8245( 29) - 01/07/00 09:16 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8245 Version: 29 Check-in Date: 07-Jan-2000 09:15:05 1.Proposal Title: BLACK HOLE ACCRETION OUTBURSTS IN SOFT X- RAY TRANSIENTS ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Carole Haswell The Open University CoI: Mr. Robert Hynes University of Sussex N CoI: Prof. Keith Horne University of St. Andrews N CoI: Dr. Chris Shrader NASA Goddard Space Flight Center N CoI: Dr. Wan Chen NASA Goddard Space Flight Center N CoI: Dr. Fuhua Cheng University of Villanova N CoI: Prof. Mario Livio Space Telescope Science Institute N CoI: Dr. Mark Wagner Ohio State University (Steward) N CoI: Prof. Edward Robinson The University of Texas at Austin N ------------------------------------------------------------------------------------ 5. Abstract UV observations of soft X-ray transients (SXTs) will be made using STIS. This is part of an extensive multiwavelength target of opportunity campaign to monitor newly discovered SXTs in outburst and throughout the subsequent decline. Recent work establishes that a high proportion of SXTs harbor black holes, so these observations provide an unrivalled opportunity to obtain high quality data from an accreting black hole. UV data is a keystone of our multiwavelength campaign because the disk regions of interest radiate predominantly in the UV. Emission lines will allow us to probe the kinematics of the inner disk region. We will examine the relative strengths of the reprocessed X-ray flux emitted in the UV, and the UV flux generated by viscous heating in the accretion flow. Multiwavelength observations will probe the physics of the accretion flow throughout the outburst. The observations will yield detailed quantitative tests of the models for SXT outbursts. The new STIS/MAMA capability to perform UV spectroscopy with 125 microsecond time resolution will be exploited. A proven HST/RXTE echo-mapping experiment will measure the size of the reprocessing regions in the accretion disk, and thus probe morphology changes as the decline proceeds. It is unknown what rapid UV variability we may find; recent RXTE discoveries suggest this may prove a rich source of information on the dynamics close to the event horizon. ------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 2] Observations Description ------------------------ We plan a total of 7 HST/STIS visits to the target throughout the decline from outburst. Since we do not yet know the coordinates of the target, we assume the average visibility window of 54 minutes, and use the standard ACQ/PEAK acquisition. To calculate exposure times we assume a typical SXT lightcurve with V_max = 13.0 and E(B-V)=0.3. Where practical we aim for a signal-to-noise per resolution element of 50 for CCD observations and 30 for MAMA data. To cover the entire decline and keep the request reasonable, this goal is compromised in later visits. For CCD exposures we impose the minimum requirement that the exposure should not be read- noise dominated and that at least as much time should be spent on the target as is taken up by calibrations. Extra minutes were added or subtracted as necessary to pack the orbits; these adjustments will vary with the visibility window. Our principal observational goals are: beginitemize vspace-2mm em To obtain a high quality spectrum spanning 1150 - 10300 Angstrom from each visit. This will be accomplished with a series of observations with the G140L, G230L, G430L and G750L gratings in each visit. vspace-3mm em To obtain the best possible UV spectrum early in the outburst in order to determine the reddening of the source from the 2175 Angstrom interstellar feature (see Fig. 1). vspace-3mm em To obtain high time resolution UV data simultaneous with XTE coverage. We achieve this by taking G140L and G230L exposures in TIMETAG mode. To obtain sufficient timing data, we have budgeted more time with these gratings than demanded by pure spectral signal-to-noise requirements. vspace-2mm enditemize In addition, in the first visit we exploit the UV echelle capabilities (also in TIMETAG mode) to obtain a high resolution spectrum covering the prominent resonance lines. This potentially combines 125Mu second time resolution with superb velocity resolution. In the second visit we budget time to obtain a series of short exposures with the G430L grating to monitor variability in important lines in the blue and near ultraviolet: H-beta, HeII and various Bowen fluorescence lines. All of these were seen in the spectrum of GRO J1655- 40. The table below summarises our program. This is provisional and will change depending on the actual magnitude, reddening, and visibility window. We have, of course, prepared detailed plans for observations of targets with various reddenings and peak brightnesses. beginverbatim Visit Orbits Time V E140M G140L G230L G430L G750L (days) (mag) 1 5 0 13.00 73m 50m 34m 3m 5m 2 3 10 13.27 38m 22m 15m 5m 3 2 20 13.54 33m 21m 3m 5m 4 2 50 14.36 33m 20m 4m 5m 5 3 80 15.12 54m 25m 8m 7m 6 2 110 16.00 33m 15m 8m 7m 7 3 140 16.82 54m 25m 8m 7m endverbatim While the optical spectra could, in principle, be obtained from the ground, in practice it is difficult to get exactly coordinated ground-based spectroscopy. Since the spectrum is evolving, relying exclusively on contemporaneous optical coverage introduces highly undesirable uncertainties into our bolometric spectrum. Ground-based observations are also subject to cloud and telluric absorption features. The marginal cost of using HST to obtain near-simultaneous optical data is small (as indicated by the exposure times above) compared with the cost of making a visit to the target and taking the UV data which only HST can acquire. Real Time Justification ----------------------- The recurrence times of individual sources vary greatly, and are unpredictable, hence we require Target of Opportunity observations. There is a significant likelihood of a major transient event occurring during the duration of this proposal. Over the last 9 years five suitable targets were discovered, some showing recurrent behavior. Prompt observations, within a week of discovery if possible, are highly desirable. Early observations, when \dot M ~ \dot M_Edd hold the most potential for ground-breaking discoveries, and as the source fades, data quality will decline. We will trigger the HST program only if a major SXT, reaching ~ 1 Crab and/or V ~ 14, occurs. RXTE will make observations simultaneously with HST for echo-mapping. The burden of coordinating schedules will fall upon RXTE, which is far more flexible than HST. While logistically challenging, the superb efforts at NASA/Goddard and STScI for our 1996 campaign on GRO J1655-40 showed that this fine-tuned scheduling can be achieved. RXTE provided simultaneous data covering 4 of our 5 successful HST visits ( e.g. Figs 7, 8). We have in place a multiwavelength network of Target of Opportunity programs to observe SXTs. RXTE and GRO will provide early detection, and subsequently monitor the X-ray intensity. Hence, ``real time'' planning of observations at other wavelengths is facilitated. We hold formally approved ToOs to follow the decline in support of the HST program with RXTE (X-rays, PI Chen); AAT (optical spectra, PI Harlaftis); and UKIRT (IR photometry, PI Haswell). Other ToO proposals are pending. At Lowell and McDonald observatories we have preferred access to high quality ground-based observations. Our team includes guest observers at many other facilities, and we have a large informal network of collaborators, including radio astronomers in the US, the UK, and the Netherlands. We have demonstrated (Figs. 7 and 8) that simultaneous RXTE observations can be achieved. As planned, our 1996 HST/RXTE campaign on GRO J1655-40 was adequately supported by ground-based observations (Hynes, Haswell et al. 1998a; Hynes et al. 1998c). A northern transient would benefit from even more lavish ground-based support. The HST schedule will drive our scheduling requests of the other facilities. Calibration Justification ------------------------- Additional Comments ------------------- Have removed the visits planned for the generic target BRIGHT-X-RAY-TRANSIENT. Need to resolve science/technical tradeoffs for this possibility in light of the news that the NDQ* neutral density filter modes may not be flux calibrated :( Hence will need to update generic phase II later. ------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 3] Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 X-RAY- STAR, INTERACTING RA=18H 58M 41.58S +/- 0.04S, J2000 V = 15.5 TRANSIENT BINARY, X-RAY NOVAE, X- DEC=22D 39' 29.4" +/- 0.5" RAY TRANSIENT, LMXB 8245( 29) - 01/07/00 09:16 - [ 5] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 14-Oct-1999 AND 21-Oct-1999 ON HOLD On Hold Comments: This is a target of opportunity. Additional Comments: Assume V=15.50. Visit goals are a) Obtain high quality multiwavelength spectrum, b) Obtain good coverage of 2175 feature to allow determination of reddening, c) Obtain extensive time-tag UV data, to correlate with XTE Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 X-RAY-TRANS STIS/C ACQ F28X50L MIRROR 1 2 S IENT CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1125 1 2250 S IENT UV-MAM G A Comments: Buffer-time set to exposure / 2 as per K.Sahu instructions ------------------------------------------------------------------------------------------------------------------------------------ 3 X-RAY-TRANS STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=800 1 2300 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 4 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1150 1 2300 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 5 X-RAY-TRANS STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=125 1 250 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 6 X-RAY-TRANS STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2 1 300 S IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 7 X-RAY-TRANS STIS/C ACCUM 52X0.5 G750L 7751 CR-SPLIT=2 1 200 S IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 8 CCDFLAT STIS/C ACCUM 0.3X0.0 G750L 7751 BINAXIS1=1,BINAXIS2=1 2 25 S CD 9 ------------------------------------------------------------------------------------------------------------------------------------ 9 X-RAY-TRANS STIS/C ACCUM 52X0.5 G750L 8975 CR-SPLIT=2 1 300 S EXPAND IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 10 CCDFLAT STIS/C ACCUM 0.3X0.0 G750L 8975 BINAXIS1=1,BINAXIS2=1 2 25 S CD 9 ------------------------------------------------------------------------------------------------------------------------------------ 11 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1150 1 2300 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 6] Visit: 02 Visit Priority: Visit Requirements: ON HOLD AFTER 01 BY 9 D TO 11 D On Hold Comments: This is a target of opportunity. Coordinates, fluxes, and timing information are unknown until newly outbursting SXT triggers the program. The visit program will be tailored to the properties of the object and the visibility window. Additional Comments: Assume V=15.77. Visit goals are: a) Obtain high quality multiwavelength spectrum, b) Obtain extensive time-tag UV data, to correlate with XTE, c) Obtain time-resolved G430L spectra to examine variability in H-Beta, HeII and Bowen fluorescence lines. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 X-RAY-TRANS STIS/C ACQ F28X50L MIRROR 1 2 S IENT CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1125 1 2250 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 3 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=675 1 1350 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 4 X-RAY-TRANS STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2 1 300 S IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 5 X-RAY-TRANS STIS/C ACCUM 52X0.5 G750L 7751 CR-SPLIT=2 1 200 S IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 6 CCDFLAT STIS/C ACCUM 0.3X0.0 G750L 7751 BINAXIS1=1,BINAXIS2=1 2 25 S CD 9 ------------------------------------------------------------------------------------------------------------------------------------ 7 X-RAY-TRANS STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=800 1 2300 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 7] Visit: 03 Visit Priority: Visit Requirements: ON HOLD AFTER 01 BY 19 D TO 21 D On Hold Comments: This is a target of opportunity. Coordinates, fluxes, and timing information are unknown until newly outbursting SXT triggers the program. The visit program will be tailored to the properties of the object and the visibility window. Exposures should be lengthened or shortened as necessary Additional Comments: Assume 16.04. Visit goals are: a) Obtain high quality multiwavelength spectrum, b) Obtain time-tag UV data, to correlate with XTE. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 X-RAY-TRANS STIS/C ACQ F28X50L MIRROR 1 2.5 S IENT CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 X-RAY-TRANS STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=800 1 2200 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 3 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=425 1 850 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 5 X-RAY-TRANS STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2 1 400 S IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 6 X-RAY-TRANS STIS/C ACCUM 52X0.5 G750L 7751 CR-SPLIT=2 1 300 S EXPAND IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 7 CCDFLAT STIS/C ACCUM 0.3X0.0 G750L 7751 BINAXIS1=1,BINAXIS2=1 2 25 S CD 9 ------------------------------------------------------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 8] Visit: 06 Visit Priority: Visit Requirements: ON HOLD BETWEEN 01-Feb-2000:01:30:00.0 AND 01-Feb-2000:05:00:00.0 BETWEEN 01-Feb-2000:19:45:00.0 AND 01-Feb-2000:23:00:00.0 BETWEEN 08-Feb- 2000:16:30:00.0 AND 09-Feb-2000:23:00:00.0 On Hold Comments: This is a target of opportunity. Additional Comments: Assume 16.00. Visit goals are: a) Obtain multiwavelength spectrum, b) Obtain time-tag UV data, to correlate with XTE. BETWEEN requirements represent best intersection of the following: AFTER 01 BY 105D TO 115D Best XTE coordination dates: Feb 1, 2000 and Feb 9, 2000. These dates should be checked again when better HST and XTE orbit models are available for February 2000. Best times of day for coordinated ground based observing: 19:45-23:00 UT and 01:30-5:00 UT. These times should be checked again closer February 2000. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 X-RAY-TRANS STIS/C ACQ F28X50L MIRROR 1 160 S IENT CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=750 1 1500 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 3 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=575 1 1150 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 4 X-RAY-TRANS STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2 1 450 S IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 5 X-RAY-TRANS STIS/C ACCUM 52X0.5 G750L 7751 CR-SPLIT=2 1 250 S EXPAND IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 6 CCDFLAT STIS/C ACCUM 0.3X0.0 G750L 7751 BINAXIS1=1,BINAXIS2=1 2 25 S CD 9 ------------------------------------------------------------------------------------------------------------------------------------ 7 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1400 1 2800 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8 X-RAY-TRANS STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=450 1 2800 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1400 1 2800 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 9] Visit: 07 Visit Priority: Visit Requirements: ON HOLD BETWEEN 04-Mar-2000 AND 07-Mar-2000 VISIBILITY INTERVAL 52 M On Hold Comments: This is a target of opportunity. Additional Comments: Assume 16.00. Visit goals are: a) Obtain multiwavelength spectrum, b) Obtain time-tag UV data, to correlate with XTE. BETWEEN requirements represent best intersection of the following: AFTER 01 BY 105D TO 115D Best XTE coordination dates: Feb 1, 2000 and Feb 9, 2000. These dates should be checked again when better HST and XTE orbit models are available for February 2000. Best times of day for coordinated ground based observing: 19:45-23:00 UT and 01:30-5:00 UT. These times should be checked again closer February 2000. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 X-RAY-TRANS STIS/C ACQ F28X50L MIRROR 1 160 S IENT CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=750 1 1500 S IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 3 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=575 1 16 M IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 4 X-RAY-TRANS STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2 1 450 S MAX DUR IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 5 X-RAY-TRANS STIS/C ACCUM 52X0.5 G750L 7751 CR-SPLIT=2 1 250 S MAX DUR IENT CD ------------------------------------------------------------------------------------------------------------------------------------ 6 CCDFLAT STIS/C ACCUM 0.3X0.0 G750L 7751 BINAXIS1=1,BINAXIS2=1 2 25 S CD 9 ------------------------------------------------------------------------------------------------------------------------------------ 7 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1400 1 46 M IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8 X-RAY-TRANS STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=450 1 46 M IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9 X-RAY-TRANS STIS/F TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=1400 1 46 M IENT UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8245( 29) - 01/07/00 09:16 - [ 10] Summary Form for Proposal 8245 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.5 0.3X0.09 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ TIME-TAG ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1125 BUFFER-TIME=800 BUFFER-TIME=1150 BUFFER-TIME=125 CR-SPLIT=2 BINAXIS2=1 BINAXIS1=1 BUFFER-TIME=675 BUFFER-TIME=425 BUFFER-TIME=750 BUFFER-TIME=575 BUFFER-TIME=1400 BUFFER-TIME=450 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 14-Oct-1999 AND 21-Oct-1999 ON HOLD EXPAND ON HOLD AFTER 01 BY 9 D TO 11 D ON HOLD AFTER 01 BY 19 D TO 21 D ON HOLD BETWEEN 01-Feb-2000 01 30 00.0 AND 01-Feb-2000 05 00 00.0 BETWEEN 01-Feb-2000 19 45 00.0 AND 01-Feb-2000 23 00 00.0 BETWEEN 08-Feb-2000 16 30 00.0 AND 09-Feb-2000 23 00 00.0 ON HOLD BETWEEN 04-Mar-2000 AND 07-Mar-2000 VISIBILITY INTERVAL 52 M MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L G230L G430L G750L ------------------------------------------------------------------------------------------------------------------------------------ Target Names X-RAY-TRANSIENT CCDFLAT ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 2376 4300 7751 8975 ------------------------------------------------------------------------------------------------------------------------------------