! Proposal 5914, submission 1 ! PI: Ata Sarajedini ! Received Tue Mar 14 22:30:27 EST 1995 ! From: ata@noao.edu ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5914,v 2.1 1995/03/27 15:11:41 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Marc Bremmer ! Phone: 410 338-4458 , E-mail: bremmer@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Sat Dec 17 10:13:20 EST 1994 ! Proposal_Information ! Section 4 Title: The Formation History of Globular Clusters in M33 Proposal_Category: GO Scientific_Category: Stellar Populations Cycle: 5 Investigators PI_name: Ata Sarajedini PI_Institution: Kitt Peak National Observatory CoI_Name: Doug Geisler CoI_Institution: Cerro Tololo Inter-American Obs. Contact: ! Y or N (designate at most one contact) CoI_Name: Robert Schommer CoI_Institution: Cerro Tololo Inter-American Obs. Contact: ! Y or N (designate at most one contact) CoI_Name: Paul Harding CoI_Institution: Steward Observatory Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We propose to study the early formation history of M33 by investigating the nature of the ``second parameter'' phenomenon among its globular star clusters. Discovered among the globular clusters of the Milky Way more than 30 years ago, the ``second parameter'' effect describes the degeneracy in the behavior of horizontal branch morphology with metal abundance. This degeneracy implies the existence of a second parameter, which, in addition to metal abundance, influences the morphology of the horizontal branch. Our approach involves the construction of (V,V-I) color-magnitude diagrams for a number of M33 clusters selected to be analogs of globular clusters in the Galaxy. From these diagrams, we will measure the cluster metallicity and horizontal branch morphology in order to look for a range of horizontal branch types at a given metal abundance and thus determine the presence and nature of any second parameter effect. A knowledge of both the metallicities and HB morphologies of the globulars in M33 will provide important constraints on their formation and evolution as well as that of the galaxy. Furthermore, when these data are combined with similar data for the globular clusters in M31, the Large and Small Magellanic Clouds, and the Fornax dwarf spheroidal galaxy, we will have the opportunity to probe the evolutionary history of these galaxies and how it varies with mass and morphological type. Questions ! Free format text (please update) Observing_Description: M33 is at (m-M)_V ~ 24.8 implying that the horizontal branch (HB) stars of a typical M33 cluster are at V ~ 25.6. The following signal-to-noise calculations are based on information provided in the WFPC2 manual. With the F555W filter, a 5000 sec. exposure will yield signal-to-noise (S/N) ~ 25 at V=25.6. With the F814W filter, 5000 sec. will yield S/N~20 at I=25.6. The stars that comprise the target clusters are on average ~ 1 magnitude brighter in the I filter as compared with the V filter, so an exposure time of 5000 sec. will yield S/N~28 at I=24.6. Given its declination, M33 will be observable for 53 minutes during each HST orbit. Thus, for each visit, the first orbit will consist of 720 sec for guide star acquisition + 2200 sec CR-SPLIT F555W exposure + 120 sec CR-SPLIT overhead. A small offset will occur during Earth occultation. The next orbit will consist of 360 sec for guide star re-acquisition + 2700s F555W exposure + 120 sec CR-SPLIT overhead, with the small offset again occurring during Earth occultation. The third orbit and fourth orbit are identical to the second. Thus, each target cluster requires 4 orbits. Real_Time_Justification: Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: NGC598-U49 Alternate_Names: Description: EXT-CLUSTER Position: RA=01H 33M 45.01S +/- 0.013S, DEC=+30D 47' 46.8" +/- 0.15" ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: J2000 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V = 16.25, B-V = 0.68 ! Include at least V and B-V Comments: Solar_System_Targets ! Section 5.2 Target_Number: Target_Name: Description: Level_1: ! Satellite of Sun Level_2: ! Satellite of Level_1 Level_3: ! Satellite of Level_2 Window: Flux: ! Include at least V and B-V Comments: Generic_Targets ! Section 5.3 Target_Number: Target_Name: Description: Criteria: Flux: Comments: Scan_Data ! Appendix B Scan_Number: FGS_Scan: Cont_or_Dwell: Dwell_Points: Dwell_Secs: Scan_Width: Scan_Length: Sides_Angle: Number_Lines: Scan_Rate: First_Line_PA: Scan_Frame: Length_Offset: Width_Offset: ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 01 Visit_Requirements: ORIENT 135.0D TO 270.0D ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN