Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5368 Report Date: 18-Jul-95:17:14 Version: ********** Check-in Date: ********** 1.Proposal Title: HST SPECTROSCOPY OF CYGNUS A -I. EARLY ACQ IMAGING ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID QUASARS & AGN GO Sub Category RADIO GALAXIES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Neal Jackson LEIDEN OBSERVATORY NETHERLAND 31-71-275851 ------------------------------------------------------------------------------------ 7. 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. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 9.83 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5368 PI: Neal Jackson Proposal Title: HST SPECTROSCOPY OF CYGNUS A -I. EARLY ACQ IMAGING ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Neal Jackson 6870 NETHERLANDS William B. Sparks 3470 USA X George K. Miley 6870 NETHERLANDS Clive N. Tadhunter UNIVERSITY OF SHEFFIELD ENGLAND F Macchetto 3470 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Our aim is to obtain spectra of two small regions within the radio galaxy Cygnus A. The first region is very close to the radio core of the object and the second in the northwest optical condensation. Both regions are embedded in complex emission line regions. A WFPC2 exposure is required for accurate location of these two regions and we therefore propose to obtain a 2x25 min early acquisition exposure. Since both regions are strong line emitters we propose to use the F555W filter for maximum efficiency in their location (this includes the very strong redshifted [OIII] 5007 line). The subsequent FOS exposures will be taken using both the G570H and G780H, to cover all important optical lines out to redshifted H alpha/[SII] and to locate blueshifted narrow line components. THIS FILE CONTAINS THE EARLY ACQUISITION EXPOSURES ONLY ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. We have made extensive spectroscopic and spectropolarimetric observations from the ground. These observations cannot give us the spectrum of the near-nuclear region alone, and cannot give uncontaminated spectral information about the major line- emitting component and thus provide a handle on its kinematics and ionization state. In both cases this is because of the degradation by ground- based seeing which allows light unconnected with the regions under study to enter the science aperture. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. An Early Acquisition WFPC2 exposure is needed as the target regions lie in a complex area of extended emission at the core of the galaxy. THIS FILE CONTAINS THE EARLY ACQUISITION EXPOSURES ONLY. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. ------------------------------------------------------------------------------------ 9. Description of previous HST work. As part of the GTO program we obtained HST FOC images of the central region, both in the [OII] line and in the nearby continuum. This shows a "channel" of lower surface brightness emission along the inner part of the radio jet which appears to bisect the NW component and possibly also the SE component, which would indicate the influence of a counterjet. The line emission appears conentrated in two relatively small regions: the core component (which may be part of the nucleus according to some authors) and a region in the NW component to the north of the radio jet. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The reduction will take place at Leiden and STScI. SDAS/IRAF runs at both Leiden and STScI and there is an ample supply of workstation at both institutes. Page 3 ------------------------------------------------------------------------------------ 11. Address Information Name: NEAL JACKSON Category: PI Institution: 6870 Address: STERREWACHT LEIDEN POSTBUS 9513 2300RA LEIDEN City: State: Zip Code: Country: NETHERLANDS Telephone: 31-71-275851 Telex (or e-mail): jackson@strw.LeidenUniv.nl ------------------------------------------------------------------------------------ Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5368 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 3C405 CYGNUS E,315 RA= 19H 57M 44.443S +/- 1950 Z=0.0567 1 SURF(V)=19.0+/-0.2 -A 0.03S, 2 E(B-V)=0.7+/-0.1 DEC=+40D 35' 46.37" +/- 0.3" 3 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. ------------------------------------------------------------------------------------------------------------------------------------ 2 3C405-OFFSET A,132 TBD-EARLY,RA= 19H 57M 1950 Z=0.0567 1 V=16.0+/-0.5 CYGNUS-A- 43.455S +/- 0.06S, OFFSET TBD-EARLY,DEC=+40D 35' 37.71" +/- 0.6" Comments: EXACT OFFSET STAR TBD AFTER EARLY ACQ PC OBSERVATION ------------------------------------------------------------------------------------------------------------------------------------ 3 3C405-NUC E,315 TBD-EARLY,RA= 19H 57M 1950 Z=0.0567 1 SURF(V)=20.3 +/- 0.2 CYGNUS-A-NUC 44.443S +/- 0.06S, 2 SURF(R)=19.1 +/- 0.2 TBD-EARLY,DEC=+40D 35' 3 F-LINE(3727)=6 +/- 1 E-15 46.37" +/- 0.6" 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 ------------------------------------------------------------------------------------------------------------------------------------ 4 3C405-NW E,315 TBD-EARLY,RA= 19H 57M 1950 Z=0.0567 1 SURF(V) = 19.8 +/- 0.4 CYGNUS-A-NW 44.353S +/- 0.06S, 2 SURF(R) = 18.6 +/- 0.4 TBD-EARLY,DEC=+40D 35' 3 F-LINE(3727) = 8+/-3E-15 47.00" +/- 0.6" Comments: V AND R BRIGHTNESSES ARE EXTRAPOLATIONS FROM VESTERGAARD & BARTHEL USING FLUX RATIOS FROM FOC IMAGE: LINE FLUX IS DERIVED FROM OUR FOC IMAGE TOTAL FLUX FROM OII 3727 LINE FROM ALL CPTS OF OUR FOC IMAGE AGREES WITH OSTERBROCK'S ESTIMATE (APJ 197 535) TO FACTOR OF ~2. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5368 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 3C405 WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 2S 1 1 CYCLE 4 ORIENT 120D +/- 60D Comments: ORIENT+180 OK TOO. NB THESE ARE EARLY ACQ EXPOSURES FOR LATER FOS/RD SPECTROSCOPY. S:N IS CNTR PIXELS. ------------------------------------------------------------------------------------------------------------------------------------ 2 3C405 WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 30S 1 1 CYCLE 4 ORIENT 120D +/- 60D Comments: ORIENT+180 OK TOO. NB THESE ARE EARLY ACQ EXPOSURES FOR LATER FOS/RD SPECTROSCOPY. S:N IS CNTR PIXELS. ------------------------------------------------------------------------------------------------------------------------------------ 3 3C405 WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 3 900S 20 1 1 CYCLE 4 ORIENT 120D +/- 60D Comments: ORIENT+180 OK TOO. NB THESE ARE EARLY ACQ EXPOSURES FOR LATER FOS/RD SPECTROSCOPY. S:N IS CNTR PIXELS. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5368 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 9.83 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category QUASARS & AGN ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category RADIO GALAXIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; ORIENT 120D +/- 60D; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names 3C405 CYGNUS-A 3C405-OFFSET CYGNUS-A-OFFSET 3C405-NUC CYGNUS-A-NUC 3C405-NW CYGNUS-A-NW ------------------------------------------------------------------------------------------------------------------------------------