9376( 2) - 02/08/02 12:53 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9376 Version: 2 Check-in Date: 08-Feb-2002 12:53:05 1.Proposal Title: A Powerful Double Radio Source from a Spiral Galaxy ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: William Keel University of Alabama CoI: Dr. Michael Ledlow Gemini Observatory N CoI: Dr. Frazer Owen NRAO N ------------------------------------------------------------------------------------ 5. Abstract We have identified a powerful double radio source whose host galaxy is clearly a disk system, and probably a spiral. This violates a very general pattern among radio -loud AGN, and understanding this object may thus shed light on the differences among expressions of nuclear activity between spiral and elliptical hosts. We propose a set of images to verify the spiral morphology, seek evidence of a nuclear ionization cone and jet/ISM interactions via narrow-band imaging, and search for optical synchrotron emission from the radio jet. These data would show whether indeed this (already strong) case indeed represents a spiral galaxy producing a powerful double source, what kind of spiral, and how both the nuclear and extended activity compare to those in typical elliptical host systems. ------------------------------------------------------------------------------------ 9376( 2) - 02/08/02 12:53 - [ 2] Observations Description ------------------------ o Wide-band optical imaging. This gets us the morphology of the host galaxy. For H_0=75, 1" corresponds to 1.3 kpc so an ACS WFC pixel subtends 65 pc. Ideally we would like to distinguish between a dusty S0 (S0^+) system and a genuine spiral, so we need to see not only dust lanes (the most prominent of which is identified in ground-based images) but clear spiral structure and bright star-forming regions, if present. We select two bands, which serve as continuum bands for the narrow-band LRF imaging as well. We allow one orbit for this imagery, which will accordingly go quite deep in surface brightness. The typical S/N per resolution element (set by sampling at 0.1") will be 6 in the outer disk, with typical surface brightness Mu_R = 22.5 per square arcsecond, in half-orbit 1300-second CR-split exposure pairs. F555W will serve as continuum for O III, while we will interpolate between F555W and F775W for HAlpha (which is redshifted to 7002 Angstrom). o Narrow-band imaging in O III Lambda 5007 and HAlpha, to seek an ionization cone and jet/ISM interactions. O III emission redshifts to 5342 A, so we use the linear ramp filter (LRF) FR511N. A total line flux 3 * 10^-15 ergs/cm^2 s is present in O III from our slit spectra, with a comparable flux in HAlpha+N II, within which any ionization cone would be included. If this flux were distributed uniformly within a 2" region (as a worst case), the line emission would be detected at S/N=5 (per 0.1" square region) in FR551N after a 2700-second exposure pair. Thus this total exposure should detect substructure clearly (which could only improve the S/N over a uniform disk). Guided by the extent and luminosity of the regions in Centaurus A and 3C 305, similar surface-brightness sensitivity should reach relevant levels. Results in Seyfert galaxies show that the ratio O III/HAlpha is much more diagnostic of ionization cones than the O III morphology by itself, so we request observations in both these lines, at one orbit for each line with the LRF, and using the broad-band images above for continuum subtraction. o Near-UV imaging, for synchrotron emission from the jet. Among the optical jets found among radio galaxies, the typical spectral index between 20 cm and the optical range is Alpha = -0.75. A bright jet will appear in the broadband optical image, but contrast with the background will be improved on going to wavelengths below the 4000-Angstrom\ break in the galaxy spectrum. We don't want to go too short, though, since some jets have spectral breaks in the optical or near-UV. The ACS HRC filter can do this experiment very well, both with regard to image scale and near-UV sensitivity. Taking the M87 jet and scaling it in distance as well as radio flux, the corresponding near-UV emission would have several pointlike knots of flux 5 * 10^- 19 erg/cm^2 s Angstrom\ at 2500 Angstrom\ . A full-orbit 2700-second observation would detect such objects individually at S/N>6 (for 5 * 5-pixel effective aperture). Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9376( 2) - 02/08/02 12:53 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 0313-1917 GALAXY, Radio galaxy, RA=03H 15M 52.1S +/- 0.1S, DEC=- 2000.0 Z=0.067 V = 15.2 spiral, interacting 19D 06' 44.0" +/- 0.5", PLATE-ID B-V = 0.9 galaxy = 014E Coordinate Source: GSC_SURVEY_PLATE 9376( 2) - 02/08/02 12:53 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 320D TO 110D; ORIENT 150D TO 253D On Hold Comments: Additional Comments: ORIENT ranges are designed to keep a companion galaxy in the field for broadband observations and exclude a V=11.8 star. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 0313-1917 ACS/WF ACCUM WFC2 F555W CR-SPLIT=2 1 1100 S C ------------------------------------------------------------------------------------------------------------------------------------ 2 0313-1917 ACS/WF ACCUM WFC2 F775W CR-SPLIT=2 1 1000 S C ------------------------------------------------------------------------------------------------------------------------------------ 3 0313-1917 ACS/WF ACCUM WFC FR551N 5342 CR-SPLIT=2 1 2500 S C ------------------------------------------------------------------------------------------------------------------------------------ 4 0313-1917 ACS/WF ACCUM WFC FR716N 7003 CR-SPLIT=2 1 2500 S C ------------------------------------------------------------------------------------------------------------------------------------ 9376( 2) - 02/08/02 12:53 - [ 5] Visit: 02 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 0313-1917 ACS/HR ACCUM HRC F250W CR-SPLIT=2 1 2600 S C ------------------------------------------------------------------------------------------------------------------------------------ 9376( 2) - 02/08/02 12:53 - [ 6] Summary Form for Proposal 9376 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC2 WFC HRC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 320D TO 110D; ORIENT 150D TO 253D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F775W FR551N FR716N F250W ------------------------------------------------------------------------------------------------------------------------------------ Target Names 0313-1917 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 5342 7003 ------------------------------------------------------------------------------------------------------------------------------------