5936( 6) - 04/24/96 11:26 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5936 Version: 6 Check-in Date: 24-Apr-1996 11:20:52 1.Proposal Title: PROBING THE LYAlpha FOREST AT 0.5 < z < 1.6 USING FLARING QUASARS AND BL LACS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Quasars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. John Stocke University of Colorado, Boulder CoI: Dr. B. McNamara New Mexico State University N CoI: Dr. William Neely NF/OBSERVATORY N CoI: Mr. M. Harvanek University of Colorado, Boulder N CoI: Mr. Steven Penton University of Colorado, Boulder N CoI: Dr. Chris Blades STSCI N CoI: Dr. Jack Burns New Mexico State University N ------------------------------------------------------------------------------------ 6. Abstract We propose spectroscopic observations of flaring quasars and BL Lacs with the FOS + high resolution gratings to study the line density and clustering of LyAlpha lines in the hitherto inaccessible redshift range 0.52 and the local LyAlpha clouds recently discovered by HST. If continuity can be established, then detailed observations of the "local" clouds can be applied to the high-z clouds as well. Current HST observations do not address the LyAlpha forest in this z range because high-z QSOs are generally not bright enough to obtain spectra at high enough SNR to detect sufficient LyAlpha absorptions to conduct a statistical study. The virtue of our 6 targets is that while they are generally quiescent at V=16-18, they occasionally flare to V < 15 for periods of several months making high SNR HST/FOS 1Angstrom resolution spectra (G190H and G270H) possible in a few ksecs. Past observations suggest that normal scheduling of these targets will be sufficient to observe them with HST in their flaring state. Each of these proposed targets is being intensively monitored using several small aperture ground-based telescopes with CCD detectors so that a flare can be detected and HST observations scheduled when the source is bright. bfThis is a continuation proposal for cycle 5 observing time previously approved for this work to provide a longer time baseline with which to observe flares in these sources. ------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 2] Observations Description ------------------------ We will obtain high SNR spectra of bright BL Lacs and quasars when they flare to V < 15 for the purpose of detecting large numbers of LyAlpha only absorption clouds at 0.5 < z < 1.6. FOS spectra will be obtained through the 0.3 arcsec circular aperture using gratings G190H and G270H. LyAlpha only and Ly Alpha + metal absorption lines will be identified in a manner similar to that described in Schneider et al (1992). At an observed equivalent width limit of ~ 100 mAngstrom (and thus a rest equivalent width limit of ~ 75 mAngstrom since the G270H will give slightly lower observed limits) we expect a LyAlpha line density of 40-80 per unit redshift in each of our objects observed (Bahcall et al, 1992; Hunstead 1988) so that a minimum of 2-3 objects will need to be observed before good statistics on line densities can be determined. Given the flaring history of these objects, we expect to observe 2- 3 of them during the two year period requested for this project. If successful, we will re-propose in a subsequent cycle to observe more flaring targets of this type. The exposure times listed for each of these targets assumes an optical magnitude of V = 15 (excepting PKS 0735+178 for which V = 14.5 is assumed) and a normal quasar spectrum (i.e. nearly a power law with spectral index of -0.5 or a (B- V)=+0.3). Using the standard DQE data from the FOS handbook checked by scaling to the results obtained by the Key Project team (Bahcall et al, 1992; Schneider et al, 1992), we have estimated the exposure times necessary to obtain 4.5 sigma observed equivalent width limit of 100 mAngstrom at 1800Angstrom and 150 mAngstrom at 3200Angstrom; this yields rest frame equivalent width limits of ~ 75 mAngstrom across the entire spectral range observed. These exposure times are 3000 and 6000 secs for the G270H and G190H gratings through the 0.3 circular arcsec aperture respectively. These are "worst case" numbers in that if our photometric monitoring show the source to be brighter than 15th, the equivalent width limits will be lower. Exceptions to this general rule are noted below: 1. PKS 0215+015: This source will not be observed with the G190H because there is a Ly limit system at 2400Angstrom observed by the IUE. 2. PKS 0735+178: This source will also be observed with the G130H grating if it flares to V < 14.5 due to the high interest in its Ly limit system at z = 0.424. This is the BL Lac in our sample which flares to the brightest apparent magnitude and can in principle yield the highest quality LyAlpha forest information of any extragalactic source excepting 3C273 and PKS 2155-304, both of which have already been oberved with HST and both of which are at substantially lower redshifts. The G130H exposure is timed to yield ~ 150 mAngstrom rest equivalent width limits at wavelengths longer than 1300Angstrom where the strong Ly limit system occurs. By assuming V = 14.0 the G130H exposure time is 7200 secs. Real Time Justification ----------------------- bfTIME-CRITICAL vspace10pt In order for these observations to be successful, the FOS spectra should be obtained ~ 1 month after STScI is notified that we have detected a flare. This requested response time is based upon the historical flaring activity of these sources (e.g. Pollock et al, 1988). Since we will continue to monitor these sources intensely with groundbased telescopes once a flare has commenced, a slightly longer leadtime can be tolerated if the source persists in its bright state. Because weeks rather than days of response time is required for success of these observations, this is NOT a target of opportunity proposal -- normal scheduling can accommodate to the flaring timescales of these quasars and BL Lacs to ensure a successful observation. Based upon the historical flaring history of these sources, we expect to actually observe 2-3 of our 6 targets in the two year time fame of this proposal. The necessity for ground-based support in this HST proposal is obvious; our photometric monitoring is essential to the success of this proposal. Due to its essential nature we have requested an amount of funding each year (~ \\30,000) in "preparatory" funds to support this continuing effort. The ground-based monitoring also supports the approved cycle 1 HST target of opportunity observations proposed by Blades et al (P2638; "The near- UV spectrum of 0215+015"). This proposal is not overlapping with P2638 because those observations involve GHRS spectra of two very strong Ly$Alpha absoprtion systems discovered by Blades et al (1985) in the IUE LWP spectrum of 0215+015 the last time it flared. Ground-based 1Angstrom resolution spectra will be obtained when the source is flaring to supplement the HST/FOS observations. These spectra are required to identify the metal line systems detected by LyAlpha in the UV. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PKS0215+015 GALAXY,BL LAC RA = 2H 17M 48.945S +/- 0.1S, 2000.0 Z=1.75 V = 15.0 DEC = +1D 44' 49.58" +/- 0.33", B-V = 0.3 PLATE-ID=04YG 2 0735+178 GALAXY,BL LAC RA = 7H 38M 07.37S +/- 0.1S, DEC 2000.0 Z=0.42 V = 14.5 = +17D 42' 18.7" +/- 0.33", B-V = 0.3 PLATE-ID=01LS 3 0846+513 GALAXY,BL LAC RA=8H 49M 58.03S +/- 0.1S, 2000.0 Z=1.86 V = 15.0 DEC=+51D 8' 29.0" +/- 0.5", B-V = 0.3 PLATE-ID=021E Comments: OBSERVE ALSO WITH FOS/BL 4 B21308+326 GALAXY,BL LAC RA=13H 10M 28.683S +/- 0.1S, 2000.0 Z=2.09 V = 15.0 DEC=+32D 20' 43.35" +/- 0.33", B-V = 0.3 PLATE-ID=01PR 5 3C446 GALAXY,BL LAC RA=22H 25M 47.031S +/- 0.1S, 2000.0 Z=1.40 V = 15.0 DEC=-4D 57' 1.4" +/- 0.5", PLATE B-V = 0.3 -ID=02O6 6 3C279 GALAXY,BL LAC RA=12H 56M 11.15S +/- 0.1S, DEC= 2000.0 Z=0.538 V = 15.0 -05D 47' 21.7" +/- 0.5", PLATE- B-V = 0.3 ID=024R 5936( 6) - 04/24/96 11:26 - [ 5] Visit: 01 Visit Requirements: ON HOLD On Hold Comments: Waiting for flare 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 0735+178 FOS/RD ACQ/BIN 4.3 MIRROR 1 1.77S ONBOARD ACQuisition FOR 2 ARY ------------------------------------------------------------------------------------------------------------------------------------ 2 0735+178 FOS/RD ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 0.2S ONBOARD ACQuisition FOR 3-5 K X=0.172,SCAN- STEP- Y=0.172,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 3 0735+178 FOS/RD ACCUM 0.3 G190H 1900 1 1598S ------------------------------------------------------------------------------------------------------------------------------------ 4 0735+178 FOS/RD ACCUM 0.3 G270H 2230- 1 1003S 3200 ------------------------------------------------------------------------------------------------------------------------------------ 5 0735+178 FOS/BL ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 0.50S ONBOARD ACQuisition FOR 6 K X=0.172,SCAN- STEP- Y=0.172,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 6 0735+178 FOS/BL ACCUM 0.3 G130H 1150- 1 3490S END ORBIT 1600 ------------------------------------------------------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 6] Visit: 02 Visit Requirements: ON HOLD On Hold Comments: Waiting for flare 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 ------------------------------------------------------------------------------------------------------------------------------------ 7 3C446 FOS/RD ACQ/BIN 4.3 MIRROR 1 2.8S ONBOARD ACQuisition FOR 8 ARY ------------------------------------------------------------------------------------------------------------------------------------ 8 3C446 FOS/RD ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 0.2S ONBOARD ACQuisition FOR 9-10 K X=0.172,SCAN- STEP- Y=0.172,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 9 3C446 FOS/RD ACCUM 0.3 G190H 1900 1 2896S ------------------------------------------------------------------------------------------------------------------------------------ 10 3C446 FOS/RD ACCUM 0.3 G270H 2230- 1 2270S 3200 ------------------------------------------------------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 7] Visit: 03 Visit Requirements: ON HOLD On Hold Comments: Waiting for flare 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 ------------------------------------------------------------------------------------------------------------------------------------ 11 PKS0215+015 FOS/RD ACQ/BIN 4.3 MIRROR 1 2.8S ONBOARD ACQuisition FOR 12 ARY ------------------------------------------------------------------------------------------------------------------------------------ 12 PKS0215+015 FOS/RD ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 0.2S ONBOARD ACQuisition FOR 13 K X=0.172,SCAN- STEP- Y=0.172,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 13 PKS0215+015 FOS/RD ACCUM 0.3 G270H 2230- 1 5275S END ORBIT 3200 ------------------------------------------------------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 8] Visit: 04 Visit Requirements: ON HOLD On Hold Comments: Waiting for flare 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 ------------------------------------------------------------------------------------------------------------------------------------ 14 0846+513 FOS/RD ACQ/BIN 4.3 MIRROR 1 2.8S ONBOARD ACQuisition FOR 15 ARY ------------------------------------------------------------------------------------------------------------------------------------ 15 0846+513 FOS/RD ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 0.2S ONBOARD ACQuisition FOR 16-17 K X=0.172,SCAN- STEP- Y=0.172,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 16 0846+513 FOS/RD ACCUM 0.3 G190H 1900 1 3276S ------------------------------------------------------------------------------------------------------------------------------------ 17 0846+513 FOS/RD ACCUM 0.3 G270H 2230- 1 2460S END ORBIT 3200 ------------------------------------------------------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 9] Visit: 05 Visit Requirements: ON HOLD On Hold Comments: Waiting for flare 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 ------------------------------------------------------------------------------------------------------------------------------------ 18 B21308+326 FOS/RD ACQ/BIN 4.3 MIRROR 1 2.8S ONBOARD ACQuisition FOR 19 ARY ------------------------------------------------------------------------------------------------------------------------------------ 19 B21308+326 FOS/RD ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 0.2S ONBOARD ACQuisition FOR 20-21 K X=0.172,SCAN- STEP- Y=0.172,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 20 B21308+326 FOS/RD ACCUM 0.3 G190H 1900 1 3700S ------------------------------------------------------------------------------------------------------------------------------------ 21 B21308+326 FOS/RD ACCUM 0.3 G270H 2230- 1 2284S END ORBIT 3200 ------------------------------------------------------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 10] Visit: 06 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 ------------------------------------------------------------------------------------------------------------------------------------ 22 3C279 FOS/BL ACQ/BIN 4.3 MIRROR 1 20.0S ONBOARD ACQuisition FOR 23 ARY ------------------------------------------------------------------------------------------------------------------------------------ 23 3C279 FOS/BL ACQ/PEA 0.3 MIRROR SCAN-STEP- 1 0.8S ONBOARD ACQuisition FOR 24 K X=0.172,SCAN- STEP- Y=0.172,SEARCH- SIZE-X=5,SEARCH Comments: -SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 24 3C279 FOS/BL ACCUM 0.3 G130H 1150- 1 3150S 1600 ------------------------------------------------------------------------------------------------------------------------------------ 25 3C279 FOS/BL ACCUM 0.3 G190H 1900 1 2350S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 5936( 6) - 04/24/96 11:26 - [ 11] Summary Form for Proposal 5936 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-X=0.172 SCAN-STEP-Y=0.172 SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Quasars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ON HOLD ONBOARD ACQuisition FOR 2 ONBOARD ACQuisition FOR 3-5 ONBOARD ACQuisition FOR 6 END ORBIT ONBOARD ACQuisition FOR 8 ONBOARD ACQuisition FOR 9-10 ONBOARD ACQuisition FOR 12 ONBOARD ACQuisition FOR 13 ONBOARD ACQuisition FOR 15 ONBOARD ACQuisition FOR 16-17 ONBOARD ACQuisition FOR 19 ONBOARD ACQuisition FOR 20-21 ONBOARD ACQuisition FOR 23 ONBOARD ACQuisition FOR 24 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G190H G270H G130H ------------------------------------------------------------------------------------------------------------------------------------ Target Names 0735+178 3C446 PKS0215+015 0846+513 B21308+326 3C279 ------------------------------------------------------------------------------------------------------------------------------------