12919( 2) - 10-Jul-2012 15:54:30 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12919 Version: 2 Check-in Time: 10-Jul-2012 15:54:30 STScI Edit Number: 0 Title Physics of Black Hole Transients from Simultaneous X-Ray and UV Observations ------------------------------------------------------------------------------------ Type Cycle GO 20 ------------------------------------------------------------------------------------ Investigators Contact? PI: Ms. Alexandra Veledina University of Oulu, Dept. of Astronomy Y CoI: Dr. Jari Kajava University of Oulu, Dept. of Astronomy N CoI: Dr. Juri Poutanen University of Oulu, Dept. of Astronomy N CoI: Dr. Piergiorgio Casella INAF, Osservatorio Astronomico di Roma N CoI: Dr. Vitaly Neustroev University of Oulu, Dept. of Astronomy N ------------------------------------------------------------------------------------ Abstract Fundamental questions concerning processes in the vicinity of black holes (BH) remain open. The accretion flow geometry, the role of the jet and the source of optical radiation are among most disputed. In recent years, simultaneous infrared/optical/ultraviolet--X-ray observations revealed their large potential in addressing these problems. By joining two powerful astrophysical techniques: (a) high-resolution X-ray spectroscopy and timing (which only XMM-Newton can provide) and (b) high time-resolution UV photometry (available only at HST), we will answer a number of fundamental questions of BH physics. We will constrain the accretion flow geometry, measure the inner disc radius, identify the source of seed photons for Comptonization, and locate the zone of the UV emission. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will observe two accreting black holes, SWIFT J1753.5-0127 and a new black hole transient. The HST observing time is two orbits per target. The FUV observations should be performed strictly simultaneously with the X-ray observation by XMM-Newton within the allocated 20 ks (per target). The science aim is to check their connection and to contrain the physics of the accretion and the source of radiation from the UV to X-rays. We will use HST/COS/FUV/G140L in the TIME-TAG mode to observe time variability in the FUV continuum together with X-ray variations as observed by XMM-Newton (in EPIC-PN timing mode). Spectral information will be used to estimate the absorption towards the sources as well as to measure the spectral shape and to distinguish between various emission candidates (accretion disk, synchrotron). Target 1: The scheduled observation of SWIFT J1753.5-0127 can be performed either before 12-Oct-2012 or during the periods 8-Mar-2013 to 18-Mar-2013 or 5-Apr-2013 to 8-Apr-2013 when the object is visible by both HST and XMM-Newton. The object with V magnitude of 16.5+-0.5 has been very stable during the past five years. It has a power-law spectrum of F_\lambda \propto \lambda^-1.4 and extinction E(B-V)=0.3. The estimated count rate in G140L is approximately 200 cts/s. The UV flux will be also checked a week before scheduled observation using Swift/UVOT. 12919( 2) - 10-Jul-2012 15:54:30 - [ 2] Target 2 is a new black hole X-ray transient. We will perform a non-disruptive ToO. The observations by HST and XMM-Newton are triggered on a black hole transient, when it undergoes an outburst. The outbursts follow a typical pattern of a decay with an e-folding time of 0.5-1 month. At the peak of the outburst, a transient will most likely be too bright for XMM-Newton (upper limit =1000 cts/s) and therefore the observations should be performed a few weeks after the outburst peak. Using the MAXI and Swift/UVOT data, we can predict, when the count rates drop below the upper limits and trigger the ToO two weeks in advance. The main trigger condition is the sufficiently low X-ray count rate, in order not to exceed the maximum allowed XMM-Newton count rate (1000 cts/s), together with the sufficiently low UV count rate, allowed by the HST/COS, below 15, 000 cts/s. For a typical BH transient with a sufficiently low extinction the expected HST/COS/FUV/G140L count rate is between 200 and 2000 cts/s, which is safe for the instrument and allows us to achieve our science goals. Observations are possible after the predicted date, whenever possible for both telescopes. However, the observations should take place before the object becomes undetectable again (on a timescale of a few months). Real Time Justification ----------------------- We need a minimum of 3000 sec (per target) of simultaneous exposure with the XMM-Newton. We were awarded 20 000 sec of the XMM-Newton time per target, so the observations should be scheduled any time within that period. Our scientific goal is to investigate radiation mechanisms of the black hole X-ray transients. In order to achieve it, we are looking for a connection between the UV and the X-ray light-curves by calculating their cross-correlation function. Any features it will show would provide us with the unique information about the processes operating in the vicinity of the compact object. The significance levels of these features depend on the square root of the duration of simultaneous exposure. Our calculations show that for typical X-ray and FUV count rates of 100 cts/s and 1000 cts/s in order to detect the anticipated features at 5 sigma level, the minimum duration is 3000 sec. Any duration, which is longer than this time would result in a considerable improvement of the significance. As the count rates are difficult to estimate in advance of observations, we require two full HST orbits to achieve the science goals. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12919( 2) - 10-Jul-2012 15:54:30 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SWIFTJ1753.5 STAR, LMXB RA=17H53M28.2900S +/- 0.3", J2000 V = 16.5 +/- 1 -0127 DEC=-01D27'6.20" +/- 0.3" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 12919( 2) - 10-Jul-2012 15:54:30 - [ 4] TARGET LIST Generic Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Selection Criteria | Flux data No | Name | Description | | ------------------------------------------------------------------------------------------------------------------------------------ 2 BHTRANSIENT STAR, LMXB, X-RAY OTHER: COUNT RATE IS BELOW 15000 V = 14.0 +/- 1.0 TRANSIENT CTS/SEC AND ABOVE 1000 CTS/SEC ------------------------------------------------------------------------------------------------------------------------------------ 12919( 2) - 10-Jul-2012 15:54:30 - [ 5] Visit: 01 Visit Requirements: BETWEEN 31-AUG-2012 AND 12-OCT-2012; BETWEEN 27-FEB-2013 AND 04-MAR-2013; BETWEEN 08-MAR-2013 AND 31-MAR-2013; BETWEEN 04-APR-2013 AND 08-APR-2013 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SWIFTJ1753. COS/NUV ACQ/IMA PSA MIRRORB 1 171.2 S 5-0127 GE ------------------------------------------------------------------------------------------------------------------------------------ 2 SWIFTJ1753. COS/FUV TIME-TA PSA G140L 1280 EXTENDED=NO, FP-POS=ALL, 1 700 S 5-0127 G SEGMENT=BOTH, FLASH=YES, see below BUFFER-TIME=920 Comments: We require the science time of minimum 3000 s to be within the XMM-Newton exposure time (where we have 20 ksec). ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SWIFTJ1753.5-0127 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE SWIFTJ1753.5-0127 2 COS/FUV TIME-TA PSA G140L 1280 none none none 1 1 1040.0 S G SWIFTJ1753.5-0127 2 COS/FUV TIME-TA PSA G140L 1280 none none none 2 1 1041.0 S G SWIFTJ1753.5-0127 2 COS/FUV TIME-TA PSA G140L 1280 none none none 3 2 1400.0 S G SWIFTJ1753.5-0127 2 COS/FUV TIME-TA PSA G140L 1280 none none none 4 2 1400.0 S G 12919( 2) - 10-Jul-2012 15:54:30 - [ 6] Visit: 02 Visit Requirements: ON HOLD On Hold Comments: The observation is a simultaneous (soft trigger) ToO with the XMM-Newton. Trigger condition for HST is the count rate (in the entire detector) below the upper limit of 15000 cts/s and above the lower limit of 1000 cts/s. And for XMM-Newton the criteria are the X-ray count rate below 1000 cts/s and above 100 cts/sec. Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 BHTRANSIENT COS/NUV ACQ/SEA PSA MIRRORB CENTER=FLUX-WT-FLR, 1 7.7 S RCH SCAN-SIZE=3, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ 2 BHTRANSIENT COS/NUV ACQ/IMA PSA MIRRORB 1 7.7 S GE ------------------------------------------------------------------------------------------------------------------------------------ 3 BHTRANSIENT COS/FUV TIME-TA PSA G140L 1280 BUFFER-TIME=900, EXTENDED=NO, 1 1000 S G FLASH=YES, FP-POS=ALL, see below SEGMENT=BOTH Comments: We require minimum of 3000 s of the science exposure time to be within the XMM-Newton exposure time (where we have 20 ksec). ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ BHTRANSIENT 1 COS/NUV ACQ/SEA PSA MIRRORB none none none none 1 N/A RCH BHTRANSIENT 2 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE BHTRANSIENT 3 COS/FUV TIME-TA PSA G140L 1280 none none none 1 1 1000.0 S G BHTRANSIENT 3 COS/FUV TIME-TA PSA G140L 1280 none none none 2 1 1029.0 S G BHTRANSIENT 3 COS/FUV TIME-TA PSA G140L 1280 none none none 3 2 1400.0 S G BHTRANSIENT 3 COS/FUV TIME-TA PSA G140L 1280 none none none 4 2 1400.0 S G 12919( 2) - 10-Jul-2012 15:54:30 - [ 7] Summary Form for Proposal 12919 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=900, BUFFER-TIME=920, CENTER=FLUX-WT-FLR, EXTENDED=NO, FLASH=YES, FP-POS=ALL, SCAN-SIZE=3, SEGMENT=BOTH, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 04-APR-2013 AND 08-APR-2013, BETWEEN 08-MAR-2013 AND 31-MAR-2013, BETWEEN 27-FEB-2013 AND 04-MAR-2013, BETWEEN 31-AUG-2012 AND 12-OCT-2012, ON HOLD ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names BHTRANSIENT, SWIFTJ1753.5-0127 ------------------------------------------------------------------------------------------------------------------------------------