5909( 0) - 07/18/95 18:35 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5909 Version: ********** Check-in Date: ********** 1.Proposal Title: Complete Ionization Mapping of Cygnus A ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Neal Jackson NRAL Jodrell Bank CoI: Clive Tadhunter Sheffield University N CoI: Martin Shaw Sheffield University N CoI: George Miley Leiden Observatory N CoI: William Sparks STScI N CoI: Duccio Macchetto STScI N ------------------------------------------------------------------------------------ 6. Abstract We propose the most detailed imaging study yet undertaken of a wide range of lines in the prototypical radio galaxy Cygnus A. Lines of ionization states from OI to OIII will be investigated and correlated in detail with each other and with the radio structure. The data will allow us to investigate the physical mechanisms operating in each separate part of the source and hence to disentangle the influences of nuclear photoionization and shocks induced by the passage of the radio jet. The data will also allow us to clarify the current confusion regarding the possible nitrogen overabundance. Since all the phenomena occur within a radius of 0.5" this is not possible from the ground: we know from previous investigations that clumping takes place on scales (0.1--0.2 arcsecond) that are only accessible to the HST. Our ultimate goal will be to determine what parts of the extended line and continuum emission have their origins in photoionization by a hidden nucleus (quantifying the degree of anisotropy with which this nucleus emits) and what parts are shock excited (determining with unprecedented clarity the physical conditions in the shocks). ------------------------------------------------------------------------------------ 5909( 0) - 07/18/95 18:35 - [ 2] Observations Description ------------------------ We calculate the expected flux in the weakest line, OI. The magnitude of the continuum in V in the central 4" (roughly the extent of the emission lines) is about 16.3. In the ramp filter (assuming a bandwidth of 80Angstrom , cf figure 3.3 of the WFPC2 Handbook and an efficiency 30\ less than that of the 673N filter) we will obtain about 100 continuum counts per second within this area (using equation 6.1. of the WFPC2 Handbook). The equivalent width of the line is about 50Angstrom , hence we will obtain 60 line counts per second. We expect the bulk of the line counts to be distributed within regions totalling a few square arcseconds, so the ``astrophysically interesting'' pixels will contain about 0.3 continuum and 0.2 line counts per second. The corresponding continuum image to be subtracted will have a bandwidth about 10 times bigger and therefore about 3 counts per second. Integration times of 30 minutes in the line filter will therefore give S:N in the line per pixel of 360/SQRT((540+360) = 12 per pixel. 2 orbits are therefore necessary for a good (S:N 20) image of OI and 1 orbit will be used for the other, stronger lines. Real Time Justification ----------------------- The authors are engaged in a programme of study of Cygnus A with ground based telescopes. CNT and MS have extensive new spectroscopic data taken with the William Herschel Telescope which is just published or in press. NJ and CNT have new blue spectropolarimetric data to constrain the nature of Cygnus A's blue extended continuum emission which was taken last month an is now being analysed. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5909( 0) - 07/18/95 18:35 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 3C405 GALAXY RA=19H 59M 28.34S +/- 0.01S, J2000 Z=0.057 V=16.3 DEC=40D 44' 2.2" +/- 0.1" B-V=0.7 5909( 0) - 07/18/95 18:35 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 3C405 WFPC2 IMAGE LRF LRF 3937 1 2300S ------------------------------------------------------------------------------------------------------------------------------------ 13 3C405 WFPC2 IMAGE LRF LRF 3937 1 1100S ------------------------------------------------------------------------------------------------------------------------------------ 40 3C405 WFPC2 IMAGE LRF LRF 3937 1 1200S ------------------------------------------------------------------------------------------------------------------------------------ 42 3C405 WFPC2 IMAGE LRF LRF 3937 1 1000S ------------------------------------------------------------------------------------------------------------------------------------ 43 3C405 WFPC2 IMAGE PC1 F814W 1 1000S ------------------------------------------------------------------------------------------------------------------------------------ 50 3C405 WFPC2 IMAGE LRF LRF 6657 1 2500S ------------------------------------------------------------------------------------------------------------------------------------ 53 3C405 WFPC2 IMAGE LRF LRF 6657 1 1000S ------------------------------------------------------------------------------------------------------------------------------------ 70 3C405 WFPC2 IMAGE PC1 F336W 1 1000S ------------------------------------------------------------------------------------------------------------------------------------ 77 3C405 WFPC2 IMAGE PC1 F336W 1 1100S ------------------------------------------------------------------------------------------------------------------------------------ 80 3C405 WFPC2 IMAGE LRF LRF 6934 1 1100S ------------------------------------------------------------------------------------------------------------------------------------ 5909( 0) - 07/18/95 18:35 - [ 5] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 90 3C405 WFPC2 IMAGE LRF LRF 5290 CR-SPLIT=NO 1 400S ------------------------------------------------------------------------------------------------------------------------------------ 91 3C405 WFPC2 IMAGE LRF LRF 5290 CR-SPLIT=NO 1 400S ------------------------------------------------------------------------------------------------------------------------------------ 92 3C405 WFPC2 IMAGE LRF LRF 5290 CR-SPLIT=NO 1 500S ------------------------------------------------------------------------------------------------------------------------------------ 95 3C405 WFPC2 IMAGE LRF LRF 6934 1 400S ------------------------------------------------------------------------------------------------------------------------------------ 5909( 0) - 07/18/95 18:35 - [ 6] Summary Form for Proposal 5909 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements LRF F814W F336W ------------------------------------------------------------------------------------------------------------------------------------ Target Names 3C405 ------------------------------------------------------------------------------------------------------------------------------------