! Proposal 5902, submission 1 ! PI: Gregory G. Fahlman ! Received Mon Mar 13 20:42:09 EST 1995 ! From: koenig@astro.ubc.ca ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5902,v 2.1 1995/03/14 16:01:48 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 09:57:32 EST 1994 ! Proposal_Information ! Section 4 Title: Color-Magnitude Diagrams and the internal structure of the globular clusters NGC 5694 & NGC 5824 Proposal_Category: GO Scientific_Category: Stellar Populations Cycle: 5 Investigators PI_name: Gregory G. Fahlman PI_Institution: University of British Columbia CoI_Name: Christian H.B. Koenig CoI_Institution: University of British Columbia Contact: Y ! Y or N (designate at most one contact) CoI_Name: Harvey B. Richer CoI_Institution: University of British Columbia Contact: N ! Y or N (designate at most one contact) CoI_Name: Ian Thompson CoI_Institution: The Observatories, Carnegie Institute Washington Contact: N ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) High stellar densities are produced in the cores of globular clusters through dynamical evolution. Recently, it has become clear that the physical characteristics of the stars in such cores can be modified, leading to the appearance of anomalous stellar populations. A study of these populations is important for furthering our understanding of the dynamical evolution of star clusters. The high spatial resolution imaging provided by HST is essential for uncovering and studying these anomalous stars. We propose to use the WFPC2 to make UBV observations of the central regions of two highly concentrated clusters, NGC 5694 and NGC 5824 for the primary purpose of studying the anomalous stellar populations revealed by our ground based images. These show bright, relatively blue quasi-stellar knots in the cluster cores. A large number of bright stars appear to the blue of the AGB/RGB in the cluster CMDs but, due to extreme crowding, we are unable to determine whether blue straggler stars are also present. These two targets are in the outer halo of the galaxy and the proposed HST observations will have a spatial resolution approximately equivalent to the best ground based images of NGC 6397. A secondary goal is to determine the ages for the two clusters through isochrone fitting and by application of differential measurements relative to other clusters of similar metallicity. Questions ! Free format text (please update) Observing_Description: We will observe NGC 5824 and NGC 5694 in the WFPC2 U,B and V (F336W, F459W and F555W) filters. Our exposure times are adjusted to minimize or where possible avoid the detrimental effects of CCD saturation due to bright stars near the cluster center, but still achieve small photometric errors for the faint magnitude ranges necessary to fulfill our scientific goals. The stellar populations in NGC 5694 & NGC 5824 are in the same magnitude range ( V_HB=18.50 and 18.60 respectively), making the following exposure calculations valid for both targets. In U, B and V short exposures of 120 sec, 10 sec and 120 sec respectively are required to image the core of the cluster and the central knots without saturating. The remaining exposures of 5 * 60 sec, 3 * 500 sec and 3 * 400 sec in V,B and U, respectively, are sufficient to limit photometric errors to 0.1 mags in B and V, 2.5 V-mags below the cluster turnoff, and 0.1 mags in U at the turnoff. With the cluster center placed on the PC virtually none of the stars saturating during the longer exposures will be affecting the WF CCDs. Real_Time_Justification: None. We have obtained UBV observations of NGC 5824 and NGC 5694 under arcsecond seeing conditions at Las Campanas. The data is of excellent quality as indicated above and will enable us to calibrate the WFPC2 data. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: NGC5694 Alternate_Names: Description:STELLAR CLUSTER, Globular Cluster, Nucleus, Knot, Undesignated, STAR, Blue Straggler Position: ! Most common specification format is RA=14H 36M 41.60S +/- 2.0S, DEC=-26D 19' 24.9" +/- 2.0", ! PLATE-ID=0000 Equinox: 1950.0 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=14.765,B-V=0.8,U-V=0.4,SURF-BKG(V)=16.5 Comments: Fluxes are upper limits for most luminous object Fixed_Targets ! Section 5.1 Target_Number: 2 Target_Name: NGC5824 Alternate_Names: Description: STELLAR CLUSTER, Globular Cluster, Nucleus, Knot, Undesignated, STAR, Blue Straggler Position: ! Most common specification format is RA=15H 0M 53.75S +/- 2.0S, DEC=-32D 52' 22.6" +/- 2.0", ! PLATE-ID=0000 Equinox: 1950.0 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=14.765,B-V=0.8,U-V=0.4,SURF-BKG(V)=16.5 Comments: Fluxes are upper limits for most luminous objects ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! 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