15835( 3) - 30-Jul-2020 18:10:39 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15835 Version: 3 Check-in Time: 30-Jul-2020 18:10:39 STScI Edit Number: 0 Title Near-Ultraviolet Follow-up of the X-ray-detected Warm-Hot Intergalactic Medium Toward 1ES 1553+113 ------------------------------------------------------------------------------------ Type Cycle GO 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Sowgat Muzahid Leibniz-Institut fur Astrophysik Potsdam Y (AIP) CoI: Dr. Sean Johnson University of Michigan Y CoI: Prof. Joop Schaye Universiteit Leiden N CoI: Prof. Jane C. Charlton The Pennsylvania State University N CoI: Prof. Hsiao-Wen Chen University of Chicago N CoI: Dr. Anand Narayanan Indian Institute of Space Science and N Technology CoI: Ms. Nastasha Wijers Universiteit Leiden N CoI: Dr. John S. Mulchaey Carnegie Institution of Washington N ------------------------------------------------------------------------------------ Abstract One of the strengths of modern cosmology is that the cosmic baryon density predicted by Big Bang nucleosynthesis precisely matches the measured value from the cosmic microwave background. At high redshift the vast majority of these baryons are found in the photoionized intergalactic medium. However, cosmological simulations of structure formation predict that a substantial portion of these baryons will be shock heated into the elusive warm-hot intergalactic medium (WHIM) as the universe evolves. Confirmation of these predictions through observations of the WHIM and measurements of its physical state provide a sensitive test of our understanding of the growth of structure in the universe. Recently, Nicastro et al. (2018) reported the first detections of two intervening OVII absorption systems in the X-ray spectrum of the blazar 1ES 1553+113. These systems are thought to be arising from the WHIM with a temperature of ~10^6 K. Nevertheless, the redshift of the blazar is not known with adequate precision, which makes the origin(s) of the OVII bearing gas and its contribution to the cosmic baryon density highly uncertain. Here we propose to obtain NUV spectra of the blazar using the COS G185M grating. The proposed spectra will enable us to detect intervening Lyman alpha absorbers with log N(HI)/cm-2 > 13.0 from z = 0.45 - 0.7. The stringent lower (upper) limit on the blazar's redshift to be obtained from the presence (absence) of any such absorber will be crucial to validate or rule out the claim of potentially solving the so called "missing baryons problem". ------------------------------------------------------------------------------------ Observations Description ------------------------ In order to place stringent constraints on the blazar (1ES1553+113) redshift and determine whether the O VII absorber at z = 0.4339 is in the blazar's host environment, we will obtain NUV COS spectra to search for intervening IGM HI Lya lines at z > 0.41. Contiguous spectral coverage in the NUV from 1767 to 2068 Angstrom with a S/N per resolution element of 12 will enable us to detect intervening IGM Lya absorption systems with log N(HI) > 13 from z = 0.45 to 15835( 3) - 30-Jul-2020 18:10:39 - [ 2] 0.7. Based on the expected number of such HI systems per unit redshift from Danforth et al. (2016), we expect to detect 10 Lya lines per dz = 0.1 interval. Non-detection of Lya at z > 0.45 in combination with our deep and highly complete galaxy redshift survey in the field would indicate that the blazar is in the same environment as the WHIM candidate at z=0.4339. Based on the COS ETC, obtaining the desired spectral coverage and S/N will require observations with COS G185M gratings with central wavelength settings of 1882, 1913, 1941, and 1953, each observed for one orbit for a total of four orbits of COS NUV spectroscopy. We will split each central wavelength setting into four FP-POS positions as recommended to minimize flat fielding errors. Moreover, as per the instructions after the gyro failure, we will complete the total allocated 4 orbits in two visits. Since the co-ordinates of the target are obtain from GAIA with an accuracy better than 0.02", we will directly use PEAKXD followed by PEAKD for acquisition. For the flux observed in the existing COS spectrum (F(1300) = 1.5e-14), ACQ/IMAGE is a viable option. However, it exceeds the bright limit if the flux is increased by a factor of 2.5 (1 mag) owing to unexpected flare. Therefore, we adopt the spectroscopic acquisition for instruments' safety. We used the existing archival COS spectrum of the blazar for calculating the exposure time for spectroscopic acquisition (COS.sa.1366483). Impact of reduced-gyro operations: There are no significant impact of the reduced-gyro mode (RGM) operations except for an increased target acquisition time of 2 minutes. ------------------------------------------------------------------------------------ 15835( 3) - 30-Jul-2020 18:10:39 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 QSO-B1553+11 GALAXY, BL LAC RA=15H55M43.0440S +/- 0.02", J2000 V = 14.57 G=14, FUV=16.3, NUV=15.6, 3 DEC=+11D11'24.37" +/- 0.02" F(1300) = 1.5e-14 from HST/COS Reference Frame: ICRS Extended: NO Comments: Co-ordinates are from GAIA ------------------------------------------------------------------------------------------------------------------------------------ 15835( 3) - 30-Jul-2020 18:10:39 - [ 4] Visit: 01 (QSO-B1553+113-VISIT-01) 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 QSO-B1553+1 COS/FUV ACQ/PEA PSA G130M 1291 SEGMENT=BOTH, NUM-POS=3, 1 5 S (5 S) 13 KXD STEP-SIZE=1.3, CENTER=FLUX-WT ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO-B1553+1 COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=5, STEP-SIZE=0.9, 1 5 S (5 S) 13 KD SEGMENT=BOTH, CENTER=FLUX-WT-FLR ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1882 FP-POS=1, BUFFER-TIME=1561 1 456 S (456 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 4 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1882 FP-POS=2, BUFFER-TIME=1561 1 454 S (454 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 5 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1882 FP-POS=3, BUFFER-TIME=1561 1 454 S (454 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 6 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1882 FP-POS=4, BUFFER-TIME=1561 1 454 S (454 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 7 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1913 FP-POS=1, BUFFER-TIME=1561 1 633 S (633 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 8 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1913 FP-POS=2, BUFFER-TIME=1561 1 632 S (632 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 9 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1913 FP-POS=3, BUFFER-TIME=1561 1 632 S (632 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 10 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1913 FP-POS=4, BUFFER-TIME=1561 1 632 S (632 13 G 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-B1553+113 1 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD QSO-B1553+113 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD 15835( 3) - 30-Jul-2020 18:10:39 - [ 5] 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-B1553+113 3 COS/NUV TIME-TA PSA G185M 1882 none none none none 1 N/A G QSO-B1553+113 4 COS/NUV TIME-TA PSA G185M 1882 none none none none 1 N/A G QSO-B1553+113 5 COS/NUV TIME-TA PSA G185M 1882 none none none none 1 N/A G QSO-B1553+113 6 COS/NUV TIME-TA PSA G185M 1882 none none none none 1 N/A G QSO-B1553+113 7 COS/NUV TIME-TA PSA G185M 1913 none none none none 2 N/A G QSO-B1553+113 8 COS/NUV TIME-TA PSA G185M 1913 none none none none 2 N/A G QSO-B1553+113 9 COS/NUV TIME-TA PSA G185M 1913 none none none none 2 N/A G QSO-B1553+113 10 COS/NUV TIME-TA PSA G185M 1913 none none none none 2 N/A G 15835( 3) - 30-Jul-2020 18:10:39 - [ 6] Visit: 02 (QSO-B1553+113-VISIT-02) 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 QSO-B1553+1 COS/FUV ACQ/PEA PSA G130M 1291 SEGMENT=BOTH, NUM-POS=3, 1 5 S (5 S) 13 KXD STEP-SIZE=1.3, CENTER=FLUX-WT ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO-B1553+1 COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=5, STEP-SIZE=0.9, 1 5 S (5 S) 13 KD SEGMENT=BOTH, CENTER=FLUX-WT-FLR ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=1, BUFFER-TIME=1561 1 455 S (455 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 4 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=2, BUFFER-TIME=1561 1 455 S (455 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 5 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=3, BUFFER-TIME=1561 1 454 S (454 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 6 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=4, BUFFER-TIME=1561 1 454 S (454 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 7 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1941 FP-POS=1, BUFFER-TIME=1561 1 633 S (633 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 8 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1941 FP-POS=2, BUFFER-TIME=1561 1 632 S (632 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 9 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1941 FP-POS=3, BUFFER-TIME=1561 1 632 S (632 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 10 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1941 FP-POS=4, BUFFER-TIME=1561 1 632 S (632 13 G 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-B1553+113 1 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD QSO-B1553+113 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD 15835( 3) - 30-Jul-2020 18:10:39 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ QSO-B1553+113 3 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G QSO-B1553+113 4 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G QSO-B1553+113 5 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G QSO-B1553+113 6 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G QSO-B1553+113 7 COS/NUV TIME-TA PSA G185M 1941 none none none none 2 N/A G QSO-B1553+113 8 COS/NUV TIME-TA PSA G185M 1941 none none none none 2 N/A G QSO-B1553+113 9 COS/NUV TIME-TA PSA G185M 1941 none none none none 2 N/A G QSO-B1553+113 10 COS/NUV TIME-TA PSA G185M 1941 none none none none 2 N/A G 15835( 3) - 30-Jul-2020 18:10:39 - [ 8] Visit: 52 (QSO-B1553+113-VISIT-52) 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 QSO-B1553+1 COS/FUV ACQ/PEA PSA G130M 1291 SEGMENT=BOTH, NUM-POS=3, 1 5 S (5 S) 13 KXD STEP-SIZE=1.3, CENTER=FLUX-WT ------------------------------------------------------------------------------------------------------------------------------------ 2 QSO-B1553+1 COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=5, STEP-SIZE=0.9, 1 5 S (5 S) 13 KD SEGMENT=BOTH, CENTER=FLUX-WT-FLR ------------------------------------------------------------------------------------------------------------------------------------ 3 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=1, BUFFER-TIME=1561 1 455 S (455 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 4 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=2, BUFFER-TIME=1561 1 455 S (455 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 5 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=3, BUFFER-TIME=1561 1 454 S (454 13 G S) ------------------------------------------------------------------------------------------------------------------------------------ 6 QSO-B1553+1 COS/NUV TIME-TA PSA G185M 1953 FP-POS=4, BUFFER-TIME=1561 1 454 S (454 13 G 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-B1553+113 1 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD QSO-B1553+113 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD QSO-B1553+113 3 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G QSO-B1553+113 4 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G QSO-B1553+113 5 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G QSO-B1553+113 6 COS/NUV TIME-TA PSA G185M 1953 none none none none 1 N/A G 15835( 3) - 30-Jul-2020 18:10:39 - [ 9] Summary Form for Proposal 15835 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1561, CENTER=FLUX-WT, CENTER=FLUX-WT-FLR, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, NUM-POS=3, NUM-POS=5, SEGMENT=BOTH, STEP-SIZE=0.9, STEP-SIZE=1.3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G185M ------------------------------------------------------------------------------------------------------------------------------------ Target Names QSO-B1553+113 ------------------------------------------------------------------------------------------------------------------------------------