! Proposal 5956, submission 2 ! PI: William Sparks ! Received Tue Jan 30 10:55:17 EST 1996 ! From: rij@stsci.edu ! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /focd/data1/rij/5956.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Fri Jan 26 18:07:51 EST 1996 Proposal_Information Title: Mergers or Cooling Flows: the Nature of NGC4696 Proposal_Category: GO Scientific_Category: Galaxies & Clusters Cycle: 5 Investigators PI_Name: William Sparks PI_Institution: Space Telescope Science Institute CoI_Name: Ferdinando Macchetto CoI_Institution: Space Telescope Science Institute Contact: N CoI_Name: Robert Jedrzejewski CoI_Institution: Space Telescope Science Institute Contact: Y CoI_Name: Daniel Golombek CoI_Institution: Space Telescope Science Institute Contact: N CoI_Name: Marcella Carollo CoI_Institution: Sterrewacht, Leiden Contact: N Abstract: NGC4696, the central dominant galaxy in the Centaurus Cluster, is the key object in the controversy between cooling-flows and mergers. Do cooling-flows cause optical emission filaments in X--ray clusters, and do they dominate the physics of that environment, or are mergers responsible, thereby explaining the dustiness of the filaments and failure to detect `cooling' material? Pre-refurbishment FOC images show the nucleus of NGC4696 is double, with components separated by 0.26 arcsec. We propose to obtain FOS spectroscopy and WFPC2 images that would, if this is a genuine double nucleus, to all intents and purposes prove that the galaxy has undergone a recent merger. We will obtain quantitative information on the distribution of the gas, dust and stars in this archetypal galaxy at physically interesting length scales. Questions Observing_Description: For the FOS target acquisition, we would perform an offset from a nearby star: binary search plus peakup on the star, then an (accurate) offset to the positions of each of the nuclei. (This process requires exactly one orbit of overhead only, and is the reason why the first spectrum in the observation summary form has an extra orbit of time.) The individual nuclei fluxes, as measured from the FOC images, have F_Lambda~ 8* 10^-18erg.s.^-1.cm^-2.Angstrom ^-1. The separation of the nuclei is only 0.26 arcsec and so HST spatial resolution is essential to obtain spectra of these two nuclei separately. (We have taken ground based work to the limit, and have already shown that there is kinematic substructure present, Carollo 1993.) We propose to use the FOS 0.3 arcsec aperture. For exposures of three orbits duration, 2500 s per orbit, using the FOS plus G570H grating, we estimate a continuum signal to noise per diode of between six and nine in each of the spectra. This will be adequate to determine the relative velocities of the two using standard cross-correlation techniques, and it will also be possible to measure individual absorption line indices, including NaD and Mgb. For WFPC2 imaging, we wish to obtain short exposures in V (F555W) and R (F702W), of order 5 min. duration each using the PC. These will serve as essential Early Acquisition Images to carry out the spectrographic acquisition above, and will provide excellent scientific data in their own right. We also require an image taken in the light of NII Lambda 6584Angstrom\\ (which is three times stronger than HAlpha) for which we will use the appropriate LRF filter. The corresponding field of view is 13 arcsec which covers the entire nuclear region and about half of the emission filament system. The V and R images will serve to enable correct continuum subtraction, with proper allowance for color effects introduced by the presence of dust. Typical emission line surface brightnesses are ~ 6.5* 10^-16erg.s.^- 1.cm^-2.arcsec^-2 which translates for an 1800 sec exposure to a S/N of 20 per WFC pixel. The complete imaging part of the proposal requires one orbit. Real_Time_Justification: Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: NGC4696 Alternate_Names: Description: Galaxy, elliptical, nucleus Position: RA=12H 48M 49.2S +/- 1S,DEC=-41D 18' 39.8" +/- 1" Equinox: 2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 20 Comments: Flux is approximate nucleus flux Target_Number: 2 Target_Name: NGC4696-NUC1 Alternate_Names: Description: Galaxy, Nucleus Position: RA=12H 48M 49.2S +/- 1S,DEC=-41D 18' 39.8" +/- 1" Equinox: 2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 20 Comments: Flux is approximate nucleus flux Target_Number: 3 Target_Name: NGC4696-NUC2 Alternate_Names: Description: Galaxy, Nucleus Position: RA-OFF=-0.012S+/- 0.001S,DEC-OFF=0.24"+/- 0.01",FROM 2 Equinox: 2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 20 Comments: Flux is approximate nucleus flux Target_Number: 4 Target_Name: NGC4696-PAR Alternate_Names: Description: GALAXY Position: RA=12H 48M 49.3S +/- 1S,DEC=-41D 18' 39.6" +/- 1' Equinox: 2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 20 Comments: Parallel WFPC2 field Target_Number: 5 Target_Name: NGC4696-OFFSET Alternate_Names: Description: STAR Position: RA=12H 48M 49.3S +/- 1S,DEC=-41D 18' 39.6" +/- 1" Equinox: 2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 20 Comments: Offset star from EARLY ACQ image Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: NGC4696 Config: WFPC2 Opmode: IMAGE Aperture: PC1 Sp_Element: F555W Wavelength: 5407 Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 320S Special_Requirements: Comments: Exposure_Number: 3 Target_Name: NGC4696 Config: WFPC2 Opmode: IMAGE Aperture: PC1 Sp_Element: F702W Wavelength: 6895 Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 320S Special_Requirements: Comments: Exposure_Number: 4 Target_Name: NGC4696 Config: WFPC2 Opmode: IMAGE Aperture: LRF Sp_Element: LRF Wavelength: 6640 Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 1200S Special_Requirements: Comments: Visit_Number: 02 Visit_Requirements: On_Hold_Comments: Visit_Comments: ON HOLD removed as early acq update complete Exposure_Number: 20 Target_Name: NGC4696-OFFSET Config: FOS/RD Opmode: ACQ/PEAK Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: SCAN-STEP-X=3.33,SCAN-STEP-Y=1.23,SEARCH-SIZE-X=2,SEARCH-SIZE-Y=6 Number_of_Iterations: 1 Time_Per_Exposure: 2s Special_Requirements: ONBOARD ACQ FOR 21 Comments: Exposure_Number: 21 Target_Name: NGC4696-OFFSET Config: FOS/RD Opmode: ACQ/PEAK Aperture: 1.0 Sp_Element: MIRROR Wavelength: Optional_Parameters: SCAN-STEP-X=0.61,SCAN-STEP-Y=0.61,SEARCH-SIZE-X=6,SEARCH-SIZE-Y=2 Number_of_Iterations: 1 Time_Per_Exposure: 2s Special_Requirements: ONBOARD ACQ FOR 22 Comments: Exposure_Number: 22 Target_Name: NGC4696-OFFSET Config: FOS/RD Opmode: ACQ/PEAK Aperture: 0.5 Sp_Element: MIRROR Wavelength: Optional_Parameters: SCAN-STEP-X=0.29,SCAN-STEP-Y=0.29,SEARCH-SIZE-X=3,SEARCH-SIZE-Y=3 Number_of_Iterations: 1 Time_Per_Exposure: 2s Special_Requirements: ONBOARD ACQ FOR 23 Comments: Exposure_Number: 23 Target_Name: NGC4696-OFFSET Config: FOS/RD Opmode: ACQ/PEAK Aperture: 0.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: SCAN-STEP-X=0.11,SCAN-STEP-Y=0.11,SEARCH-SIZE-X=4,SEARCH-SIZE-Y=4 Number_of_Iterations: 1 Time_Per_Exposure: 20s Special_Requirements: ONBOARD ACQ FOR 24 Comments: Exposure_Number: 24 Target_Name: NGC4696-NUC1 Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 1000s Special_Requirements: expand; max dur 1000% Comments: Exposure_Number: 25 Target_Name: NGC4696-PAR Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F555W Wavelength: 5407 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1000s Special_Requirements: PAR WITH 24 Comments: Exposure_Number: 26 Target_Name: WAVE Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Exposure_Number: 27 Target_Name: NGC4696-NUC1 Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2360s Special_Requirements: Comments: Exposure_Number: 28 Target_Name: NGC4696-PAR Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F555W Wavelength: 5407 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1500s Special_Requirements: PAR WITH 27 Comments: Exposure_Number: 29 Target_Name: WAVE Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Exposure_Number: 30 Target_Name: NGC4696-NUC1 Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2360S Special_Requirements: Comments: Exposure_Number: 31 Target_Name: NGC4696-PAR Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F555W Wavelength: 5407 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1500S Special_Requirements: PAR WITH 30 Comments: Exposure_Number: 32 Target_Name: WAVE Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Exposure_Number: 33 Target_Name: NGC4696-NUC1 Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2360S Special_Requirements: Comments: Exposure_Number: 34 Target_Name: NGC4696-PAR Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F555W Wavelength: 5407 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1500S Special_Requirements: PAR WITH 33 Comments: Exposure_Number: 35 Target_Name: WAVE Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Exposure_Number: 36 Target_Name: NGC4696-NUC2 Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2360S Special_Requirements: Comments: Exposure_Number: 37 Target_Name: NGC4696-PAR Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F814W Wavelength: 7940 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1500S Special_Requirements: PAR WITH 36 Comments: Exposure_Number: 38 Target_Name: WAVE Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Exposure_Number: 39 Target_Name: NGC4696-NUC2 Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2360S Special_Requirements: Comments: Exposure_Number: 40 Target_Name: NGC4696-PAR Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F814W Wavelength: 7490 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1500S Special_Requirements: PAR WITH 39 Comments: Exposure_Number: 41 Target_Name: WAVE Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Data_Distribution ! 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