18083( 4) - 05-Sep-2025 19:15:33 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18083 Version: 4 Check-in Time: 05-Sep-2025 19:15:33 STScI Edit Number: 2 Title Extreme-UV to Near-UV Spectroscopic Exploration of the Lensed Quasar PG 1115+080 ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dra. Carina Fian Universidad de Valencia, Observatorio Y Astronomico CoI: Prof. Doron Chelouche University of Haifa N CoI: Dr. Shai Kaspi Tel Aviv University - Wise Observatory N CoI: Prof. Jose A. Munoz Universidad de Valencia, Observatorio N Astronomico CoI: Prof. Adi Zitrin Ben-Gurion University of the Negev N CoI: Dr. David V. Bowen Princeton University N ------------------------------------------------------------------------------------ Abstract Emerging evidence indicates that traditional models of black hole accretion are incomplete - quasar accretion disks appear systematically larger than predicted, a discrepancy that challenges our understanding of disk structure, black hole growth, and the use of quasars as standard candles. Gravitational microlensing has been proven successful in studying quasar interiors that remain unresolvable by conventional imaging techniques. The gravitationally lensed quasar PG 1115+080 offers an ideal natural experiment; its fold-caustic configuration produces a close image pair that, through microlensing effects, serves as a "zoom" on the smallest emission regions. We propose a small HST/STIS program designed to obtain continuous spectroscopy from the extreme ultraviolet (UV) to the near UV. This extensive spectral coverage will probe the innermost emission regions of the quasar - capturing the hottest accretion disk zones near the Lyman limit and linking them to the extended near UV continuum. Our observations will cover a wealth of emission features, including prominent broad lines and several little-explored lines in the extreme/far UV, thereby offering new insights into the ionization structure and gas kinematics of the broad-line region. By measuring the wavelength-dependent microlensing magnification of the continuum, we will determine the disk size as a function of wavelength - a critical test of thin-disk theory. These observations are especially timely, as HST/STIS is currently the only facility capable of accessing the extreme and far UV regimes. Without it, this spectral window, and the physics it probes, will remain out of reach. ------------------------------------------------------------------------------------ Observations Description ------------------------ Target & Goal: Resolved STIS spectroscopy of PG 1115+080 to extract separate spectra of images A1 and A2. Orient: We require an ORIENT that puts A1 and A2 along the slit with > 0.40 arcsec separation. Acquisition. One STIS/CCD ACQ (POINT) at the start of each visit. Scheduling. Visits limited to short contiguous blocks (2-5 orbits) to avoid MAMA SAA conflicts. 18083( 4) - 05-Sep-2025 19:15:33 - [ 2] FUV-/NUV-MAMA Spectroscopy: Time-Tag; Buffer-Time: 4/5 x ETC. CCD Spectroscopy - G430L & G750L: Accum; we add fringe flats immediately after the red science with no grating move. ------------------------------------------------------------------------------------ 18083( 4) - 05-Sep-2025 19:15:33 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 QSO-B1115+08 GALAXY, GRAVITATIONAL RA=11H18M16.9531S, J2000 Z = V = 16.90 +/- 0.11 0A LENS, QSO, QUASAR DEC=+07D45'58.16" 1.722 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) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 18083( 4) - 05-Sep-2025 19:15:33 - [ 4] Visit: 01 (Visit 1: 5 Orbits) Visit Requirements: ORIENT 253.7D TO 276.9 D; BEFORE 19-FEB-2026:00:00:00 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 QSO-B1115+0 STIS/CCD ACQ F28X50LP MIRROR 1 20 S (20 80A S) ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO-B1115+0 STIS/FUV TIME-TA 52X2 G140L 1425 BUFFER-TIME=1265 1 1952 S 80A -MAMA G (1952 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO-B1115+0 STIS/FUV TIME-TA 52X2 G140L 1425 BUFFER-TIME=1265 1 2569 S 80A -MAMA G (2569 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 QSO-B1115+0 STIS/FUV TIME-TA 52X2 G140L 1425 BUFFER-TIME=1265 1 2529 S 80A -MAMA G (2529 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 QSO-B1115+0 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1420 1 2544 S 80A -MAMA G (2544 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 QSO-B1115+0 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1420 1 2544 S 80A -MAMA G (2544 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 | ------------------------------------------------------------------------------------------------------------------------------------ QSO-B1115+080A 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A QSO-B1115+080A 2 STIS/FUV TIME-TA 52X2 G140L 1425 none none none none 1 N/A -MAMA G QSO-B1115+080A 3 STIS/FUV TIME-TA 52X2 G140L 1425 none none none none 2 N/A -MAMA G QSO-B1115+080A 4 STIS/FUV TIME-TA 52X2 G140L 1425 none none none none 3 N/A -MAMA G QSO-B1115+080A 5 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 4 N/A -MAMA G QSO-B1115+080A 6 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 5 N/A -MAMA G 18083( 4) - 05-Sep-2025 19:15:33 - [ 5] Visit: 02 (Visit 2: 2 Orbits) Visit Requirements: SAME ORIENT AS 01; AFTER 01 BY 0 D TO 3 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 QSO-B1115+0 STIS/CCD ACQ F28X50LP MIRROR 1 20 S (20 80A S) ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO-B1115+0 STIS/CCD ACCUM 52X2 G430L 4300 1 1986 S 80A (1986 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO-B1115+0 STIS/CCD ACCUM 52X2 G750L 7751 1 2455 S 80A (2455 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 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 | ------------------------------------------------------------------------------------------------------------------------------------ QSO-B1115+080A 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A QSO-B1115+080A 2 STIS/CCD ACCUM 52X2 G430L 4300 none none none 1 1 N/A QSO-B1115+080A 2 STIS/CCD ACCUM 52X2 G430L 4300 none none none 2 1 N/A QSO-B1115+080A 3 STIS/CCD ACCUM 52X2 G750L 7751 none none none 1 2 N/A QSO-B1115+080A 3 STIS/CCD ACCUM 52X2 G750L 7751 none none none 2 2 N/A CCDFLAT 4 STIS/CCD ACCUM 52X2 G750L 7751 none none 1 none 2 N/A CCDFLAT 4 STIS/CCD ACCUM 52X2 G750L 7751 none none 2 none 2 N/A 18083( 4) - 05-Sep-2025 19:15:33 - [ 6] Visit: 03 (Visit 3: 5 Orbits) Visit Requirements: ORIENT 253.7D TO 276.9 D; AFTER 19-FEB-2026:00:00:00 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 QSO-B1115+0 STIS/CCD ACQ F28X50LP MIRROR 1 20 S (20 80A S) ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO-B1115+0 STIS/FUV TIME-TA 52X2 G140L 1425 BUFFER-TIME=1265 1 1952 S 80A -MAMA G (1952 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO-B1115+0 STIS/FUV TIME-TA 52X2 G140L 1425 BUFFER-TIME=1265 1 2569 S 80A -MAMA G (2569 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 QSO-B1115+0 STIS/FUV TIME-TA 52X2 G140L 1425 BUFFER-TIME=1265 1 2529 S 80A -MAMA G (2529 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 QSO-B1115+0 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1420 1 2544 S 80A -MAMA G (2544 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 QSO-B1115+0 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1420 1 2544 S 80A -MAMA G (2544 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 | ------------------------------------------------------------------------------------------------------------------------------------ QSO-B1115+080A 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A QSO-B1115+080A 2 STIS/FUV TIME-TA 52X2 G140L 1425 none none none none 1 N/A -MAMA G QSO-B1115+080A 3 STIS/FUV TIME-TA 52X2 G140L 1425 none none none none 2 N/A -MAMA G QSO-B1115+080A 4 STIS/FUV TIME-TA 52X2 G140L 1425 none none none none 3 N/A -MAMA G QSO-B1115+080A 5 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 4 N/A -MAMA G QSO-B1115+080A 6 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 5 N/A -MAMA G 18083( 4) - 05-Sep-2025 19:15:33 - [ 7] Visit: 04 (Visit 4: 5 Orbits) Visit Requirements: SAME ORIENT AS 03; AFTER 03 BY 0 D TO 3 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 QSO-B1115+0 STIS/CCD ACQ F28X50LP MIRROR 1 20 S (20 80A S) ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO-B1115+0 STIS/CCD ACCUM 52X2 G430L 4300 1 1986 S 80A (1986 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO-B1115+0 STIS/CCD ACCUM 52X2 G750L 7751 1 2455 S 80A (2455 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 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 | ------------------------------------------------------------------------------------------------------------------------------------ QSO-B1115+080A 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A QSO-B1115+080A 2 STIS/CCD ACCUM 52X2 G430L 4300 none none none 1 1 N/A QSO-B1115+080A 2 STIS/CCD ACCUM 52X2 G430L 4300 none none none 2 1 N/A QSO-B1115+080A 3 STIS/CCD ACCUM 52X2 G750L 7751 none none none 1 2 N/A QSO-B1115+080A 3 STIS/CCD ACCUM 52X2 G750L 7751 none none none 2 2 N/A CCDFLAT 4 STIS/CCD ACCUM 52X2 G750L 7751 none none 1 none 2 N/A CCDFLAT 4 STIS/CCD ACCUM 52X2 G750L 7751 none none 2 none 2 N/A 18083( 4) - 05-Sep-2025 19:15:33 - [ 8] Summary Form for Proposal 18083 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1265, BUFFER-TIME=1420 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 0 D TO 3 D, AFTER 03 BY 0 D TO 3 D, AFTER 19-FEB-2026:00:00:00, BEFORE 19-FEB-2026:00:00:00, ORIENT 253.7D TO 276.9 D, SAME ORIENT AS 01, SAME ORIENT AS 03 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, G430L, G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, QSO-B1115+080A ------------------------------------------------------------------------------------------------------------------------------------