17897( 3) - 06-Feb-2025 17:22:42 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17897 Version: 3 Check-in Time: 06-Feb-2025 17:22:42 STScI Edit Number: 1 Title Community Discovery Program: CXO/VLA/HST observations of GW-detected compact mergers in O4b ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Sergio Campana INAF - Osservatorio Astronomico di Brera Y CoI: Prof. Daryl Haggard McGill University Y CoI: Dr. Raffaella Margutti University of California - Berkeley N CoI: Prof. Peter G. Jonker Radboud University Nijmegen N CoI: Dr. Wen-fai Fong Northwestern University N CoI: Dr. Maria Grazia Bernardini INAF - Osservatorio Astronomico di Brera N CoI: Dr. Giancarlo Ghirlanda INAF - Osservatorio Astronomico di Brera N CoI: Dr. Paolo D'Avanzo N CoI: Dr. Andrea Bulgarelli INAF - Osservatorio di Astrofisica e N Scienza dello Spazio CoI: Dr. Andrea Melandri INAF - Osservatorio Astronomico di Brera N CoI: Prof. Andrew James Levan Radboud University Nijmegen N CoI: Prof. Edo Berger Harvard University N CoI: Mr. Itai Sfaradi University of California - Berkeley N CoI: Nayana AJ University of California - Berkeley N CoI: Eli Wiston University of California - Berkeley N CoI: Prof. Ryan Chornock University of California - Berkeley N CoI: Natalie LeBaron University of California - Berkeley N CoI: Mr. Daniel Brethauer University of California - Berkeley N CoI: Dr. Om Sharan Salafia INAF - Osservatorio Astronomico di Brera N ------------------------------------------------------------------------------------ Abstract The joint detection of GWs and light from the neutron star (NS) merger GW 170817 ushered us into a new era. Deep X-ray observations of GW 170817 constrained the structural properties of a relativistic outflow launched by an NS merger for the first time. After these landmark discoveries, the frontier is now to map the X-ray properties of a population of sources. We propose to exploit the unique capabilities of XMM-Newton to constrain the broad-band properties of very nearby NS-bearing mergers, selected from LVKC-O4 GW triggers or electromagnetically identified kilonovae. Our immediate goals are: (i) map the diversity of emission from NS mergers, (ii) test the nature of the remnant object, (iii) determine if all mergers launch a jet, and (iv) enable the first X-ray detections of NS-BH mergers. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our detailed follow-up strategy is as follows: [I] Prompt-bright observation (< 2d), trigger if: (i) detection of a bright (> 5x10-13 erg s-1 cm-2, 0.5-10 keV) X-ray counterpart, OR (ii) bright blue/UV-optical counterpart (V < 18); then trigger one 60 ks XMM-Newton observation within 2d to exploit EPIC (and if bright) RGS science, to search for soft components and absorption studies, and OM with u(the most efficient) filter in timing mode (> 150, 000 counts). No 17897( 3) - 06-Feb-2025 17:22:42 - [ 2] particular feasibility is needed. The event should be bright given the triggering criteria and the selected observing modes should avoid pile-up. [II] Follow-up observations at t > 10d if: (i) discovery and localisation of an EM (gamma-rays, X-rays, optical, radio) of a GW-detected NS-bearing event, OR (ii) EM-identified kilonova then (indicatively) we will execute three observations. (1) before peak: 60ks XMM-Newton/EPIC/FF/Thin + HST F606W (1orb) + VLA (2hr@6GHz+2hr@10GHz); (2) at the peak: 60ks XMM-Newton/EPIC/FF/Thin + HST F606W (1orb) + VLA (2hr@6GHz+2hr@10GHz) + 60ks NuSTAR; (3) after peak: 100ks XMM-Newton/EPIC/FF/Thin + HST F606W (1orb) + VLA (2hr@6GHz+2hr@10GHz). For the VLA, we require reaching 3sigma limits of 10 microJy (1.5 hr on-source, 2 hr total) in C-band. If detected, we will trigger another 2-hr observation at 10 GHz to constrain the spectral slope. In one orbit observation HST can reach F606W ~27 mag. HST and VLA will be mandatory to firmly constrain the spectral slope and search for cooling frequency breaks in the spectrum. NuSTAR will detect the afterglow if it is brighter than >10-13 erg s-1 cm-2 (0.5-10 keV). This will allow us to extend the wavelength range at peak on a broader wavelength scale. Our total request is 280 ks XMM-Newton time, 3 orbits of HST, 12 hr of VLA and 60 ks of NuSTAR. ------------------------------------------------------------------------------------ 17897( 3) - 06-Feb-2025 17:22:42 - [ 3] TARGET LIST Generic Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Selection Criteria | Flux data No | Name | Description | | ------------------------------------------------------------------------------------------------------------------------------------ 1 GW-1 STAR, GAMMA RAY GW TRIGGER V = 28 BURSTER, NEUTRON STAR Comments: Electromagnetic counterpart of a GW trigger ------------------------------------------------------------------------------------------------------------------------------------ 17897( 3) - 06-Feb-2025 17:22:42 - [ 4] Visit: 01 (GW-1) Visit Requirements: TOO RESPONSE TIME 15.0D 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 GW-1 WFC3/UVI ACCUM UVIS F606W 1 2400 S POS TARG 0, 0 S see below (2617 S) Comments: TOO observation ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ GW-1 1 WFC3/UVI ACCUM UVIS F606W none none none none 1 2617.0 S S 17897( 3) - 06-Feb-2025 17:22:42 - [ 5] Visit: 02 (GW-1) Visit Requirements: TOO RESPONSE TIME 100.0D 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 GW-1 WFC3/UVI ACCUM UVIS F606W 1 2400 S S see below (2617 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 | ------------------------------------------------------------------------------------------------------------------------------------ GW-1 1 WFC3/UVI ACCUM UVIS F606W none none none none 1 2617.0 S S 17897( 3) - 06-Feb-2025 17:22:42 - [ 6] Visit: 03 (GW-1) Visit Requirements: TOO RESPONSE TIME 200.0D 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 GW-1 WFC3/UVI ACCUM UVIS F606W 1 2400 S S see below (2617 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 | ------------------------------------------------------------------------------------------------------------------------------------ GW-1 1 WFC3/UVI ACCUM UVIS F606W none none none none 1 2617.0 S S 17897( 3) - 06-Feb-2025 17:22:42 - [ 7] Summary Form for Proposal 17897 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG 0, 0, TOO RESPONSE TIME 100.0D, TOO RESPONSE TIME 15.0D, TOO RESPONSE TIME 200.0D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GW-1 ------------------------------------------------------------------------------------------------------------------------------------