5846( 3) - 09/12/95 11:20 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5846 Version: 3 Check-in Date: ********** 1.Proposal Title: FOS Spectroscopy of the Complex Gaseous Structure in the Nucleus of NGC5252 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle AGN GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Zlatan Tsvetanov Johns Hopkins University CoI: Jon Morse Space Telescope Science Institute Y CoI: Andrew Wilson University of Maryland N CoI: Gerald Cecil University of North Carolina N ------------------------------------------------------------------------------------ 6. Abstract NGC5252 contains one of the most spectacular examples of an ionization cone in a Seyfert galaxy. Extending to several tens of kpc from the nucleus, its axis is nearly aligned with the linear radio feature. Our narrow-band WFPC-2 images from cycle 4 show a complex circumnuclear pattern of line emitting gas, with a nuclear disk-like structure seen edge-on and oriented roughly perpendicular to the radio axis, and several ``spiral'' arms, arcs and other signatures of ISM distributed around the nucleus. We propose to obtain FOS spectra at three points along the putative nuclear disk and one centered on the brightest extranuclear position within the opening angle, but near the edge of the ionization cone. Our main goals are to: (1) measure the kinematics of the nuclear disk from the velocity displacements and profiles of the emission lines on the nucleus and at two adjacent points. This may allow us to estimate the mass encircled in a small volume at the nucleus; (2) use line ratios from a wide wavelength range (combined with ground-based imaging, and long-slit and Fabry-Perot spectroscopy) to study the physical conditions in the line emitting gas, both in the nuclear disk and in the narrow-line emission within the ionization cone. ------------------------------------------------------------------------------------ 5846( 3) - 09/12/95 11:20 - [ 2] Observations Description ------------------------ Selected FOS aperture positions are shown in Fig.\ 1. To estimatine exposures we have used two independent ground-based spectra to calibrate the flux of our WFPC-2 H-alpha+N II\ image. The two calibrations differ by only ~10\ in flux at the proposed FOS positions. Fluxes were then measured from the calibrated image and other emission lines were scaled according to the ratios suggested by the spectra. (1) To study the kinematics of the emission line gas near the nucleus of NGC5252 we propose to take FOS spectra of the three peaks in the nuclear disk seen on our WFPC2 images (Fig.\ 1). We will use the 0\as3 aperture and G570H grating to cover the brightest emission lines - O Iii\ and H-alpha+N II. To assure a common wavelength scale, we will take one or more wavelength calibration spectra. Exposure times are set to secure ~1000 counts in the H- alpha+N II\ line complex and somewhat more in the O Iii\ line. Experience with the analysis of the M87 spectra shows that this will allow us to make accurate velocity measurements and some evaluation of the profile. Without overhead, these times are: 1000 s (POS1), 1200 s (POS2), and 1600 s (POS3). (2) To study physical conditions in the gaseous nuclear disk, we propose to obtain G400H, G270H, and G160L FOS/RD spectra at the position of the central peak. Exposure times are: 1000 s (G400H), 2400 s (G270H) and 2400 s (G160L). Combined with the velocity measurements in (1) we require a total of 5 orbits. (3) To study the dominant energy source in the extended emission-line region, we propose to obtain UV spectra at the brightest off-nucleus position, POS4 in Fig.\ 1. We will use the 0\as86 FOS aperture because spatial resolution is not critical in this case. This will also help in combining the FOS spectra with ground-based data. We will use the G160L and G270H gratings and the FOS/RD detector. As for the nuclear positions, we have measured the H-alpha+N II\ flux from our WFPC-2 image. Exposures are set to detect the primary discriminant, C IV, as weak as 50\ require ~90 min (2 orbits) for the G160L grating at the off-nucleus position. We note that the C IV\ line is redshifted sufficiently to use the more sensitive red detector instead of the blue. Finally, we have tested target acquisition by using a scaled version of our WFPC-2 images and the current binary search FOS simulator. These tests have assured us that we can use an initial star and a two-stage peak-up to acquire the brightest nuclear peak in one orbit. We therefore request a total of 8 orbits. Real Time Justification ----------------------- None. We would like to stress again that our HST observations are strongly complemented by extensive ground-based data. We have already obtained narrow- band imaging, long-slit spectra at several position angles, and a detailed cube of Fabry-Perot [O~III] spectra. To these we will add a deep long-slit spectrum down to the atmospheric UV cut-off which includes our off-nucleus position. This will be combined with the FOS UV spectra to study the relative importance of different ionizing/excitaion processes in the outflowing gas. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5846( 3) - 09/12/95 11:20 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5846( 3) - 09/12/95 11:20 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC5252-POS1 GALAXY, Seyfert, RA=13H 38M 15.82S +/- 0.01S, 2000 V=+6850 V=15.0 +/- 0.2 Lenticular DEC=4D 32' 33.37" +/- 0.1", PLATE-ID=019P Comments: Part of nuclear disk - nucleus 2 NGC5252-POS2 GALAXY, Seyfert, R=0.36", PA=38.9D, FROM 1 2000 V=+6850 Lenticular Comments: Part of nuclear disk - emission-line knot 3 NGC5252-POS3 GALAXY, Seyfert, R=0.31", PA=216.6D, FROM 1 2000 V=+6850 Lenticular Comments: Part of nuclear disk - emission-line knot 4 NGC5252-POS4 GALAXY, Seyfert, R=2.23", PA=314.2D, FROM 1 2000 V=+6850 Lenticular Comments: Extended Emission-Line Region - knot 5846( 3) - 09/12/95 11:20 - [ 5] 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC5252- FOS/RD ACQ/BIN 4.3 MIRROR FAINT=50.0 1 33S ONBOARD ACQ FOR 2 POS1 ARY Comments: Exp. time from FOS simulator and ground-based spectrum. ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC5252- FOS/RD ACQ/PEA 0.5 MIRROR SEARCH-SIZE- 1 10S ONBOARD ACQ FOR 3 POS1 K X=4, SEARCH- SIZE-Y=4, SCAN- STEP-X=0.24, SCAN-STEP- Comments: Y=0.24 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC5252- FOS/RD ACQ/PEA 0.3 MIRROR SEARCH-SIZE- 1 20S ONBOARD ACQ FOR 4 POS1 K X=4, SEARCH- SIZE-Y=4, SCAN- STEP-X=0.09, SCAN-STEP- Comments: Y=0.09 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC5252- FOS/RD ACCUM 0.3 G160L 1 2300S POS1 ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE FOS/RD ACCUM 0.3 G160L 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 6 WAVE FOS/RD ACCUM 0.3 G270H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC5252- FOS/RD ACCUM 0.3 G270H 1 1140S POS1 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC5252- FOS/RD ACCUM 0.3 G400H 1 1000S POS1 ------------------------------------------------------------------------------------------------------------------------------------ 9 WAVE FOS/RD ACCUM 0.3 G400H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 10 WAVE FOS/RD ACCUM 0.3 G570H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC5252- FOS/RD ACCUM 0.3 G570H 1 1000S POS1 ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC5252- FOS/RD ACCUM 0.3 G570H 1 1200S POS2 ------------------------------------------------------------------------------------------------------------------------------------ 13 WAVE FOS/RD ACCUM 0.3 G570H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 14 NGC5252- FOS/RD ACCUM 0.3 G570H 1 1600S POS3 ------------------------------------------------------------------------------------------------------------------------------------ 5846( 3) - 09/12/95 11:20 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 15 NGC5252- FOS/RD ACCUM 0.3 G270H 1 500S POS1 ------------------------------------------------------------------------------------------------------------------------------------ 16 WAVE FOS/RD ACCUM 0.3 G270H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 17 NGC5252- FOS/RD ACCUM 1.0 G270H 1 2340S POS4 ------------------------------------------------------------------------------------------------------------------------------------ 18 WAVE FOS/RD ACCUM 0.3 G270H 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 19 NGC5252- FOS/RD ACCUM 1.0 G160L 1 2300S END ORBIT POS4 ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC5252- FOS/RD ACCUM 1.0 G160L 1 1340S POS4 ------------------------------------------------------------------------------------------------------------------------------------ 21 NGC5252- FOS/RD ACCUM 1.0 G400H 1 1000S POS4 ------------------------------------------------------------------------------------------------------------------------------------ 5846( 3) - 09/12/95 11:20 - [ 7] Summary Form for Proposal 5846 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FAINT=50.0 SCAN-STEP-Y=0.24 SCAN-STEP-Y=0.09 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category AGN ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4 END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G160L G270H G400H G570H ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC5252-POS1 WAVE NGC5252-POS2 NGC5252-POS3 NGC5252-POS4 ------------------------------------------------------------------------------------------------------------------------------------