Proposal_Information

              Title: HST SPECTROSCOPY OF CYGNUS A -II. SPECTROSCOPY
  Proposal_Category: GO
Scientific_Category: QUASARS & AGN,
                     RADIO GALAXIES
              Cycle: 4


Investigators

       PI_name: NEAL JACKSON
PI_Institution: 6870


Abstract:
We propose to obtain spectroscopy of the nucleus and extended line emitting knot of the prototypical
high-power radio galaxy Cygnus A.  Ground based images and spectra have so far failed to provide convincing
explanations for the ionization structure of the line emission or proof for the model in which the continuum
light is due to scattering of a hidden quasar nucleus.  By using the HST resolution to exclude contaminating
continuum-emitting components we will be able to do two things. First, we will be able to search for a broad
Balmer line in the central sources, which would be proof of the existence of a hidden quasar nucleus: only
marginal evidence of this broad component exists from ground-based spectra. Second, we will be able to select
out the high surface brightness condensation in the northwest line-emitting component. This will be examined
to clarify the kinematics, find out if it is the location of the narrow line "moving component" and examine
the excitation mechanism of the emission lines in a clearly defined region rather than the average over the
whole source typically seen in ground based images.


Fixed_Targets

  Target_Number: 1
    Target_Name: 3C405-OFFSET
Alternate_Names: CYGNUS-A-OFFSET
    Description: STAR,
                 COMPOSITE SPECTRAL TYPE
       Position: XI-OFF= -2.989" +/- 1.137",
                 ETA-OFF= 22.609" +/- 0.100",
                 FROM 2
        Equinox: J2000
           Flux: V = 16.5 +/- 0.2
       Comments: OFFSET IS N AND SLIGHTLY W OF THE TARGET NUMBER 2

  Target_Number: 2
    Target_Name: 3C405-NUC
Alternate_Names: CYGNUS-A-NUC
    Description: GALAXY,
                 RADIO GALAXY
       Position: RA=19H 59M 28.313S +/- 0.002S,
                 DEC= 40D 44' 2.36" +/-  0.05"
        Equinox: J2000
        Rv_or_z: Z = 0.0567
           Flux: SURF(V) = 19.0 +/- 0.2,
                 E(B-V) = 7.0 +/- 1.0 E-1
       Comments: V SURFACE BRIGHTNESS BASED ON 12.2 ARCSEC**2 APERTURE OF VAN DEN BERGH, APJ 210 L63. DISTRN
                 OF E(B-V) COMPLEX AND VARIES OVER SOURCE.

  Target_Number: 3
    Target_Name: 3C405-NW
Alternate_Names: CYGNUS-A-NW
    Description: GALAXY,
                 RADIO GALAXY
       Position: XI-OFF= -0.887" +/- 1.137",
                 ETA-OFF= 0.516" +/- 0.100",
                 FROM 2
        Equinox: J2000
        Rv_or_z: Z = 0.0567
           Flux: SURF(V) = 20.3 +/- 0.2,
                 SURF(R) = 19.1 +/- 0.2,
                 F-LINE(3727.0) = 6.0 +/- 1.0 E-15
       Comments: SURFACE BRIGHTNESSES BASED ON VESTERGAARD & BARTHEL AJ 105 456 3727 FLUX IS IN CENTRAL KNOT
                 VISIBLE IN OUR FOC OBSERVATION 5007 LINE SHOULD BE AT LEAST 3X AS BRIGHT AS OII


Visits

Visit_Number: 1

   ! From Line 1
     Exposure_number: 10
         Target_Name: 3C405-OFFSET
              Config: FOS/RD
              Opmode: ACQ/PEAK
            Aperture: 4.3
          Sp_Element: G570H
 Optional_Parameters: SEARCH-SIZE-Y=3,
                      SEARCH-SIZE-X=1,
                      SCAN-STEP-Y=0.123
Number_of_iterations: 1
   Time_Per_Exposure: 5S
Special_Requirements: ONBOARD ACQ FOR 15

     Exposure_number: 15
         Target_Name: 3C405-OFFSET
              Config: FOS/RD
              Opmode: ACQ/PEAK
            Aperture: 1.0
          Sp_Element: G570H
 Optional_Parameters: SEARCH-SIZE-Y=2,
                      SEARCH-SIZE-X=6,
                      SCAN-STEP-Y=0.61,
                      SCAN-STEP-X=0.61
Number_of_iterations: 1
   Time_Per_Exposure: 5S
Special_Requirements: ONBOARD ACQ FOR 20

   ! From Line 2
     Exposure_number: 20
         Target_Name: 3C405-OFFSET
              Config: FOS/RD
              Opmode: ACQ/PEAK
            Aperture: 0.5
          Sp_Element: G570H
 Optional_Parameters: SEARCH-SIZE-Y=3,
                      SEARCH-SIZE-X=3,
                      SCAN-STEP-Y=0.29,
                      SCAN-STEP-X=0.29
Number_of_iterations: 1
   Time_Per_Exposure: 5S
Special_Requirements: ONBOARD ACQ FOR 25

     Exposure_number: 25
         Target_Name: 3C405-OFFSET
              Config: FOS/RD
              Opmode: ACQ/PEAK
            Aperture: 0.3
          Sp_Element: G570H
 Optional_Parameters: SEARCH-SIZE-Y=3,
                      SEARCH-SIZE-X=3,
                      SCAN-STEP-Y=0.17,
                      SCAN-STEP-X=0.17
Number_of_iterations: 1
   Time_Per_Exposure: 5S
Special_Requirements: ONBOARD ACQ FOR 30

   ! From Line 3
     Exposure_number: 30
         Target_Name: 3C405-OFFSET
              Config: FOS/RD
              Opmode: ACQ/PEAK
            Aperture: 0.3
          Sp_Element: G570H
 Optional_Parameters: SEARCH-SIZE-Y=5,
                      SEARCH-SIZE-X=5,
                      SCAN-STEP-Y=0.052,
                      SCAN-STEP-X=0.052
Number_of_iterations: 1
   Time_Per_Exposure: 20S
Special_Requirements: ONBOARD ACQ FOR 40-60
            Comments: EXP TIMES ARE FOR CRITICAL PEAKUP ON STAR OF 16.5MAG. AFTER PEAKUP SLEW DIRECTLY TO
                      TARGET USING OFFSETS GIVEN

   ! From Line 4
     Exposure_number: 40
         Target_Name: 3C405-NUC
              Config: FOS/RD
              Opmode: ACCUM
            Aperture: 0.3
          Sp_Element: G570H
          Wavelength: 4571.0-6820.0
Number_of_iterations: 1
   Time_Per_Exposure: 5660S
            Comments: S-N CTM/DIODE FOR 0.3" APT APPLIED TO FOC IMAGE. LINES >100A EQ.W.

   ! From Line 5
     Exposure_number: 50
         Target_Name: 3C405-NUC
              Config: FOS/RD
              Opmode: ACCUM
            Aperture: 0.3
          Sp_Element: G780H
          Wavelength: 6272.0-9219.0
Number_of_iterations: 1
   Time_Per_Exposure: 3860S
            Comments: AFTER THIS EXPOSURE SLEW TO TARGET IN LINENUM 6 USING OFFSETS GIVEN IN TARGET LISTS

   ! From Line 6
     Exposure_number: 60
         Target_Name: 3C405-NW
              Config: FOS/RD
              Opmode: ACCUM
            Aperture: 0.3
          Sp_Element: G570H
          Wavelength: 4571.0-6820.0
Number_of_iterations: 1
   Time_Per_Exposure: 3860S
            Comments: S-N BASED ON 0.3" APERTURE APPLIED TO FOC IMAGE.


Data_Distribution

         Medium: 8MM
Blocking_Factor: 10
        Ship_To: PI_Address
       Ship_Via: UPS