname: KENNETH mi: C inst: 4140 country: AUSTRALIA ! lname: SHARPLES fname: RAY mi: M inst: 8018 country: UNITED KINGDOM ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: The WFPC2 will be used with the F450W and F814W filters to image line_2: four galaxies which are commonly believed to be recent mergers line_3: (NGC 1487, NGC 3256, NGC 3597, and Arp 230). For each galaxy the line_4: exposures will be 25M in the F450W filter and 20M in the F814W line_5: filter. We will divide these into two paired exposures in order line_6: to facilitate cosmic ray removal and to allow for reality checks line_7: on phenomena seen in individual frames. line_9: For the two cases in which the field of view of the PC2 adequately line_10: covers the main body of the galaxy (NGC 3597 and Arp 230), we line_11: will center the galaxy in the PC2 and observe in this position. line_12: For the two galaxies for which more spatial coverage is required line_13: (NGC 1487 and NGC 3256), we will use two separate exposures, line_14: shifting slightly (30 arcseconds) between locations. This line_15: procedure gives sufficient spatial coverage. For NGC 1487, line_16: we are also able to keep the orientation the same, so the line_17: only one guide star acquisition is required. This may not be line_18: true for NGC 3256, in which we are also changing the orientation. ! question: 3 section: 2 line_1: NOTE: Due to duplication issues versus GTOs, the following two targets and line_2: their corresponding observations have been removed from the program on the line_3: instructions of the Director of STScI: line_4: Arp 230 and NGC 3597. ! question: 4 section: 1 line_1: The high resolution imaging capabilities of the HST and WFPC2 line_2: are essential for distinguishing between young globular clusters line_3: which have high spatial densities and are truly equivalent to old line_4: globular clusters in all respects except age, and more extended line_5: star-forming complexes which should not be compared to globular line_6: clusters. This distinction is central to determining whether the line_7: specific frequency of globular clusters rules out a merger origin line_8: for elliptical galaxies or if the problem is solved by the formation line_9: of new globulars during mergers line_11: We have recently completed a program of deep imaging of merging line_12: galaxies with 4m class telescopes. From these data, we have line_13: identified candidate young globular clusters. However, at a line_14: typical distance of the galaxies in our sample (about 30 Mpc), the line_15: half-mass radius of globular clusters is about 0.05 arcseconds. line_16: Therefore, the spatial resolution of the Planetary Camera 2 is line_17: critical for addressing the question of the size of the candidate line_18: young clusters. Moreover, even with exposure times of only 1200s, line_19: the PC2 images will detect young globulars clusters over the whole line_20: range of expected luminosities, thereby allowing a much more line_21: detailed study of the properties of the young cluster system. ! question: 4 section: 2 line_1: We request exposure times totalling 1500s in the F450W and 1200s line_2: in the F814W filter. We estimate that this will give a S/N of 10 line_3: within a radius of 0.1'' for globular clusters of B = 25 and I = 24. line_4: This calculation assumes the clusters have the color of an F0 star line_5: and lie on a galaxy background of B = 20 magnitudes/arcsec^2 and line_6: I = 18.5 magnitudes/arcsec^2. line_8: We expect nearly all of the young globulars and about half of the line_9: old ones to be brighter than this limit for the typical galaxy in line_10: our sample. This S/N will be clearly sufficient to determine if the line_11: candidate young globular clusters have the high central stellar line_12: density characteristic of true globular clusters. Moreover, since line_13: we will also detect old globular clusters in our images, we can line_14: compare the sizes of the two populations directly. We will also line_15: be able to study the shapes of the brighter young globulars in line_16: more detail. Furthermore, we will obtain precise B-I colors which line_17: form the basis for a determination of the age of the young globular line_18: clusters. ! question: 5 section: 1 line_1: None. ! question: 6 section: 1 line_1: None ! ! question: 8 section: 1 line_1: None. ! question: 9 section: 1 line_1: Cycle 3 line_3: No. 4423 "The Formation of Globular Clusters during Mergers" line_4: (same team as this proposal). Chosen for Supplemental Pool. line_6: Cycle 2 line_8: No. 3647 "The Star Forming Histories of Elliptical Galaxies" line_9: (Zepf co-I). line_11: Cycle 1 line_13: No. 2147 "Disk and Halo Globular Clusters in the Edge-On Spiral line_14: Galaxy 5170" (Freeman co-I) line_15: No. 2269 "Galaxy Populations in Intermediate Redshift Clusters" line_16: (Sharples co-I). ! question: 9 section: 2 line_1: Only the Supplemental Cycle 3 program is related to this proposal. line_2: No data has yet been obtained for that program. ! question: 9 section: 3 line_1: `Deep Wide Field Camera Images of a z=0.3 Cluster' Couch, W.J., line_2: Ellis, R.S., & Sharples, R. 1992, ST-ECF Newsletter, No. 17, p. 13. line_4: `Deep WFC Imaging of the z=0.3 Cluster AC114' Sharples, R.M., line_5: Smail, I.R., Ellis, R.S., Couch, W.J., Fitchett, M.J. & Jorgensen, line_7: `Morphological Studies of Galaxy Populations in Distant BO Custers' line_8: Couch, W.J., Ellis, R.S., Sharples, R.M., & Smail, I.R. 1993, in line_9: `Observational Cosmology', ed. G. Chincarini, ASP Conference Series, line_10: in press. ! question: 10 section: 1 line_1: UC Berkeley, Durham University, and Mount Stromlo and Siding Spring line_2: Observatory provide excellent computing facilities based on UNIX line_3: workstations running the IRAF/STSDAS software package. The national line_4: observatory facilities of both the UK and Australia have already line_5: generously supported the ground-based aspects of this program. ! !end of general form text general_form_address: lname: Zepf fname: Stephen mi: E category: PI inst: 1500 addr_1: University of California addr_2: Department of Astronomy addr_3: Campbell Hall city: Berkeley state: CA zip: 94720 country: USA phone: 510-642-2359 telex: 510-642-3411 ! lname: category: CON ! ! end of general_form_address records fixed_targets: targnum: 2 name_1: NGC1487-POS1 descr_1: E,320,318,918 pos_1: RA = 03H 55M 45.3S +/- 1.0", pos_2: DEC = -42D 22' 10.0" +/- 1.0" equinox: J2000 rv_or_z: V=856 comment_1: FLUX VALUES ARE FOR CANDIDATE comment_2: YOUNG GLOBULAR CLUSTERS WITHIN comment_3: THE TARGET GALAXIES fluxnum_1: 1 fluxval_1: V=23. fluxnum_2: 2 fluxval_2: V-I=0.5+/-0.3 fluxnum_3: 3 fluxval_3: SURF-BKG(V)=20+/-0.5 fluxnum_4: 4 fluxval_4: SURF-BKG(I)=19+/-0.5 ! targnum: 3 name_1: NGC1487-POS2 descr_1: E,320,318,918 pos_1: RA = 03H 55M 45.3S +/- 1.0", pos_2: DEC = -42D 22' 30.0" +/- 1.0" equinox: J2000 rv_or_z: V=856 comment_1: FLUX VALUES ARE FOR CANDIDATE comment_2: YOUNG GLOBULAR CLUSTERS WITHIN comment_3: THE TARGET GALAXIES fluxnum_1: 1 fluxval_1: V=23. fluxnum_2: 2 fluxval_2: V-I=0.5+/-0.3 fluxnum_3: 3 fluxval_3: SURF-BKG(V)=20+/-0.5 fluxnum_4: 4 fluxval_4: SURF-BKG(I)=19+/-0.5 ! targnum: 4 name_1: NGC3256-POS1 descr_1: E,320,318,918 pos_1: RA=10H 27M 51.0S +/- 1.0", pos_2: DEC=-43D 54' 15.0" +/- 1.0" equinox: J2000 rv_or_z: V=2821 comment_1: FLUX VALUES ARE FOR CANDIDATE comment_2: YOUNG GLOBULAR CLUSTERS WITHIN comment_3: THE TARGET GALAXIES fluxnum_1: 1 fluxval_1: V=23. fluxnum_2: 2 fluxval_2: V-I=0.5+/-0.3 fluxnum_3: 3 fluxval_3: SURF-BKG(V) = 20 +/- 0.5 fluxnum_4: 4 fluxval_4: SURF-BKG(I) = 19 +/- 0.5 ! targnum: 5 name_1: NGC3256-POS2 descr_1: E,320,318,918 pos_1: RA=10H 27M 49.0S +/- 1.0", pos_2: DEC=-43D 54' 27.0" +/- 1.0" equinox: J2000 rv_or_z: V=2821 comment_1: FLUX VALUES ARE FOR CANDIDATE comment_2: YOUNG GLOBULAR CLUSTERS WITHIN comment_3: THE TARGET GALAXIES fluxnum_1: 1 fluxval_1: V=23. fluxnum_2: 2 fluxval_2: V-I=0.5+/-0.3 fluxnum_3: 3 fluxval_3: SURF-BKG(V) = 20 +/- 0.5 fluxnum_4: 4 fluxval_4: SURF-BKG(I) = 19 +/- 0.5 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 3.000 targname: NGC1487-POS1 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F814W num_exp: 1 time_per_exp: 1600S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 4 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4; req_2: ORIENT 150D +/- 30D comment_1: CR-TOLERANCE OF 0.0 IS NOT comment_2: ABSOLUTELY REQUIRED. IT CAN BE comment_3: RELAXED TO 0.1 IF NECESSARY. comment_4: REQUESTED ORIENTATION ON SKY IS comment_5: WF CCDS ROUGHLY NORTHWEST OF PC2 comment_6: THIS CAN BE FLEXIBLE IF NECESSARY ! linenum: 4.000 targname: NGC1487-POS1 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F450W num_exp: 1 time_per_exp: 1800S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4 / 3-4; req_2: SEQ 3-4 NO GAP; req_3: SAME POS FOR 4 AS 3 comment_1: REQUIREMENTS 2 AND 3 (GROUP 3-4 comment_2: WITHIN 7D) AND SAME ORIENT FOR 4 AS 3 comment_3: CAN BE REPLACED BY GROUP 3-4 NO GAP comment_4: IF THAT MAKES SCHEDULING EASIER. comment_5: ORIENTATION MUST STILL BE VERY comment_6: CLOSE (1D) TO PREVIOUS EXPOSURE ! linenum: 5.000 targname: NGC1487-POS2 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F814W num_exp: 1 time_per_exp: 1600S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 4 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4; req_2: ORIENT 150D +/- 30D comment_1: CR-TOLERANCE OF 0.0 IS NOT comment_2: ABSOLUTELY REQUIRED. IT CAN BE comment_3: RELAXED TO 0.1 IF NECESSARY. comment_4: REQUESTED ORIENTATION ON SKY IS comment_5: WF CCDS ROUGHLY NORTHWEST OF PC2 comment_6: THIS CAN BE FLEXIBLE IF NECESSARY ! linenum: 6.000 targname: NGC1487-POS2 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F450W num_exp: 1 time_per_exp: 1800S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4 / 5-6; req_2: SEQ 5-6 NO GAP; req_3: SAME POS FOR 6 AS 5 comment_1: REQUIREMENTS 2 AND 3 (GROUP 5-6 comment_2: WITHIN 7D) AND SAME ORIENT FOR 6 AS 5 comment_3: CAN BE REPLACED BY GROUP 5-6 NO GAP comment_4: IF THAT MAKES SCHEDULING EASIER. comment_5: ORIENTATION MUST STILL BE VERY comment_6: CLOSE (1D) TO PREVIOUS EXPOSURE. ! linenum: 7.000 targname: NGC3256-POS1 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F814W num_exp: 1 time_per_exp: 1600S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 4 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4; req_2: ORIENT 217D +/- 40D comment_1: CR-TOLERANCE OF 0.0 IS NOT comment_2: ABSOLUTELY REQUIRED. IT CAN BE comment_3: RELAXED TO 0.1 IF NECESSARY. comment_4: REQUESTED ORIENTATION ON SKY IS comment_5: WF CCDS ROUGHLY NORTHEAST OF PC2 comment_6: THIS CAN BE FLEXIBLE IF NECESSARY ! linenum: 8.000 targname: NGC3256-POS1 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F450W num_exp: 1 time_per_exp: 1800S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4 / 7-8; req_2: SEQ 7-8 NO GAP; req_3: SAME POS FOR 8 AS 7 comment_1: REQUIREMENTS 2 AND 3 (GROUP 7-8 comment_2: WITHIN 7D) AND SAME ORIENT FOR 8 AS 7 comment_3: CAN BE REPLACED BY GROUP 7-8 NO GAP comment_4: IF THAT MAKES SCHEDULING EASIER. comment_5: ORIENTATION MUST STILL BE VERY comment_6: CLOSE (1D) TO PREVIOUS EXPOSURE. ! linenum: 9.000 targname: NGC3256-POS2 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F814W num_exp: 1 time_per_exp: 1600S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 4 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4; req_2: ORIENT 145D +/- 50D comment_1: CR-TOLERANCE OF 0.0 IS NOT comment_2: ABSOLUTELY REQUIRED. IT CAN BE comment_3: RELAXED TO 0.1 IF NECESSARY. comment_4: REQUESTED ORIENTATION ON SKY IS comment_5: WF CCDS ROUGHLY NORTHWEST OF PC2 comment_6: THIS CAN BE FLEXIBLE IF NECESSARY ! linenum: 10.000 targname: NGC3256-POS2 config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F450W num_exp: 1 time_per_exp: 1800S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: CR-SPLIT = 0.5 param_2: CR-TOLERANCE=0.0 req_1: CYCLE 4 / 9-10; req_2: SEQ 9-10 NO GAP; req_3: SAME POS FOR 10 AS 9 comment_1: REQUIREMENTS 2 AND 3 (GROUP 9-10 comment_2: WITHIN 7D) AND SAME ORIENT FOR 10 AS 9 comment_3: CAN BE REPLACED BY GROUP 9-10 NO GAP comment_4: IF THAT MAKES SCHEDULING EASIER. comment_5: ORIENTATION MUST STILL BE VERY comment_6: CLOSE (1D) TO PREVIOUS EXPOSURE. ! ! end of exposure logsheet ! No scan data records found