AGILE OBSERVATIONS OF THE GRAVITATIONAL-WAVE EVENT GW150914

Journal Article · Fri Jul 01 00:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/825/1/L4· OSTI ID:22654197

Tavani, M.; Donnarumma, I.; Argan, A.; Monte, E. Del; Evangelista, Y.; Piano, G.; Munar-Adrover, P. ^[1]; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Antonelli, L. A. ^[2]; Bulgarelli, A.; Marisaldi, M.; Fioretti, V.; Zoli, A. ^[3]; Giuliani, A.; Caraveo, P. ^[4]; Trois, A. ^[5]; Barbiellini, G. ^[6]; others, and

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1. INAF-IAPS, via del Fosso del Cavaliere 100, I-00133 Roma (Italy)
2. ASI Science Data Center (ASDC), Via del Politecnico, I-00133 Roma (Italy)
3. INAF-IASF-Bologna, Via Gobetti 101, I-40129 Bologna (Italy)
4. INAF-IASF Milano, via E.Bassini 15, I-20133 Milano (Italy)
5. INAF, Osservatorio Astronomico di Cagliari, Poggio dei Pini, strada 54, I-09012 Capoterra (Italy)
6. Dip. di Fisica, Universita’ di Trieste and INFN, Via Valerio 2, I-34127 Trieste (Italy)

We report the results of an extensive search through the AGILE data for a gamma-ray counterpart to the LIGO gravitational-wave (GW) event GW150914. Currently in spinning mode, AGILE has the potential of cover 80% of the sky with its gamma-ray instrument, more than 100 times a day. It turns out that AGILE came within a minute of the event time of observing the accessible GW150914 localization region. Interestingly, the gamma-ray detector exposed ∼65% of this region during the 100 s time intervals centered at −100 and +300 s from the event time. We determine a 2 σ flux upper limit in the band 50 MeV–10 GeV, UL = 1.9 × 10{sup −8} erg cm{sup −2} s{sup −1}, obtained ∼300 s after the event. The timing of this measurement is the fastest ever obtained for GW150914, and significantly constrains the electromagnetic emission of a possible high-energy counterpart. We also carried out a search for a gamma-ray precursor and delayed emission over five timescales ranging from minutes to days: in particular, we obtained an optimal exposure during the interval −150/−30 s. In all these observations, we do not detect a significant signal associated with GW150914. We do not reveal the weak transient source reported by Fermi -GBM 0.4 s after the event time. However, even though a gamma-ray counterpart of the GW150914 event was not detected, the prospects for future AGILE observations of GW sources are decidedly promising.

• OSTI ID: 22654197
• Journal Information: Astrophysical Journal Letters, Vol. 825, Issue 1; 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
EMISSION
GAMMA RADIATION
GEV RANGE
GRAVITATIONAL WAVES
INTERFERENCE
MEV RANGE
PRECURSOR
SKY