9365( 2) - 02/07/02 07:02 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9365 Version: 2 Check-in Date: 07-Feb-2002 07:01:38 1.Proposal Title: Spectroscopy in the Inner Region of the 3C 48 Host Galaxy ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Alan Stockton University of Hawaii CoI: Dr Gabriela Canalizo Lawrence Livermore National Laboratory N ------------------------------------------------------------------------------------ 5. Abstract As far as we are aware, there is only one host galaxy continuum feature in a luminous QSO that is bright enough for practical STIS spectroscopy: this is the bright peak ~1" NE of the well-known quasar 3C 48. This feature (3C 48A) is enigmatic, with an apparently distorted morphology. It may be the distended nuclear region of one of the galaxies in this major merger. It might, instead, possibly be the result of interaction of the compact-steep spectrum radio jet with ambient material; but this seems unlikely because the correspondence between the radio and optical morphologies is not very good. We also know from ground-based and HST imaging that 3C 48A is overwhelmingly dominated by continuum radiation, not line emission, and the colors seem to be inconsistent with stars as young as the probable age of the radio jet. Our previous high S/N ground-based spectroscopy of 3C 48 covered most regions of host galaxy beyond ~2"\ from the QSO. From this spectroscopy and spectral synthesis models, we have been able to determine mean ages for recent starbursts in various parts of the host galaxy as well as the velocity field of the stars. By tying the proposed STIS spectroscopy of 3C 48A to our existing spectroscopy of the host galaxy, together with archival PC images, we expect to be able to determine the nature of this unusual inner structure and its role in the evolutionary history of 3C 48. ------------------------------------------------------------------------------------ 9365( 2) - 02/07/02 07:02 - [ 2] Observations Description ------------------------ We will use a 0\farcs5 slit to cover most of 3C\, 48A. We will acquire 3C\, 48 and then offset to the region of interest; we do not need to do a peak up (ACQ/PEAK). From an analysis of the PC images from the HST archive, we find the minimum surface brightness of features in the regions of interest of ~1.0 X 10^ -17 erg/cm^2/s/A/arcsec^2 at 5550 A. We will use the G430L grating. Our main spectral region of interest extends from 4000 to 5700 A in the observed frame. Since we are well oversampled with the 0.5 arcsec slit, we will bin by 2 pixels in the dispersion direction. We will use the 1 count per e$^-$ gain. Using the WWW STIS Exposure Calculator, and assuming single 2400 s exposures in each orbit, we can achieve a S/N of 10 (per 10-binned-pixel resolution element [i.e., 20 unbinned pixels]) in 8 orbits. This is sufficient to allow the fitting of stellar synthesis models averaged over the region of interest and even to look for some variation in the brighter subregions. If the spectrum follows the trend seen in the rest of the 3C\, 48 host galaxy, the Balmer absorption should be strong enough for us to obtain velocities to compare with our Keck results. Finally, although this region does not have exceptionally strong emission lines (based on our ground-based narrow-band imaging), we will almost inevitably pick up some extended emission and be able to map out the velocity field along several arcsec of the slit. Although we estimate that light from the wings of the PSF of the quasar will contribute < 10% of the flux in our aperture, we will also spend a few minutes obtaining the spectrum of the quasar itself with the same grating configuration, in order to be able to subtract off any scattered nuclear component. These observations will take only a small amount of time and can be worked in at the end of one or more orbits. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9365( 2) - 02/07/02 07:02 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 3C48 GALAXY, QUASAR RA=01H 37M 41.28S +/- 0.05S, J2000 Z=0.369 V = 16.2 DEC=+33D 09' 34.17" +/- 1.0", B-V = 0.42 PLATE-ID=00DV Coordinate Source: GUIDE_STAR_CATALOG Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.00 0.00 0.0 2 3C48-A GALAXY, QUASAR XI-OFF=0.96" +/- 0.05", ETA- J2000 Z=0.369 SURF(V) = 21.4+/-1.0 OFF=0.5" +/- 0.05", FROM 1 Coordinate Source: OTHER_SOURCE Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.00 0.00 0.0 9365( 2) - 02/07/02 07:02 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 165D TO 185D ORIENT 345D TO 5D On Hold Comments: Additional Comments: The ORIENT requirements given are meant to place the PA of the STIS slit at 130 degrees or 310 degrees, +/- 10 degrees. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 3C48 STIS/C ACQ F28X50L MIRROR 1 10 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2393 S CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2350 S POS TARG 0, 1 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 4 3C48 STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=1,CR-SPLIT=NO 1 300 S POS TARG 0, 1 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 5 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2400 S POS TARG 0, -1 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 6 3C48 STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=1,CR-SPLIT=NO 1 300 S POS TARG 0, -1 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 9365( 2) - 02/07/02 07:02 - [ 5] Visit: 02 Visit Priority: Visit Requirements: SAME ORIENT AS 01 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 3C48 STIS/C ACQ F28X50L MIRROR 1 10 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2393 S POS TARG 0, -2 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2885 S CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 4 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2885 S POS TARG 0, 1 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 5 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2885 S POS TARG 0, -1 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 6 3C48-A STIS/C ACCUM 52X0.5E G430L 4300 BINAXIS1=2,CR-SPLIT=NO 1 2885 S POS TARG 0, -2 CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 9365( 2) - 02/07/02 07:02 - [ 6] Summary Form for Proposal 9365 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.5E1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BINAXIS1=2 CR-SPLIT=NO BINAXIS1=1 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 165D TO 185D ORIENT 345D TO 5D POS TARG 0, 1 POS TARG 0, -1 SAME ORIENT AS 01 POS TARG 0, -2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430L ------------------------------------------------------------------------------------------------------------------------------------ Target Names 3C48 3C48-A ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4300 ------------------------------------------------------------------------------------------------------------------------------------