Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5679 Report Date: 18-Jul-95:17:51 Version: ********** Check-in Date: ********** 1.Proposal Title: SOFT X-RAY TRANSIENTS: OUTBURSTS IN BLACK HOLE ACCRETION DISKS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO/CAR Target of Oppt. 4377 Sub Category X-RAY BINARIES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Keith Horne UTRECHT NL ------------------------------------------------------------------------------------ 7. Abstract We will observe soft X-ray transients (SXTs) as targets of opportunity using the FOS at UV wavelengths. This is part of an extensive multiwavelength 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 the 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 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 changing morphology of the accretion flow throughout the outburst. The observations will yield a detailed quantitative test of the thermal disk instability model for SXT outbursts. The interpretation of FOS observations of the SXT Nova Muscae 1991 demonstrated the critical importance to this test of recording the UV and optical spectrum during the decline. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 9.33 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5679 PI: Keith Horne Proposal Title: SOFT X-RAY TRANSIENTS: OUTBURSTS IN BLACK HOLE ACCRETION DISKS ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Keith Horne UTRECHT UNIVERSITY NL Fuhua Cheng UNIVERSITY OF MARYLAND USA Chris R. Shrader NASA GODDARD SPACE FLIGHT CENTER USA Carole A. Haswell COLUMBIA UNIVERSITY USA Wan Chen NASA GODDARD SPACE FLIGHT CENTER USA Mario Livio STSCI USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We plan 1 visit to the target in quiescence. Details of the timing of the visit and the exposure times are given in section 4b. We plan to observe the target SXT with the FOS in each of the following modes: Blue digicon / G160L, PRISM Red digicon / G270H, G400H, PRISM to obtain spectral coverage from 1100A to 6000A. These exposures will operate in RAPID mode, with READ-TIME=6.18s. This allows us to monitor short timescale variability, with good spectral resolution (SUB- STEP=4). The exposures are interleaved to allow coverage of variations around the binary orbit cycle. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. We plan 1 visit to the target at quiescence. The following table gives details of the observing strategy, aiming to record the spectrum and light curve of GROJ0422+32. FOS/RD TA1, TA2, PRISM, G270H, PRISM, G400H . 8 35 8 35 FOS/BL TA1, TA2, PRISM, G160L, PRISM, G160L, PRISM, G160L, PRISM . 8 82 8 82 8 82 8 The numbers in the table above give exposure times in minutes. All observations are in RAPID mode with READ-TIME=6.18s. Interleaved prism exposures aid in combining spectra of variable target, and serve to monitor binary orbit variations. At Peg Stanley's request we've broken the proposal into 2 scheduling units to make it easier to schedule. This compromises science unless the two units are scheduled close together in time. The planned observations are now reduced to one visit because HST scheduling delays have allowed GROJ0422+32 to fade considerably, essentially back to its quiescent level. Cycle 1 HST observations of the SXT A0620-00, taken 14 years after its 1975 outburst, showed very low ultraviolet flux, indicating that accretion to the black hole had essentially halted. The present observations of GROJ0422+32 will test whether accretion is similarly halted, or whether it continues to occur in the early quiescent phase following its Aug 1992 outburst. The observations should therefore be made as soon as possible, subject to the Cycle 3 TAC requirement that this TOO proposal must not unduely disrupt the normal scheduling process. Page 3 ------------------------------------------------------------------------------------ 8. Additional comments or special requests. There is a significant likelihood of a major SXT occurring during the duration of this proposal. Recurrence times of an individual sources vary greatly, but there has been over the last 4 years about one major event per year. These events are readily detectable by the Burst and Transient Source Experiment (BATSE) onboard Compton GRO. For example, several recent, much less dramatic events were discovered: a recurrent outbursts of 4U 1543-47 in April 1992 (Harmon, B.A. et al. 1992 IAU Circular no. 5504) and EXO 1846-031 (Shrader,C.R. and Wagner,R.M. in preparation). At the time of this writing (phase I), a new transient event has been discovered, and localized to an accuracy of 0.2 degrees similarities (Harmon, et al. 1992 IAU circ. 5584). Since the distance, the intrinsic brightness,and the galactic extinction are all totally unknown prior to an outburst, we will need to update our detailed observation plan prior to activation of the program. As discussed in other sections of the proposal, our complementary target of opportunity programs on IUE and Compton GRO will supply us with the necessary information. As discussed in section 4, we will then use information obtained through our IUE target of opportunity program to assess the feasibility and scientific value of HST observations. ------------------------------------------------------------------------------------ 11. Address Information Name: Keith Horne Category: PI Institution: University of Utrecht Address: Astronomical Institute Postbus 80000 Princetonplein 5 City: Utrecht State: Zip Code: 3508-TA Country: NL Telephone: 31-30-535234 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5679 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 GROJ0422+32 A,161,162,164,165 RA-OFF = +0.218S +/- 0.002S, 2000 1 V = 15.1 +/- 0.2 NOVA-PERSEI- DEC-OFF = -22.27" +/- 0.2", 2 E(B-V) = 0.4 +/- 0.07 1992 FROM 2 3 F-CONT(1500)= 1.0 +/- 0.25 E-14 Comments: OFFSET FROM 2 (MOVE E AND S) FLUXVALS ARE FROM OUTBURST DATA. WE EXPECT SOURCE TO BE FAINTER, ASSUME FNU=NU**1/3, V=20.0, E(B-V)=0.4 FOR EXP. CALCS. OBJECT NOT APPARENT ON GASP PLATES POSN FROM MARK WAGNER ASTROMETRY RA = 04H 21M 42.787S +/- 0.2", DEC = +32D 54' 27.09" +/- 0.2" ------------------------------------------------------------------------------------------------------------------------------------ 2 GROJ0422- I,603 RA = 04H 21M 42.618S +/- 2000 1 V = 16.69 +/- 0.2 OFFSET 0.2", DEC =+32D 54' 48.91" +/- 0.2", PLATE-ID=0051 Comments: OFFSET STAR POSN FROM GASP OFFSET STAR IS NORTH AND SLIGHTLY WEST OF GRO J0422. CLOSE ENOUGH THAT NO ADDNL GUIDE STAR ACQS REQD. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5679 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1.1 GROJ0422- FOS/RD ACQ/ 4.3 MIRROR SEARCH-SIZE-X=1 1 10S 1 ONBOARD ACQ FOR OFFSET PEAK SEARCH-SIZE-Y=3 1.2 SCAN-STEP- SEQUENTIAL 1.1 - Y=1.204 3.4 CYCLE 4 / 1.1 - 11 TARG OF OPP / 1.1 Comments: OBSERVE ASAP. B-V UNKNOWN. OK - 11 TO RE-ORDER EXPOSURES, BUT 2.1 GROUP 1.1-11 AND 3.1 NOT IN SAME HST ORBIT. WITHIN 2D TO PERMIT COORDINATED OBSERVATIONS, PLEASE NOTIFY CO- I, CAROLE HASWELL. ------------------------------------------------------------------------------------------------------------------------------------ 1.2 GROJ0422- FOS/RD ACQ/ 1.0 MIRROR SEARCH-SIZE-X=6 1 15S 1 ONBOARD ACQ FOR OFFSET PEAK SEARCH-SIZE-Y=2 1.3 SCAN-STEP- X=.602 SCAN-STEP- Y=.602 Comments: GASP PLATE EXTRACTIONS FOR THIS FIELD HAVE ERRORS ~1". USING PRECISE (0.2") ASTROMETRY FROM MARK WAGNER FOR COORDS & AND OFFSETS. SCAN PATTERN COVERS DISCREPANCY BETWEEN GASP & WAGNER ------------------------------------------------------------------------------------------------------------------------------------ 1.3 GROJ0422- FOS/RD ACQ/ 0.5 MIRROR SEARCH-SIZE-X=3 1 15S 1 ONBOARD ACQ FOR OFFSET PEAK SEARCH-SIZE-Y=3 2.1-3.5 SCAN-STEP-X=0.3 SCAN-STEP-Y=0.3 Comments: ACQUIRE WITH FOS/RD TO MINIMIZE TIME. ------------------------------------------------------------------------------------------------------------------------------------ 2.1 GROJ0422+32 FOS/RD RAPID 4.3 PRISM READ-TIME=6.18 1 475.86S 1 Comments: NOT IN SAME ORBIT AS 3.1 ------------------------------------------------------------------------------------------------------------------------------------ 2.2 GROJ0422+32 FOS/RD RAPID 4.3 G270H READ-TIME=6.18 1 2095.02 1 Comments: PLEASE EXTEND EXPOSURE TO FILL OUT SPACECRAFT ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 3.1 GROJ0422+32 FOS/RD RAPID 4.3 PRISM READ-TIME=6.18 1 475.86S 1 Comments: NOT IN SAME ORBIT AS 2.1 ------------------------------------------------------------------------------------------------------------------------------------ 3.2 GROJ0422+32 FOS/RD RAPID 4.3 G400H READ-TIME=6.18 1 2095.02 1 Comments: PLEASE EXTEND EXPOSURE TO FILL OUT SPACECRAFT ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 3.3 GROJ0422+32 FOS/BL RAPID 4.3 PRISM READ-TIME=6.18 1 475.86S 1 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5679 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 3.4 GROJ0422+32 FOS/BL RAPID 4.3 G160L READ-TIME=6.18 1 4616.46 1 Comments: SPLIT/EXTEND EXPOSURE TO FILL OUT SPACECRAFT ORBITS ------------------------------------------------------------------------------------------------------------------------------------ 3.5 GROJ0422+32 FOS/BL RAPID 4.3 PRISM READ-TIME=6.18 1 475.86S 1 ------------------------------------------------------------------------------------------------------------------------------------ 4.1 GROJ0422- FOS/BL ACQ/ 4.3 MIRROR SEARCH-SIZE-X=1 1 30S 1 ONBOARD ACQ FOR OFFSET PEAK SEARCH-SIZE-Y=3 4.2 SCAN-STEP- SEQUENTIAL 4.1 - Y=1.204 11 Comments: OBSERVE ASAP. B-V UNKNOWN. TO PERMIT COORDINATED OBSERVATIONS , PLEASE NOTIFY CO-I, CAROLE HASWELL. DO FOS/RD ACQ IF 4.1 - 4.3 WILL NOT SCHEDULE. ------------------------------------------------------------------------------------------------------------------------------------ 4.2 GROJ0422- FOS/BL ACQ/ 1.0 MIRROR SEARCH-SIZE-X=6 1 49S 1 ONBOARD ACQ FOR OFFSET PEAK SEARCH-SIZE-Y=2 4.3 SCAN-STEP- X=.602 SCAN-STEP- Y=.602 ------------------------------------------------------------------------------------------------------------------------------------ 4.3 GROJ0422- FOS/BL ACQ/ 0.5 MIRROR SEARCH-SIZE-X=3 1 49S 1 ONBOARD ACQ FOR 7- OFFSET PEAK SEARCH-SIZE-Y=3 11 SCAN-STEP-X=0.3 SCAN-STEP-Y=0.3 ------------------------------------------------------------------------------------------------------------------------------------ 7 GROJ0422+32 FOS/BL RAPID 4.3 PRISM READ-TIME=6.18 1 475.86S 1 ------------------------------------------------------------------------------------------------------------------------------------ 8 GROJ0422+32 FOS/BL RAPID 4.3 G160L READ-TIME=6.18 1 4616.46 1 Comments: SPLIT/EXTEND EXPOSURE TO FILL OUT SPACECRAFT ORBITS ------------------------------------------------------------------------------------------------------------------------------------ 9 GROJ0422+32 FOS/BL RAPID 4.3 PRISM READ-TIME=6.18 1 475.86S 1 ------------------------------------------------------------------------------------------------------------------------------------ 10 GROJ0422+32 FOS/BL RAPID 4.3 G160L READ-TIME=6.18 1 4616.46 1 Comments: SPLIT/EXTEND EXPOSURE TO FILL OUT SPACECRAFT ORBITS ------------------------------------------------------------------------------------------------------------------------------------ 11 GROJ0422+32 FOS/BL RAPID 4.3 PRISM READ-TIME=6.18 1 475.86S 1 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5679 [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP-Y=1.204 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP-X=.602 SCAN-STEP-Y=.602 SEARCH-SIZE-X=3 SCAN-STEP-X=0.3 SCAN-STEP-Y=0.3 READ-TIME=6.18 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/CAR ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 9.33 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category X-RAY BINARIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 1.2; SEQUENTIAL 1.1 - 3.4; CYCLE 4 / 1.1 - 11; TARG OF OPP / 1.1 - 11 ; GROUP 1.1-11 WITHIN 2D; ONBOARD ACQ FOR 1.3; ONBOARD ACQ FOR 2.1-3.5; ONBOARD ACQ FOR 4.2; SEQUENTIAL 4.1 - 11; ONBOARD ACQ FOR 4.3; ONBOARD ACQ FOR 7-11; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR PRISM G270H G400H G160L ------------------------------------------------------------------------------------------------------------------------------------ Target Names GROJ0422+32 NOVA-PERSEI-1992 GROJ0422-OFFSET ------------------------------------------------------------------------------------------------------------------------------------