We present a systematic search for short-duration gamma-ray bursts (GRBs) in the local Universe based on 14 yr of observations with the Neil Gehrels Swift Observatory. We cross-correlate the GRB positions with the GLADE catalogue of nearby galaxies, and find no event at a distance ≲100 Mpc and four plausible candidates in the range 100 Mpc ≲ D ≲ 200 Mpc. Although affected by low statistics, this number is higher than the one expected for chance alignments to random galaxies, and possibly suggests a physical association between these bursts and nearby galaxies. By assuming a local origin, we use these events to constrain the range of properties for X-ray counterparts of neutron star mergers. Optical upper limits place tight constraints on the onset of a blue kilonova, and imply either low masses (≲ 10−3 M☉) of lanthanide-poor ejecta or unfavorable orientations (θobs ≳ 30 deg). Finally, we derive that the all-sky rate of detectable short GRBs within 200 Mpc is 1.3+1.7−0.8 yr−1 (68 per cent confidence interval), and discuss the implications for the GRB outflow structure. If these candidates are instead of cosmological origin, we set a upper limit of ≲2.0 yr−1 (90 per cent confidence interval) to the rate of nearby events detectable with operating gamma-ray observatories, such as Swift and Fermi.
Bibliographical noteFunding Information:
We thank Brad Cenko and Antonio Galvan-Gamez for the help with data analysis and the useful discussions. This work was supported in part by the National Aeronautics and Space Administration through grant NNX10AF62G issued through the Astrophysics Data Analysis Program. This work was performed in part at Aspen Center for Physics, which is supported by National Science Foundation grant PHY-1607611. The research of PB was funded by the Gordon and Betty Moore Foundation through Grant GBMF5076. This research uses services or data provided by the Science Data Archive at National Optical Astronomy Observatory (NOAO). NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation. This publication made use of data products supplied by the UK Swift Science Data Centre at the University of Leicester, and from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration.
© 2020 The Author(s)
- Gamma-ray bursts
- Gravitational waves
- Nuclear reactions
- Stars: neutron