AGILE Observations of the Gravitational-wave Source GW170104

Journal Article · Sun Oct 01 00:00:00 EDT 2017 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/AA8224· OSTI ID:22654379

Verrecchia, F.; Pittori, C.; Lucarelli, F. ^[1]; Tavani, M.; Ursi, A.; Argan, A.; Evangelista, Y.; Minervini, G.; Cardillo, M.; Piano, G. ^[2]; Donnarumma, I. ^[3]; Bulgarelli, A.; Fuschino, F.; Labanti, C.; Fioretti, V. ^[4]; Marisaldi, M. ^[5]; Giuliani, A. ^[6]; Longo, F. ^[7]; Munar-Adrover, P. ^[8]; Pilia, M. ^[9] ; others, and

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1. ASI Space Science Data Center (SSDC), via del Politecnico, I-00133 Roma (Italy)
2. INAF-IAPS, via del Fosso del Cavaliere 100, I-00133 Roma (Italy)
3. ASI, via del Politecnico snc, I-00133 Roma (Italy)
4. INAF-IASF-Bologna, via Gobetti 101, I-40129 Bologna (Italy)
5. Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen (Norway)
6. INAF-IASF Milano, via E.Bassini 15, I-20133 Milano (Italy)
7. Dipartimento di Fisica, Università di Trieste and INFN, via Valerio 2, I-34127 Trieste (Italy)
8. Unitat de Física de les Radiacions, Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Spain)
9. INAF, Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy)

The LIGO/Virgo Collaboration (LVC) detected on 2017 January 4 a significant gravitational-wave (GW) event (now named GW170104). We report in this Letter the main results obtained from the analysis of hard X-ray and gamma-ray data of the AGILE mission that repeatedly observed the GW170104 localization region (LR). At the LVC detection time T {sub 0} AGILE observed about 36% of the LR. The gamma-ray imaging detector did not reveal any significant emission in the energy range 50 MeV–30 GeV. Furthermore, no significant gamma-ray transients were detected in the LR that was repeatedly exposed over timescales of minutes, hours, and days. We also searched for transient emission using data near T {sub 0} of the omnidirectional detector MCAL operating in the energy band 0.4–100 MeV. A refined analysis of MCAL data shows the existence of a weak event (that we call “E2”) with a signal-to-noise ratio of 4.4 σ lasting about 32 ms and occurring 0.46 ± 0.05 s before T {sub 0}. A study of the MCAL background and of the false-alarm rate of E2 leads to the determination of a post-trial significance between 2.4σ and 2.7σ for a temporal coincidence with GW170104. We note that E2 has characteristics similar to those detected from the weak precursor of GRB 090510. The candidate event E2 is worth consideration for simultaneous detection by other satellites. If associated with GW170104, it shows emission in the MeV band of a short burst preceding the final coalescence by 0.46 s and involving ∼10{sup −7} of the total rest mass energy of the system.

• OSTI ID: 22654379
• Journal Information: Astrophysical Journal Letters, Vol. 847, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COALESCENCE
DETECTION
EMISSION
GAMMA RADIATION
GEV RANGE
GRAVITATIONAL WAVES
HARD X RADIATION
MEV RANGE
PRECURSOR
REST MASS
SATELLITES
SIGNAL-TO-NOISE RATIO