9413( 4) - 03/04/03 09:32 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9413 Version: 4 Check-in Date: 04-Mar-2003 09:31:26 1.Proposal Title: Infrared Spectroscopy of z > 5 QSOs ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Michael Corbin Computer Sciences Corporation CoI: Dr. Wolfram Freudling Space Telescope - European Coordinating N Facility CoI: Prof. Kirk Korista Western Michigan University N ------------------------------------------------------------------------------------ 5. Abstract The elemental abundances of high-redshift QSOs provide an important probe of the early universe. The ratio of iron to alpha-process elements observed in all QSOs to z ~ 4.5 in particular suggests that the gas has been enriched by Type Ia supernovae. Evidence of such enrichment in turn helps constrain the ages and masses of QSO host galaxies, which can be compared with the predictions of galaxy formation models under currently popular LambdaCDM cosmologies. With these motivations we propose to obtain NICMOS grism spectra of five bright (z^* ~ 19) QSOs from z = 5.03 to z = 6.28 recently discovered in the Sloan Digital Sky Survey. Our main goal will be to measure the strength of the broad Fe II emission complex at 2500 Angstrom (rest) in these very young (~ 1 Gyr) objects, if it is present at all. With the exception of two objects at z = 5.99 and z = 6.28 it will also be possible to measure the Mg II Lambda2800 line. These measurements are impossible from the ground because of the atmospheric absorption bands in the near infrared. The Fe II / Mg II emission ratio will in turn be used to estimate the relative abundance of these elements in the objects, and to compare these abundances to those of QSOs at lower redshifts. The infrared brightness of the objects and reduced sky background will allow high signal-to-noise ratio spectra to be obtained in relatively short integration times (1 orbit per object). ------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 2] Observations Description ------------------------ We propose to obtain spectra of five Sloan Digital Sky Survey QSOs having z^* ~ 19 using the NICMOS grism G141, with a wavelength range of approximately 1.15 Mum to 1.92 Mum. By extrapolating the flux levels of these objects from their ground-based optical spectra, we estimate them to have approximate flux levels of 60 - 90 MuJy in this wavelength range. We estimate the integration time necessary to attain a signal-to-noise ratio of approximately 10:1 per pixel for such fluxes under the following assumptions. First, we assume the 78 K detector temperature expected under the NICMOS Cryocooler System (NCS) in order to determine the background noise. We then incorporate the G141 throughput into the NICMOS Exposure Time Calculator. Using pre-NCS grism data scaled to the above flux levels, we find that such a signal-to-noise level can be achieved in approximately 500 seconds. This also agrees with the results of G141 spectra obtained in the Cycle 7 parallel program of McCarthy et al. (1999).\ The pixel response function of NICMOS Camera 3 requires a somewhat specialized observing strategy for grism observations. Specifically, this response function can leave a significant imprint on the spectra of relatively bright sources, such as those we propose to observe (see Freudling 1999, ST-ECF newsletter, http://stecf.org/newsletter/webnews1/nicmos/). Such imprints can be mistaken for the broad spectral features we are trying to detect, with a peak flux of about 10\ (see Freudling 1999, NICMOSLook manual, http://ecf.hq.eso.org/instruments/nicmos/nicmoslook/manual/ni cmoslook.html). Second, we will repeat the 500s integrations three times, placing the targets at different positions on the detector, in such a way that any imprinted features will appear in different parts of the spectra. This will allow us to verify features in the individual spectra, as well as serve as an independent check of the correction procedure. The total integration time of 1500s per object, along with the time required to acquire the targets in the F160W filter, will still allow each object to be observed in one orbit. Importantly, all of the objects are point sources and are not in crowded fields, so their spectra will not be distorted or blended with those of surrounding objects. Observations of these objects in the lower-resolution grism G206 are not feasible due to the significantly higher thermal background in the wavelength region covered by that grism. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- Program objects are very high-redshift QSOs, and are faint in the optical but bright in the near infrared. We require orientation changes in order to prevent our object spectra from overlapping with the spectra of nearby objects, and changes of position on the detector to avoid detector anomalies. ------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSPJ083643 GALAXY, QSO RA=08H 36M 43.85S +/- 0.01S, J2000.0 z = 5.82 F-CONT(16000)=1+/-0.5e-17 .85+005453.3 DEC=+00D 54' 53.3" +/- 0.2" Coordinate Source: Other_Source: Sloan Digital Sky Survey 2 SDSSPJ103027 GALAXY, QSO RA=10H 30M 27.10S +/- 0.01S, J2000.0 z = 6.28 F-CONT(16000)=1+/-0.5e-17 .10+052455.0 DEC=+05D 24' 55.0" +/- 0.2" Coordinate Source: Other_Source: Sloan Digital Sky Survey 3 SDSSPJ104433 GALAXY, QSO RA=10H 44M 33.04S +/- 0.01S, J2000.0 z = 5.73 F-CONT(16000)=1+/-0.5e-17 .04-012502.2 DEC=-01D 25' 02.2" +/- 0.2" Coordinate Source: Other_Source: Sloan Digital Sky Survey 4 SDSSPJ120823 GALAXY, QSO RA=12H 08M 23.82S +/- 0.01S, J2000.0 z = 5.27 F-CONT(16000)=1+/-0.5e-17 .82+001027.7 DEC=+00D 10' 27.7" +/- 0.2" Coordinate Source: Other_Source: Sloan Digital Sky Survey 5 SDSSPJ130608 GALAXY, QSO RA=13H 06M 08.26S +/- 0.01S, J2000.0 z = 5.99 F-CONT(16000)=1+/-0.5e-17 .26+035626.3 DEC=+03D 56' 26.3" +/- 0.2" Coordinate Source: Other_Source: Sloan Digital Sky Survey 9413( 4) - 03/04/03 09:32 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type NIC-SPIRAL-DITH Pattern_Purpose MOSAIC Number_Of_Points 4 Point_Spacing 26.214 Coordinate_Frame POS-TARG Pattern_Orient 0.112 Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 5] Visit: 01 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 SDSSPJ08364 NIC3 MULTIAC NIC3-FI F160W SAMP-SEQ=STEP8 ,NSAMP=12 1 DEF PATTERN 1 1-2 3.85+005453 CUM X .3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSPJ08364 NIC3 MULTIAC NIC3-FI G141 SAMP-SEQ=STEP64 ,NSAMP=17 1 DEF 3.85+005453 CUM X .3 ------------------------------------------------------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 6] 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 SDSSPJ10302 NIC3 MULTIAC NIC3-FI F160W SAMP-SEQ=STEP8 ,NSAMP=12 1 DEF PATTERN 1 1-2 7.10+052455 CUM X .0 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSPJ10302 NIC3 MULTIAC NIC3-FI G141 SAMP-SEQ=STEP64 ,NSAMP=17 1 DEF 7.10+052455 CUM X .0 ------------------------------------------------------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 7] Visit: 03 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 SDSSPJ10443 NIC3 MULTIAC NIC3-FI F160W SAMP-SEQ=STEP8 ,NSAMP=12 1 DEF PATTERN 1 1-2 3.04-012502 CUM X .2 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSPJ10443 NIC3 MULTIAC NIC3-FI G141 SAMP-SEQ=STEP64 ,NSAMP=17 1 DEF 3.04-012502 CUM X .2 ------------------------------------------------------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 8] Visit: 04 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 SDSSPJ12082 NIC3 MULTIAC NIC3-FI F160W SAMP-SEQ=STEP8 ,NSAMP=12 1 DEF PATTERN 1 1-2 3.82+001027 CUM X .7 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSPJ12082 NIC3 MULTIAC NIC3-FI G141 SAMP-SEQ=STEP64 ,NSAMP=17 1 DEF 3.82+001027 CUM X .7 ------------------------------------------------------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 9] Visit: 05 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 SDSSPJ13060 NIC3 MULTIAC NIC3-FI F160W SAMP-SEQ=STEP8 ,NSAMP=12 1 DEF PATTERN 1 1-2 8.26+035626 CUM X .3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSPJ13060 NIC3 MULTIAC NIC3-FI G141 SAMP-SEQ=STEP64 ,NSAMP=17 1 DEF 8.26+035626 CUM X .3 ------------------------------------------------------------------------------------------------------------------------------------ 9413( 4) - 03/04/03 09:32 - [ 10] Summary Form for Proposal 9413 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures NIC3-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations NIC3 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SAMP-SEQ=STEP8 NSAMP=12 NSAMP=17 SAMP-SEQ=STEP64 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W G141 ------------------------------------------------------------------------------------------------------------------------------------ Target Names SDSSPJ083643.85+005453.3 SDSSPJ103027.10+052455.0 SDSSPJ104433.04-012502.2 SDSSPJ120823.82+001027.7 SDSSPJ130608.26+035626.3 ------------------------------------------------------------------------------------------------------------------------------------