5975( 5) - 11/20/95 15:10 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5975 Version: 5 Check-in Date: ********** 1.Proposal Title: HIGH SPATIAL RESOLUTION STUDIES OF Z>4 QUASARS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Quasars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Richard McMahon Institute of Astronomy CoI: Esther Hu Institute for Astronomy, Hawaii N CoI: Isobel Hook University of California, Berkeley N ------------------------------------------------------------------------------------ 6. Abstract def\zsol z_\odot def\zsun z_\odot defL(sun) L_\odot defL(sun) L_\odot defM(sun) M_\odot defM(sun) M_\odot We propose to carry out high spatial resolution imaging of two carefully chosen quasars with redshifts greater than four. At these redshifts the angular scales are similar to those at z=0.3 (~10kpc per arcsec for H_0=50, q_0=0.5) and the host galaxies should be both resolvable and detectable in the I(F814W) band (rest frame ~1500ang). We shall be able to study the protogalactic material surrounding these quasars at a time when the Universe was less than a billion years old. This timescale is equivalent to the dynamical timescale for a typical 100kpc galactic halo (eg Rees 1988) and the observed surface brightness distribution, or limits thereon, will be an important constraint on both quasar formation and galaxy formation scenarios. Our targets are the recently discovered, z=4.30, radio loud quasar, GB1508+5714 and the z=4.69, radio quiet quasar BR1202-0725. The former quasar is the highest redshift radio source known and the host is likely to be the progenitor of a nearby giant Elliptical galaxy. The other quasar is radio quiet and moreover it has been detected in the 300--1200Mu m wavelength range (ie ~100--200Mu m in the rest frame) with JCMT and the IRAM 30m. The inferred FIR luminosity (sim10^14L(sun)) and dust mass estimates are similar to that obtained for the z=2.3 IRAS galaxy 10214+4724. The host of this quasar is highly likely to be a spiral galaxy or some sort of interacting system. ------------------------------------------------------------------------------------ 5975( 5) - 11/20/95 15:10 - [ 2] Observations Description ------------------------ We propose to carry out deep broad band continuum observations of two z>4 quasars. The F814W filter samples the continuum longward of the Lyman-Alpha forest in these objects. \medskip Feasibility \medskip In this program we need to consider saturation effects due to the quasar nucleus and surface brightness limits. The quasar BR1202-0725 has an observed continuum flux at 1500ang in the quasar rest frame of 1.8* 10^-27 \ergpcmpHz (ie 18mJy or AB=18.2), whereas GB1505+5714 is 1mag fainter. The expected total count rate through the WFPC2 with I filter (F814W) is: \medskip 2.5* 10^11 * 0.020 * 10^- 0.4(18.2) = 283 electrons/sec \medskip Therefore, based on the figures in Table 5.1 of the WFPC handbook, if the quasar is centred on a pixel 63\ the central pixel. This drops to 20\ centred on the corner of a pixel. The ADCs saturate at 30,000electrons for gain 7 and blooming occurs at >100,000 electrons. Although saturation can be avoided by using exposures of less than 100secs, the read out noise would then dominate our observations. We propose to use exposures of 1000secs which will be sky noise limited ( cf Windhorst, Mathis & Keel, 1992) at the expense of saturating in the quasar core. \medskip Beyond a radius of 0.2arc secs the quasar contributes less than 1\ be <23.2 and 24.2 for the two quasars respectively. This is comparable with sky brightness at 8000Angstrom. \medskip A source with AB_8000=24.3 will produce a count rate of 1 ct/sec. The skybrightness at 8000Angstrom\ is 22.7 ie 4.4 ct/sec/arcsec. In 1000 seconds the targets will produce 10 counts per pixel and the sky 44 counts/pixel (ie comparable with read noise per pixel). Therefore one gets a 1 sigma detection of a point source in 1000secs. Therefore in 16 such exposures one would obtain a 4 sigma detection for a point source. This corresponds to the bf Normal galaxy formation scenario described in the scientific case. A positive detection at a level greater than this would have great significance. \medskip Total time requested We wish to obtain a total of 16,000 seconds on each quasar. This would be attained in 6 orbits for B1202-0725 and 5 orbits for GB1508+5714(near CVZ). The exposures will be split up into ~1000 second segments to facilitate Cosmic Ray removal. The quasars will be located in different places on the CCD for each orbit so that flat fielding will be improved. Real Time Justification ----------------------- none To complement our HST program we have already obtained deep narrow band Lyman-Alpha observations and broad band B, R and K observations with the University of Hawaii 88inch telescope. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5975( 5) - 11/20/95 15:10 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5975( 5) - 11/20/95 15:10 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 BR1202-0725 GALAXY, QSO RA=12H 02M 49.19S +/- 0.1S, DEC= 1950 V=19 -07D 25'50.4" +/- 1" 2 GB1508+5714 GALAXY, QUASAR RA=15H 08M 45.20S +/- 0.1S, 1950 V=19 DEC=+57D 14' 02.6" +/- 1" 5975( 5) - 11/20/95 15:10 - [ 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 BR1202-0725 WFPC2 IMAGE WF3 F814W 1 2000S POSition TARGet 0,0 ------------------------------------------------------------------------------------------------------------------------------------ 2 BR1202-0725 WFPC2 IMAGE WF3 F814W 1 2400S POSition TARGet 0.5,0.0 ------------------------------------------------------------------------------------------------------------------------------------ 3 BR1202-0725 WFPC2 IMAGE WF3 F814W 1 2400S POSition TARGet 0.0,-0.5 ------------------------------------------------------------------------------------------------------------------------------------ 4 BR1202-0725 WFPC2 IMAGE WF3 F814W 1 2400S POSition TARGet 0.5,-0.5 ------------------------------------------------------------------------------------------------------------------------------------ 5975( 5) - 11/20/95 15:10 - [ 6] Visit: 02 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 GB1508+5714 WFPC2 IMAGE WF3 F814W 1 2200S Comments: On_Hold_Comments: Visit_Comments: ------------------------------------------------------------------------------------------------------------------------------------ 2 GB1508+5714 WFPC2 IMAGE WF3 F814W 1 2600S POSition TARGet 0.5,-0.5 ------------------------------------------------------------------------------------------------------------------------------------ 5975( 5) - 11/20/95 15:10 - [ 7] Summary Form for Proposal 5975 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Quasars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POSition TARGet 0,0 POSition TARGet 0.5,0.0 POSition TARGet 0.0,-0.5 POSition TARGet 0.5,-0.5 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names BR1202-0725 GB1508+5714 ------------------------------------------------------------------------------------------------------------------------------------