13380( 3) - 19-Sep-2013 15:57:08 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13380 Version: 3 Check-in Time: 19-Sep-2013 15:57:08 STScI Edit Number: 0 Title Probing Black Hole Disk Atmospheres with EPIC and RGS Observations of 4U 1957+11 ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Michael Nowak Massachusetts Institute of Technology Y CoI: Dr. Joey Neilsen Massachusetts Institute of Technology N CoI: Dr. Norbert S. Schulz Massachusetts Institute of Technology N CoI: Dr. Joern Wilms Universitat Erlangen-Nurnberg N ------------------------------------------------------------------------------------ Abstract We propose contemporaneous XMM-Newton and HST-COS observations of the black hole candidate 4U1957+11. We plan to search both the X-ray and UV spectra for evidence of a blue-shifted, magnetized wind, similar to that observed in high-resolution X-ray spectra of GRO J1655-40. ------------------------------------------------------------------------------------ Observations Description ------------------------ The observation is to be a single visit, comprised of 3 HST-orbits, employing HST-COS with the G140L grating, centered on 1280 A, to observe the UV spectrum of the Low Mass X-ray binary 4U 1957+11 (also known as V1408 Aql). All four focal plane positions are to be employed. The HST-COS observation is to be coordinated with a contemporaneous XMM-RGS observation of the X-ray spectrum. A strictly simultaneous observation with XMM-RGS is not required; the HST-COS observation can be scheduled to start within +/- 24 hours of the start of the XMM-Newton observation. Target acquisition for HST-COS is to be obtained using near UV imaging. The current best estimated position for the source has been taken from Russell et al. (2011; ApJ, 739, L19), who used DSS images (USNO-B1, GSC 2.3, and 2MASS) to arrive at the source position. This position is within 0.2" of the mean position determined from two previous sets of Chandra-HETG observations (each with 90% confidence positional uncertainties of 0.6"). The source positional uncertainty thus falls within the range of 0.4"-0.7", and we therefore use a 2X2 near UV search mode followed by near UV imaging mode. Flux estimates are derived from the median value of Swift u-band measurements, converted to Johnson U-band, assuming a flat spectrum in F_\lambda. Variability about this median is expected to be +/-40%. These flux limits are too high for FUV imaging acquisition, but even under the most liberal assumptions are a factor of several below the near UV imaging flux limits. Real Time Justification ----------------------- Calibration Justification ------------------------- 13380( 3) - 19-Sep-2013 15:57:08 - [ 2] Additional Comments ------------------- Scheduling should be coordinated with the XMM-Newton GOF. ------------------------------------------------------------------------------------ 13380( 3) - 19-Sep-2013 15:57:08 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 4U1957+11 STAR, ACCRETION DISK, RA=19H59M24.0000S +/- 0.3", J2000 V = 18.8 +/- 0.4 U-magnitude: 18+/-0.4 LMXB DEC=+11D42'29.80" +/- 0.3" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13380( 3) - 19-Sep-2013 15:57:08 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: HST-COS observation of LMXB 4U 1957+11, occuring within +/-1day of XMM-RGS observation. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 4U1957+11 COS/NUV ACQ/SEA PSA MIRRORA SCAN-SIZE=2, STEP-SIZE=1.767, 1 227 S (227 RCH CENTER=FLUX-WT S) Comments: Initial search for source postion. ------------------------------------------------------------------------------------------------------------------------------------ 2 4U1957+11 COS/NUV ACQ/IMA PSA MIRRORA 1 53 S (53 GE S) Comments: Refined search for source postion. ------------------------------------------------------------------------------------------------------------------------------------ 3 4U1957+11 COS/FUV TIME-TA PSA G140L 1280 FP-POS=1, BUFFER-TIME=13000, 1 1372 S G FLASH=YES, SEGMENT=BOTH (1372 S) Comments: Science integrations. ------------------------------------------------------------------------------------------------------------------------------------ 4 4U1957+11 COS/FUV TIME-TA PSA G140L 1280 FP-POS=2, BUFFER-TIME=13000, 1 2953 S G SEGMENT=BOTH, FLASH=YES (2953 S) Comments: Science Integrations. ------------------------------------------------------------------------------------------------------------------------------------ 5 4U1957+11 COS/FUV TIME-TA PSA G140L 1280 FP-POS=3, BUFFER-TIME=13000, 1 1424 S G FLASH=YES, SEGMENT=BOTH (1424 S) Comments: Science Integrations. ------------------------------------------------------------------------------------------------------------------------------------ 6 4U1957+11 COS/FUV TIME-TA PSA G140L 1280 FP-POS=4, BUFFER-TIME=13000, 1 1424 S G FLASH=YES, SEGMENT=BOTH (1424 S) Comments: Science Integrations. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 4U1957+11 1 COS/NUV ACQ/SEA PSA MIRRORA none none none none 1 N/A RCH 4U1957+11 2 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE 4U1957+11 3 COS/FUV TIME-TA PSA G140L 1280 none none none none 1 N/A G 4U1957+11 4 COS/FUV TIME-TA PSA G140L 1280 none none none none 2 N/A G 4U1957+11 5 COS/FUV TIME-TA PSA G140L 1280 none none none none 3 N/A G 4U1957+11 6 COS/FUV TIME-TA PSA G140L 1280 none none none none 3 N/A G 13380( 3) - 19-Sep-2013 15:57:08 - [ 5] Summary Form for Proposal 13380 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=13000, CENTER=FLUX-WT, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, SCAN-SIZE=2, SEGMENT=BOTH, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names 4U1957+11 ------------------------------------------------------------------------------------------------------------------------------------