! $Id: 5420,v 9.1 1994/12/12 16:45:29 pepsa Exp $ coverpage: title_1: COLOR-MAGNITUDE DIAGRAMS OF GLOBULAR CLUSTERS IN M31: CYCLE4 MEDIUM sci_cat: GALAXIES & CLUSTERS sci_subcat: DISTANCE SCALE proposal_for: GO pi_fname: FLAVIO pi_lname: FUSI PECCI pi_inst: 6426 pi_country: ITALY pi_phone: +39-51-259321 hours_pri: 10.42 hours_par: 10.42 num_pri: 2 num_par: 3 wf_pc: Y foc: Y time_crit: Y off_fname: BRUNO off_lname: MARANO off_title: DIRECTOR off_inst: 6426 off_addr_1: OSSERVATORIO ASTRONOMICO off_addr_2: VIA ZAMBONI 33 off_city: BOLOGNA off_zip: 40126 off_country: ITALY off_phone: +39-51-259404 ! end of coverpage abstract: line_1: The solution of the distance-scale problem is crucial in Astronomy. line_2: The main goals of this program are: a) to improve the accuracy of line_3: globular cluster distance (and age) determinations by deriving the line_4: dependence of Mv(HB) on metallicity and HB morphology, taking advantage line_5: of the M31 globular clusters being in practice all at the same distance; line_6: b) to study the HB morphologies as a function of various parameters line_7: (e.g. metallicity, galactocentric distance, concentration, etc.) for line_8: the essential information they may provide on the formation and early line_9: evolutionary phases of galaxies. Structural parameters (e.g. core line_10: radius, ellipticity, surface brightness profile) can also be derived. line_11: With the allocated observing time we can only obtain Colour-Magnitude line_12: Diagrams of two globular clusters in M31 using the FOC/96 and the line_13: filters F430W (B) and F480LP (V). Besides, two more clusters will be line_14: observed in parallel mode (WFC). With the proposed exposure times line_15: it will be possible to measure HB stars with an accuracy of approximately line_16: 0.1 mag. The number of clusters will not be sufficient to draw any line_17: firm conclusion, but this represents the first important step for an line_18: accurate feasibility study and for additional future observations. ! ! end of abstract general_form_proposers: lname: FUSI PECCI fname: FLAVIO inst: 6426 country: ITALY esa: Y ! lname: BENDINELLI fname: ORAZIO inst: 6460 country: ITALY esa: Y ! lname: CACCIARI fname: CARLA inst: 6426 country: ITALY esa: Y ! lname: FEDERICI fname: LUCIANA inst: 6426 country: ITALY esa: Y ! lname: FERRARO fname: FRANCESCO inst: 6426 country: ITALY esa: Y ! lname: PARMEGGIANI fname: GIANLUIGI inst: 6426 country: ITALY esa: Y ! lname: ZAVATTI fname: FRANCO inst: 6460 country: ITALY esa: Y ! lname: DJORGOVSKY fname: GEORGE S. inst: 1590 country: USA ! lname: KING fname: IVAN R. inst: 1500 country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: The primary targets are: G351 (V=15.16 B-V=0.72) and G280 (V=14.26 line_2: B-V=0.92); the parallel targets are G262 and G272, which can both be line_3: observed in the WFPC2 FOV when G280 is in FOC/96, for an appropriate line_4: value of the roll angle. line_5: The observation setup is FOC/96+F430W and FOC/96+F480LP for primary line_6: observations, and WFPC2+F555W and WFPC2+F814W for the respective line_7: parallel observations. The observing strategy is: line_8: Exp.n.1: FOC/96+F430W on G351 + parallel WFPC2+F555W on generic field line_9: Exp.n.2: same as n.1 with filters F480LP (FOC) and F814W (WFPC2) line_10: Exp.n.3: FOC/96+F430W on G280 + parallel WFPC2+F555W on G262 and G272 line_11: Exp.n.4: same as n.3 with filters F480LP (FOC) and F814W (WFPC2). line_12: Exposures n.3 and 4 require a special orientation in order to have line_13: the two clusters in the parallel field of the WFPC2 while pointing the line_14: FOC/96 on the primary target. The optimum Position Angle (N through E) line_15: is 63D +/- 3D, which places G272 in WF4 and G262 in WF2. line_16: The resulting ORIENT angle is 181D +/- 3D. ! question: 3 section: 2 line_1: The exposure times have been calculated in order to reach S/N=10 line_2: for a typical HB stars F0V at V=25, observed with FOC/96 through the line_3: filters F430W and F480LP. The algorithm used for the exposure time line_4: calculation is that specified in the FOC Handbook, February 1993, line_5: page 72, with the following assumptions: line_6: 1. E(B-V)=0.10 line_7: 2. New optical element characteristics as in Table 3 of the FOC Handbook line_8: 3. Expected energy fraction on the assumed area of 21 pixel square (which line_9: consistently gave the shortest exposure time at a given S/N), as derived line_10: by linear interpolation of the data in Table 8 of the FOC Handbook line_11: 4. Detector background noise = 6.4E-4 counts/pixel/sec line_12: 5. Zodiacal light S10 = 3.0E-7 and 1.3E-7 for the two filters respectively, line_13: as estimated from Figure 41, assuming a zodiacal line intensity line_14: 120/90 S10 units line_15: 6. Zero astronomical background from the cluster or M31. line_16: The algorithm used for the S/N and exposure time calculations of the line_17: parallel observations is based on the procedure specified in the WFPC2 line_18: Handbook, March 1993, Sect. 6. We have used the quantities given in line_19: Tables 6.1, 6.2, 6.4, assuming readout noise rn=14e, and saturation line_20: threshold equal to 60000 cts in the central pixel. ! question: 4 section: 1 line_1: The space resolution of ground-based observations is too poor to allow line_2: the photometry of individual HB stars in any globular cluster in M31 line_3: with the required accuracy. The very interesting data of the clusters line_4: G1 and G219 obtained with the CFHT in excellent seeing conditions for line_5: instance by Heasley et al. (1988, AJ 96, 1312) and Christian and line_6: Heasley (1991, AJ 101, 848) are still largely insufficient for the line_7: purpose of this program. ! question: 5 section: 1 line_1: In order to achieve the proposed scientific goals it is necessary to line_2: observe eventually a statistically significant number of clusters. line_3: Therefore the use of parallel observations with the WFPC2 to observe line_4: those clusters located at the appropriate projected distance from the line_5: FOC is very important to improve the program efficiency. One of our line_6: primary targets (G280) is associated with two parallel targets (G262 line_7: and G272) which both fall in the WFPC2 field of view if the Roll Angle line_8: is 181 +/- 3 deg (see Question 3). line_9: Although the need for the definition of the orientation makes the line_10: scheduling of the observations somewhat less flexible, we believe line_11: that the scientific return and the overall increase of efficiency of line_12: the program fully justify the proposed choice. line_13: The other primary target (G351) does not need any special orientation. ! ! question: 8 section: 1 line_1: Our primary target G351 was already obseved by us during cycle 2 using line_2: FOC/96 + F342W and F140W in order to derive the surface brightness line_3: profile and test the possibility of detecting UV-bright stars. line_4: Stellar photometry was not feasible with the required accuracy due to line_5: the HST optical aberration. We intend to observe this cluster again line_6: now, since it is one of our high priority targets, in order to derive line_7: its color-magnitude diagram. Hence, this is not a duplication of line_8: previous science or observations. ! question: 9 section: 1 line_1: Two GO programs were previously granted observing time, namely GO 2583 line_2: (cycle 1) and GO 3726 (cycle 2). With GO 2583 13 clusters were observed line_3: with FOC/96 + F430W and accurate surface brightness profiles were line_4: obtained, along with the related photometric and structural parameters. line_5: These results are of far superior quality than what can be obtained line_6: from ground-based observations of M31 globular clusters, and are line_7: comparable to the results on galactic globular clusters. The two cluster line_8: families show very similar characteristics. We have found the first line_9: evidence of a PCC cluster in M31. These results have been presented line_10: at the Workshop ``Science with the Hubble Space Telescope'' held in line_11: Baia Chia in July 1992 and in two papers published on ApJ and AA. line_12: With GO 3726 one cluster was observed with FOC/96 + F342W and F140W line_13: in order to explore the possibility of obtaining a UV C-M diagram of at line_14: least the brightest and hottest stars even in presence of the known HST line_15: aberration. The data reduction and analysis is presently being carried on, line_16: but it is evident that only the restored HST can provide useful results. ! question: 10 section: 1 line_1: Data Analysis capabilities: Our Institute in Bologna is equipped with various line_2: Workstations (DEC) plus numerous peripherals specifically devoted to the line_3: analysis of HST data. line_4: Research assistance and students: there are typically 10 graduate students in line_5: Astronomy in Bologna, part of them already working on HST-related projects. line_6: Research assistance will be secured. line_7: Funds: our personal research grants are sufficient to cover all the expenses line_8: that may be required to carry on this HST project. The facilities of the ST-ECF line_9: are also available, if needed. American co-investigators will submit a separate line_10: request for funds. ! !end of general form text general_form_address: lname: FUSI PECCI fname: FLAVIO category: PI inst: 6426 addr_1: OSSERVATORIO ASTRONOMICO addr_2: VIA ZAMBONI 33 city: BOLOGNA zip: 40126 country: ITALY phone: +39-51-259321 telex: (SPAN) 37907::FLAVIO, fax:+39-51-259407 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: G351 name_2: BO405 descr_1: D,201 pos_1: RA = 00H 49M 39.78S +/- 0.1S, pos_2: DEC = +41D 35' 29.4" +/- 1", pos_3: PLATE-ID = 01JV equinox: 2000 comment_1: FLUX1= CLUSTER INTEGRATED V comment_2: FOR ACQ ONLY comment_3: FLUX2= HB STAR FOR TIME EXP. fluxnum_1: 1 fluxval_1: V=15.16 +/- 0.1, B-V=0.72 fluxnum_2: 2 fluxval_2: V=25.0 +/- 0.1, TYPE=F0V, E(B-V)=0.10 ! targnum: 2 name_1: G280 name_2: BO225 descr_1: D,201 pos_1: RA = 00H 44M 29.51S +/- 0.1S, pos_2: DEC = +41D 21' 35.48" +/- 1", pos_3: PLATE-ID = 01JV equinox: 2000 comment_1: FLUX1= CLUSTER INTEGRATED V comment_2: FOR ACQ ONLY comment_3: FLUX2= HB STAR FOR TIME EXP. fluxnum_1: 1 fluxval_1: V=14.26 +/- 0.1, B-V=0.92 fluxnum_2: 2 fluxval_2: V=25.0 +/- 0.1, TYPE=F0V, E(B-V)=0.10 ! ! end of fixed targets ! No solar system records found generic_targets: targnum_1: 5 name_1: G351-FIELD name_2: BO405-FIELD descr_1: E,301,911 criteria_1: RA = 00H 49M 39.78S, criteria_2: DEC = +41D 35' 29.42", R = 4.55' comment_1: ANY PARALLEL WFPC2 FIELD WHEN, comment_2: FOC/96 IS POINTING ON G351 fluxnum_1: 1 fluxval_1: V=25.0 +/- 0.1, TYPE=F0V, E(B-V)=0.10 ! targnum_1: 6 name_1: G272 name_2: BO218-FIELD descr_1: E,301,911 criteria_1: RA = 00H 44M 14.27S, criteria_2: DEC = +41D 19' 19.09", R = 4.55' comment_1: PARALLEL WFPC2 FIELD WHEN FOC/96 IS fluxnum_1: 1 fluxval_1: V=14.83 +/- 0.1,TYPE=F0V, E(B-V)=0.10 ! ! end of generic targets exposure_logsheet: linenum: 1.000 targname: G351 config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F430W num_exp: 1 time_per_exp: 3800S s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: CYCLE 4 ! linenum: 2.000 targname: G351 config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F480LP num_exp: 1 time_per_exp: 10800S s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: CYCLE 4 ! linenum: 3.000 targname: G351-FIELD config: WFPC2 opmode: IMAGE aperture: WFALL-FIX sp_element: F555W num_exp: 1 time_per_exp: 3800S s_to_n: 10 fluxnum_1: 1 priority: 2 req_1: PAR; CYCLE 4 comment_1: PARALLEL WITH 1 ! linenum: 4.000 targname: G351-FIELD config: WFPC2 opmode: IMAGE aperture: WFALL-FIX sp_element: F814W num_exp: 1 time_per_exp: 10800S s_to_n: 10 fluxnum_1: 1 priority: 2 req_1: PAR; CYCLE 4 comment_1: PARALLEL WITH 2 ! linenum: 5.000 targname: G280 config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F430W num_exp: 1 time_per_exp: 3800S s_to_n: 10 fluxnum_1: 2 priority: 1 ! linenum: 6.000 targname: G280 config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F480LP num_exp: 1 time_per_exp: 10800S s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: CYCLE 4 ! linenum: 7.000 targname: G272 config: WFPC2 opmode: IMAGE aperture: WFALL-FIX sp_element: F555W num_exp: 1 time_per_exp: 3800S s_to_n: 10 fluxnum_1: 1 priority: 2 req_1: PAR; CYCLE 4 comment_1: PARALLEL WITH 5 ! linenum: 8.000 targname: G272 config: WFPC2 opmode: IMAGE aperture: WFALL-FIX sp_element: F814W num_exp: 1 time_per_exp: 10800S s_to_n: 10 fluxnum_1: 1 priority: 2 req_1: PAR; CYCLE 4 comment_1: PARALLEL WITH 6 ! ! end of exposure logsheet ! No scan data records found