! Proposal 5903, submission 1 ! PI: Francesco Ferraro ! Received Tue Mar 14 09:42:36 EST 1995 ! From: pi26@stsci.edu ! revised abstract & description of observations---rtr 13March ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5903,v 5.1 1995/11/22 17:14:12 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 09:58:43 EST 1994 ! Proposal_Information ! Section 4 Title: The Origin and Nature of UV Bright Stars in Globular Clusters Proposal_Category: GO Scientific_Category: Stellar Populations Cycle: 5 Investigators PI_name: Francesco Ferraro PI_Institution: Osservatorio Astronomico di Bologna CoI_Name: Ben Dorman CoI_Institution: NASA/GSFC Contact: N (designate at most one contact) CoI_Name: Robert O'Connell CoI_Institution: University of Virginia Contact: N (designate at most one contact) CoI_Name: Robert Rood CoI_Institution: University of Virginia Contact: N (designate at most one contact) CoI_Name: Jonathan Whitney CoI_Institution: University of Virginia Contact: N (designate at most one contact) CoI_Name: Noella da Cruz CoI_Institution: University of Virginia Contact: N (designate at most one contact) CoI_Name: Carla Cacciari CoI_Institution: Osservatorio Astronomico of Bologna Contact: N (designate at most one contact) CoI_Name: Flavio Fusi Pecci CoI_Institution: Osservatorio Astronomico of Bologna Contact: N (designate at most one contact) CoI_Name: Guido De Marchi CoI_Institution: Osservatorio Astronomico of Teramo Contact: N (designate at most one contact) CoI_Name: Francesco Paresce CoI_Institution: STScI Contact: N (designate at most one contact) Abstract: ! Free format text (please update) We have been allocated telescope time to study two globular clusters in optical and UV filters. The clusters, M80 and M13, have blue horizontal-branch (HB) tails extending to V magnitudes equal to or fainter than the main sequence turnoff. The WFPC2 will be used to image the central regions of these clusters in far-UV, mid-UV and near UV broadband filters, and in the V filter to provide a longer baseline. The object of this investigation is twofold: (a) to explore the HB mass distribution in clusters with blue HB tails (BT clusters) and investigate the relationship between the HB mass distribution and the clusters' structural and dynamical properties and (b) to gain further samples of blue straggler stars (BS) in the cores of such clusters. These observations will indiecrtly probe the mass loss process close to the tip of the red giant branch. The bluest stars to be observed are also very similar to the stars that are probably responsible for the UV upturn in elliptical galaxies. The clusters to be observed have different surface brightness profiles but very similar HB morphology. The near- and mid-UV images will be able to detect blue stragglers in the cluster cores, the production of which is also likely to be related to dynamical processes within the clusters. Questions ! Free format text (please update) Observing_Description: We will image fields in the cluster centers in the F160BW, F255W, and F336W ultraviolet passbands. A short exposure in the Visual band F555W is also required to provide a long wavelength baseline for the HB observations and to allow the calculation of integrated 16 -V and 25-V colors. Short exposures in the B band (F439W) have also been requested for both clusters, which will facilitate comparisons between our results and previous ground-based work. The V observations will also allow the detection of spurious cool sources arising from the redleak in the F336W passband. From 15 or so possible targets known from previous satellite missions to be bright in integrated UV light we have been approved time for 2 clusters with similar metallicity (Fe/H ~ -1.5). NGC 6093 (= M80) (E(B-V)=0.20, V_0( HB) ~ 15.20) is very blue according to ANS observations, although there is reason to suspect the exact value of the UV colors. M80 is interesting because it does not show the color gradients seen in similar clusters. Our observations will show whether it does indeed provide a counterexample to the relationship between the existence of a BT and the production of core BSS. NGC 6205 (= M13) (E(B-V)=0.02, V_0( HB) ~ 14.90) has optical HB morphology that is virtually identical to M80, but its concentration is somewhat lower and it is rather oblate in shape. Complementary observations suggest a bimodal distribution in rotation. Intercomparison between the two clusters and with dense core clusters observed in other HST programs should clarify how dynamical properties affect stellar populations. The exposure times have been calculated in order to reach approximately S/N=10 at V ~ V_0( HB)+5.5 mag in the bands F160BW and F255W for a B0 star (corresponding to an EHB star at the faint end of the BT), and 1 mag below the turnoff in the bands F336W and F555W for a G0 star (for a proper detection and photometry of the BSS which can be found at the turnoff luminosity level). The parameters used for the S/N (or exposure time) calculation are those specified in the WFPC2 Handbook, Version 2.0 May 1994 with the algorithm (S/N)^2=I^2/(I+B) since our observations are not background- dominated. The signal I has been convolved with the PSF over a 3 by 3 pixel region from Tab. 5.1 and 5.2 of the Handbook, and correspondingly the background B has been considered over a 9 pixel square area. All exposures will be split into 4 separate images, shifted by 1 pixel, for the twofold purpose of (1) mapping the PSF for a better photometric accuracy, and (2) avoiding the blooming in the V images (no blooming is expected in the ultraviolet bands). Real_Time_Justification: DO WE NEED THIS?? The flight of Astro-2 containing the Ultraviolet Imaging Telescope (UIT) was launched on 3rd March 1995. It is scheduled to observe NGC 6205. Its observations will provide supporting data for the outer regions of the cluster not seriously affected by the crowding issues in the center. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number:1 Target_Name: NGC6093 Alternate_Names: M80 Description: STELLAR CLUSTER, GLOBULAR CLUSTER Position: RA=16H 17M 2.5S +/- 0.1S, DEC=-22D 58' 30.0" +/- 1" Equinox: 2000 Flux: SURF(V)=15.38 +/- 0.1, E(B-V)=0.20 Comments: Above flux value refers to the central magnitude of the cluster, for ACQ purpose only. For individual stars see observing description. Target_Number:2 Target_Name: NGC6205 Alternate_Names: M13 Description: STELLAR CLUSTER, GLOBULAR CLUSTER Position: RA=16H 41M 41.5S +/- 0.1S, DEC=+36D 27' 37.0" +/- 1" Equinox: 2000 Flux: SURF(V)=16.77 +/- 0.1, E(B-V)=0.02 Comments: Above flux value refers to the central magnitude of the cluster, for ACQ purpose only. For individual stars see observing description. ! 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: ! Section 7.1 On_Hold_Comments: Visit_Comments: ! Section 6.5 Exposure_Number:1 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F160BW Wavelength: Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:2000S Special_Requirements: Exposure_Number:2 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F439W Wavelength: Optional_Parameters:ATD-GAIN=15 Number_of_Iterations:1 Time_Per_Exposure:30S Special_Requirements: END ORBIT Exposure_Number:3 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F439W Wavelength: Optional_Parameters:ATD-GAIN=15 Number_of_Iterations:1 Time_Per_Exposure:30S Special_Requirements: Exposure_Number:4 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F336W Wavelength: Optional_Parameters:ATD-GAIN=15 Number_of_Iterations:1 Time_Per_Exposure:1200S Special_Requirements: Exposure_Number:5 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F255W Wavelength: Optional_Parameters:CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:600S Special_Requirements: Exposure_Number:6 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F555W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:50S Special_Requirements: Exposure_Number:7 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F555W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:4S Special_Requirements: Exposure_Number:8 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F160BW Wavelength: Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:2000S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:9 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F336W Wavelength: Optional_Parameters:ATD-GAIN=15 Number_of_Iterations:1 Time_Per_Exposure:1200S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:10 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F555W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:50S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:11 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F255W Wavelength: Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:300S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:12 Target_Name:NGC6093 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F255W Wavelength: Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:300S Special_Requirements:POS TARG 0.467, 0.467 Visit_Number: 02 Visit_Requirements: ! Section 7.1 Exposure_Number:1 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F255W Wavelength: Optional_Parameters:CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:100S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:2 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F555W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:16S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:3 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F160BW Wavelength: Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:300S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:4 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F160BW Wavelength: Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:300S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:5 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F336W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:300S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:6 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F555W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:2S Special_Requirements:POS TARG 0.467, 0.467 Exposure_Number:7 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F555W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:16S Special_Requirements: Exposure_Number:8 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F160BW Wavelength: Optional_Parameters:CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:600S Special_Requirements: Exposure_Number:9 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F255W Wavelength: Optional_Parameters:CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:100S Special_Requirements: Exposure_Number:10 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F336W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:300S Special_Requirements: Exposure_Number:11 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F555W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:2S Special_Requirements: Exposure_Number:12 Target_Name:NGC6205 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F439W Wavelength: Optional_Parameters:ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations:1 Time_Per_Exposure:30S Special_Requirements:END ORBIT Comments: Data_Distribution ! 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