8283( 4) - 02/12/99 12:59 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8283 Version: 4 Check-in Date: 12-Feb-1999 12:58:46 1.Proposal Title: High Abundances in Luminous Quasars: A Test Case ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Jack Baldwin Cerro Tololo Inter-American Observatory CoI: Dr. Gary Ferland University of Kentucky N CoI: Dr. Fred Hamann University of California -- San Diego N CoI: Dr. Kirk Korista Western Michigan University N ------------------------------------------------------------------------------------ 5. Abstract Recent studies of high-redshift quasars suggest that their broad emission line regions (BELRs) have metallicities (Z) that are generally above solar. A natural conclusion is that quasars are associated with an epoch of very rapid and extensive star formation during the birth of massive galaxies. However, these metallicity estimates rest on just a few emission lines, most notably N V Lambda1240. We have embarked on a study of other BEL metallicity indicators, especially other nitrogen lines. The N IV Lambda1486 and N III Lambda1750 intercombination lines can be useful abundance probes, but are usually too weak to measure. The only other permitted N line, N III Lambda990, should be an excellent diagnostic but its short wavelength make observations difficult. The quasar Q0353--383 is an ideal test case for all these abundance indicators because the intercombination lines are known to be strong (Osmer 1980). We propose HST-STIS observations to measure N III 990 and other emission lines below LyAlpha to complement our ground-based spectra. The combined data set will complete our reconnaissance of the nitrogen spectrum, measure the gas density and constrain the ionization using abundance-independent line ratios. We will compare results from the various abundance diagnostics, and derive a definitive nitrogen abundance from several stages of ionization. ------------------------------------------------------------------------------------ 8283( 4) - 02/12/99 12:59 - [ 2] Observations Description ------------------------ We are observing a V=17.5 point-source QSO. The spectrum will cover the restframe wavelength range 568A - - 1034A. Besides the lines that are the focus of our metallicity studies, this observation might reveal lines such as Ne VIII 770, 780+ O IV 789. We will use STIS with the CCD and grating G230LB. The slit width will be 0.2 arcsec. We checked the possibility of using either grating G230MB, or the echelle mode in order to get higher resolution for better rejection of LyAlpha forest absorption, but the number of orbits required goes up drastically. These lower resolution observations will be adequate to get a general idea of the emission-line strengths, which is all that we need. We need signal:noise ~ 30:1 in order to get at least some information about line blending and whether or not there appears to be blanketing by LyAlpha forest absorption lines. According to the STIS ETC, with an expected continuum flux of f_Lambda > 6 * 10^-16 rmergs/s/cm^2/Angstrom, the 3 orbits which we were awarded will give S:N ~ 30:1 per resolution element. The lines will have roughly 20 resolution elements across the profile. The object acquistion will be done using ACQ. The spectra then will be taken as three exposures, each with CR-SPLIT=2 to let us reject cosmic rays, but with the QSO offset 0.5 arcsec along the slit between exposures in order to let us reject hot/cold pixels. We want to have one exposure per orbit. The first exposure will be shorter than the others. Real Time Justification ----------------------- We will obtain a higher S/N and spectral resolution spectrum of Q0353 spanning the spectral region between O VI 1034 and MgII 2800 with the 4-m CTIO telescope. We will want to coordinate these observations with those of HST to obviate any possibility of source variability. The flux from a QSO broad-lined region might vary significantly on a timescale of several months (much slower than a Seyfert galaxy), so we wish to have the HST and ground-based observations made within approximately 3-4 months of each other. Q0353-353 is accessible in the sky for the ground-based observations only during the period Oct-Nov-Dec, so we want to make our HST observations sometime between August and February. We have requested this using the BETWEEN requirement. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8283( 4) - 02/12/99 12:59 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 Q0353-383 GALAXY, QSO RA=3H 54M 49.84S +/- 0S, DEC = - J2000 V = +17.5 38D 09' 55.56" +/- 0", PLATE- F(3250)=7.6e-16 ID=00AM F(5000)=4.9e-16 8283( 4) - 02/12/99 12:59 - [ 4] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 1-AUG-1999 AND 29-FEB-2000 BETWEEN 1-AUG-2000 AND 28-FEB-2001 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 Q0353-383 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 40 S ONBOARD ACQ FOR 2-4 CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q0353-383 STIS/C ACCUM 52X0.2 G230LB 2375 CR-SPLIT=2 1 38 M CD ------------------------------------------------------------------------------------------------------------------------------------ 3 Q0353-383 STIS/C ACCUM 52X0.2 G230LB 2375 CR-SPLIT=2 1 49 M POSition TARGet 0.0, 0.5 CD ------------------------------------------------------------------------------------------------------------------------------------ 4 Q0353-383 STIS/C ACCUM 52X0.2 G230LB 2375 CR-SPLIT=2 1 49 M POSition TARGet 0.0, 1.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 8283( 4) - 02/12/99 12:59 - [ 5] Summary Form for Proposal 8283 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 1-AUG-1999 AND 29-FEB-2000 BETWEEN 1-AUG-2000 AND 28-FEB-2001 ONBOARD ACQ FOR 2-4 POSition TARGet 0.0, 0.5 POSition TARGet 0.0, 1.0 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G230LB ------------------------------------------------------------------------------------------------------------------------------------ Target Names Q0353-383 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 2375 ------------------------------------------------------------------------------------------------------------------------------------