16079( 4) - 01-May-2020 16:49:00 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16079 Version: 4 Check-in Time: 01-May-2020 16:49:00 STScI Edit Number: 2 Title Does the binary system LB-1 host a Black Hole? ------------------------------------------------------------------------------------ Type Cycle GO 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Daniel J. Lennon Instituto de Astrofisica de Canarias Y CoI: Dr. Jesus Maiz Apellaniz Centro de Astrobiologia (CSIC/INTA) Inst. N Nac. de Tec. Aero. CoI: Dr. Ralph C. Bohlin Space Telescope Science Institute N CoI: Dr. Susana E. Deustua Space Telescope Science Institute N CoI: Prof. Artemio Herrero Instituto de Astrofisica de Canarias N CoI: Dr. Stephen J. Smartt The Queen's University of Belfast N CoI: Dr. Philip Dufton The Queen's University of Belfast N CoI: Dr. Jonay I. Gonzalez-Hernandez Instituto de Astrofisica de Canarias N CoI: Dr. Carlos Allende-Prieto Instituto de Astrofisica de Canarias N CoI: Dr. Norberto Castro Leibniz-Institut fur Astrophysik Potsdam N (AIP) CoI: Mr. Abel de Burgos Sierra Nordic Optical N CoI: Dr. Jorges Casares Instituto de Astrofisica de Canarias N CoI: Dr. Teo Munoz Darias Instituto de Astrofisica de Canarias N CoI: Dr. Sergio Simon-Diaz Instituto de Astrofisica de Canarias N ------------------------------------------------------------------------------------ Abstract It was recently proposed that the Galactic binary system LB-1 hosts an ~8+70 solar mass B-star+black hole (BH) wide binary that is X-ray quiet, strongly challenging the current paradigm for the formation of stellar mass black holes in metal rich environments. This claim was quickly disputed in two ways: The Balmer emission lines originally thought to arise from an accretion disk around the BH have been re-interpreted as a stationary circumbinary disk, hence it is only possible to estimate a minimum mass for the dark companion from the inferred mass of the B-type star. Secondly, detailed non-LTE analyses of the optical spectrum and spectral energy distribution of the B-type star now imply two scenarios for a significantly lower mass of the B-type 'primary': It is found to be either a main sequence B-type star of 3.2+/-2 solar masses or a stripped helium star of 1.1+/-0.5 solar masses, consistent with a 'secondary' mass between approximately 2 and 5 solar masses. The dark secondary could therefore still be a stellar mass BH, making it only the second X-ray quiet star+BH system known, or possibly even a massive neutron star. We propose obtaining an exquisite UV/optical/near-IR flux calibrated spectrum of the system that will provide the pivotal means of discriminating between these two scenarios by tightly constraining the mass and helium abundance of the primary. ------------------------------------------------------------------------------------ Observations Description ------------------------ We follow the standard STIS and WFC3/IR flux calibration configurations, aiming for a s/n of at least 100--200, and a combined spectrum covering the FUV--near-IR with a spectral resolution of 500-1000 in the UV-optical, and 16079( 4) - 01-May-2020 16:49:00 - [ 2] 100-200 in the near-IR. For the predicted UV flux we adopt the parameters and extinction law from Simon-Diaz et al (their Appendix C). The source is non-variable and the extinction law is well enough determined to permit a reliable estimate of BOP concerns. We require a total of 3 orbits/visits as follows: VISIT O1: For a s/n of approximately 100 with STIS/MAMA using the 52x2 aperture and NUV G140L and FUV G230L configurations we require exposure times of at least 1000 and 800 seconds respectively. Exposure times are auto-adjusted to fill the orbit and improve s/n. We switch off the MAMA monthly offsets as this improves flux calibration to better than 3%, an objective of the proposal. Wavecals are explicitly added. VISIT 02: For the STIS/CCD G430L and G750L detector/grating combinations exposure times are short, 20 seconds for s/n around 100 and we therefore repeat each x4 times (CRSPLIT=4) to match STIS calibration observations. We will use the 52x2 aperture, the E1 position for the G430L to mimimize CTE losses and the center position for G750L as per the standard calibration configurations. To complete this orbit we will add higher resolution G430M/3680 and G430M/3936 150/50 second exposures with the 52x0.1E1 aperture. These data will permit a very high fidelity view of the Balmer jump and the higher series members of the Balmer lines from Hepsilon onwards. In addition we note that the use of the 2 arcsec wide aperture in the low resolution observations will in effect provide imaging spectroscopy of the disk emission lines. Wavecals are explicitly added. VISIT 03: With WFC3/IR we require use of the G102 and G141 grisms. We use an 8-point line dither pattern in Y of 10 pixels to improve the total s/n and reduce persistence effects. Using the 512 subarray, we can obtain 2 patterns per grism in a single orbit, for a total exposure time per grism of 102 seconds. A short exposure is added at the end of the sequence to define position of the source for the grism observations. We add short imaging exposures to check the Paschen Beta for extended emission. We use the 256 subarray to avoid saturation of the target. ------------------------------------------------------------------------------------ 16079( 4) - 01-May-2020 16:49:00 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LS-V-+22-25 EXT-STAR, B6-B9.5 III-I RA=06H11M49.0762S, J2000 V = 11.51 +/- 0.1 DEC=+22D49'32.66" Reference Frame: ICRS Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 -4.846175616301932E-6 -0.0018890000092142145 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 16079( 4) - 01-May-2020 16:49:00 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 8 Point_Spacing 1.3 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16079( 4) - 01-May-2020 16:49:00 - [ 5] Visit: 01 (LB1 MAMA SPEC) Visit Requirements: 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LS-V-+22-25 STIS/CCD ACQ F28X50LP MIRROR 1 0.2 S (0.2 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NONE STIS MSMOFF SETOFFSET=ZERO, GRATING1=ALL 1 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LS-V-+22-25 STIS/FUV ACCUM 52X2 G140L 1425 WAVECAL=NO 1 1000 S -MAMA see below (1040 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 52X0.05 G140L 1425 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 LS-V-+22-25 STIS/NUV ACCUM 52X2 G230L 2376 WAVECAL=NO 1 800 S -MAMA see below (840 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WAVE STIS/NUV ACCUM 31X0.05ND G230L 2376 1 DEF (0 S) -MAMA C ------------------------------------------------------------------------------------------------------------------------------------ 7 NONE STIS MSMOFF SETOFFSET=RESTORE, 1 DEF (0 S) GRATING1=ALL ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ LS-V-+22-25 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A NONE 2 STIS MSMOFF none none none none 1 N/A LS-V-+22-25 3 STIS/FUV ACCUM 52X2 G140L 1425 none none none none 1 1040.0 S -MAMA WAVE 4 STIS/FUV ACCUM 52X0.05 G140L 1425 none none none none 1 N/A -MAMA LS-V-+22-25 5 STIS/NUV ACCUM 52X2 G230L 2376 none none none none 1 840.0 S -MAMA WAVE 6 STIS/NUV ACCUM 31X0.05N G230L 2376 none none none none 1 N/A -MAMA DC NONE 7 STIS MSMOFF none none none none 1 N/A 16079( 4) - 01-May-2020 16:49:00 - [ 6] Visit: 02 (LB1 CCD SPEC) Visit Requirements: 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LS-V-+22-25 STIS/CCD ACQ F28X50LP MIRROR 1 0.5 S (0.5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 LS-V-+22-25 STIS/CCD ACQ/PEA 52X0.1E1 MIRROR 1 0.2 S (0.2 K S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LS-V-+22-25 STIS/CCD ACCUM 52X0.1E1 G430M 3680 1 150 S see below (242 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/CCD ACCUM 52X0.2 G430M 3680 CR-SPLIT=NO 1 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 LS-V-+22-25 STIS/CCD ACCUM 52X0.1E1 G430M 3936 1 50 S see below (142 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WAVE STIS/CCD ACCUM 52X0.2 G430M 3936 1 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 LS-V-+22-25 STIS/CCD ACCUM 52X2E1 G430L 4300 CR-SPLIT=4, WAVECAL=NO 1 80 S see below (264 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/CCD ACCUM 52X0.2 G430L 4300 CR-SPLIT=NO 1 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 9 LS-V-+22-25 STIS/CCD ACCUM 52X2 G750L 7751 CR-SPLIT=4 1 20 S see below (204 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 WAVE STIS/CCD ACCUM 52X0.2 G750L 7751 CR-SPLIT=NO 1 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 11 CCDFLAT STIS/CCD ACCUM 52X2 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ LS-V-+22-25 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A LS-V-+22-25 2 STIS/CCD ACQ/PEA 52X0.1E1 MIRROR none none none none 1 N/A K LS-V-+22-25 3 STIS/CCD ACCUM 52X0.1E1 G430M 3680 none none none 1 1 121.0 S 16079( 4) - 01-May-2020 16:49:00 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ LS-V-+22-25 3 STIS/CCD ACCUM 52X0.1E1 G430M 3680 none none none 2 1 121.0 S WAVE 4 STIS/CCD ACCUM 52X0.2 G430M 3680 none none none none 1 N/A LS-V-+22-25 5 STIS/CCD ACCUM 52X0.1E1 G430M 3936 none none none 1 1 71.0 S LS-V-+22-25 5 STIS/CCD ACCUM 52X0.1E1 G430M 3936 none none none 2 1 71.0 S WAVE 6 STIS/CCD ACCUM 52X0.2 G430M 3936 none none none none 1 N/A LS-V-+22-25 7 STIS/CCD ACCUM 52X2E1 G430L 4300 none none none 1 1 66.0 S LS-V-+22-25 7 STIS/CCD ACCUM 52X2E1 G430L 4300 none none none 2 1 66.0 S LS-V-+22-25 7 STIS/CCD ACCUM 52X2E1 G430L 4300 none none none 3 1 66.0 S LS-V-+22-25 7 STIS/CCD ACCUM 52X2E1 G430L 4300 none none none 4 1 66.0 S WAVE 8 STIS/CCD ACCUM 52X0.2 G430L 4300 none none none none 1 N/A LS-V-+22-25 9 STIS/CCD ACCUM 52X2 G750L 7751 none none none 1 1 51.0 S LS-V-+22-25 9 STIS/CCD ACCUM 52X2 G750L 7751 none none none 2 1 51.0 S LS-V-+22-25 9 STIS/CCD ACCUM 52X2 G750L 7751 none none none 3 1 51.0 S LS-V-+22-25 9 STIS/CCD ACCUM 52X2 G750L 7751 none none none 4 1 51.0 S WAVE 10 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none none 1 N/A CCDFLAT 11 STIS/CCD ACCUM 52X2 G750L 7751 none none 1 none 1 N/A CCDFLAT 11 STIS/CCD ACCUM 52X2 G750L 7751 none none 2 none 1 N/A 16079( 4) - 01-May-2020 16:49:00 - [ 8] Visit: 03 (LB1 WFC3/IR GRISM/IMAGE) Visit Requirements: ORIENT 210D TO 255 D 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LS-V-+22-25 WFC3/IR MULTIAC GRISM256 G102 NSAMP=15, SAMP-SEQ=RAPID 1 DEF PATTERN 1 1-3 CUM (33.338 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 LS-V-+22-25 WFC3/IR MULTIAC GRISM256 G141 SAMP-SEQ=RAPID, NSAMP=15 1 DEF CUM (33.338 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LS-V-+22-25 WFC3/IR MULTIAC GRISM256 F130N SAMP-SEQ=RAPID, NSAMP=2 1 DEF (4.445 CUM S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LS-V-+22-25 WFC3/IR MULTIAC IRSUB256 F128N NSAMP=15, SAMP-SEQ=RAPID 1 DEF PATTERN 2 4-5 CUM (16.669 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 LS-V-+22-25 WFC3/IR MULTIAC IRSUB256 F130N NSAMP=15, SAMP-SEQ=RAPID 1 DEF CUM (16.669 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 1 none none none 1 N/A CUM LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 2 none none none 1 N/A CUM LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 3 none none none 1 N/A CUM LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 4 none none none 1 N/A CUM LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 5 none none none 1 N/A CUM LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 6 none none none 1 N/A CUM LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 7 none none none 1 N/A CUM LS-V-+22-25 1 WFC3/IR MULTIAC GRISM256 G102 8 none none none 1 N/A CUM LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 1 none none none 1 N/A CUM LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 2 none none none 1 N/A CUM 16079( 4) - 01-May-2020 16:49:00 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 3 none none none 1 N/A CUM LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 4 none none none 1 N/A CUM LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 5 none none none 1 N/A CUM LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 6 none none none 1 N/A CUM LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 7 none none none 1 N/A CUM LS-V-+22-25 2 WFC3/IR MULTIAC GRISM256 G141 8 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 1 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 2 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 3 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 4 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 5 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 6 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 7 none none none 1 N/A CUM LS-V-+22-25 3 WFC3/IR MULTIAC GRISM256 F130N 8 none none none 1 N/A CUM LS-V-+22-25 4 WFC3/IR MULTIAC IRSUB256 F128N 1 none none none 1 N/A CUM LS-V-+22-25 4 WFC3/IR MULTIAC IRSUB256 F128N 2 none none none 1 N/A CUM LS-V-+22-25 4 WFC3/IR MULTIAC IRSUB256 F128N 3 none none none 1 N/A CUM LS-V-+22-25 4 WFC3/IR MULTIAC IRSUB256 F128N 4 none none none 1 N/A CUM LS-V-+22-25 5 WFC3/IR MULTIAC IRSUB256 F130N 1 none none none 1 N/A CUM LS-V-+22-25 5 WFC3/IR MULTIAC IRSUB256 F130N 2 none none none 1 N/A CUM LS-V-+22-25 5 WFC3/IR MULTIAC IRSUB256 F130N 3 none none none 1 N/A CUM LS-V-+22-25 5 WFC3/IR MULTIAC IRSUB256 F130N 4 none none none 1 N/A CUM 16079( 4) - 01-May-2020 16:49:00 - [ 10] Summary Form for Proposal 16079 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 31X0.05NDC, 52X0.05, 52X0.1E1, 52X0.2, 52X2, 52X2E1, F28X50LP, GRISM256, IRSUB256 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS, STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA, WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/PEAK, MSMOFF, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=4, CR-SPLIT=NO, GRATING1=ALL, NSAMP=15, NSAMP=2, SAMP-SEQ=RAPID, SETOFFSET=RESTORE, SETOFFSET=ZERO, WAVECAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 210D TO 255 D, PATTERN 1 1-3, PATTERN 2 4-5 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F128N, F130N, G102, G140L, G141, G230L, G430L, G430M, G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, LS-V-+22-25, NONE, WAVE ------------------------------------------------------------------------------------------------------------------------------------