Abbott, B. P.Abbott, R.Abbott, T. D.Abraham, SAcernese, FaustoAckley, K.Adams, C.Adhikari, Rana X.Adya, VaishaliAffeldt, C.Agathos, M.Altin, PaulEichholz, JohannesForsyth, PerryGrace, BenjaminHolland, NathanKijbunchoo, NutsineeMcClelland, DavidMcManus, DavidMcRae, TerryScott, Susan M.Shaddock, DanielSlagmolen, BramWard, RobertWette, KarlYap, Min Jet2020-10-252020-10-250556-2821http://hdl.handle.net/1885/213045We present the results of a search for long-duration gravitational-wave transients in the data from the Advanced LIGO second observation run; we search for gravitational-wave transients of 2–500 s duration in the 24–2048 Hz frequency band with minimal assumptions about signal properties such as waveform morphologies, polarization, sky location or time of occurrence.The authors gratefully acknowledge the support of the United States National Science Foundation (NSF) for the construction and operation of the LIGO Laboratory and Advanced LIGO as well as the Science and Technology Facilities Council (STFC) of the United Kingdom, the Max-Planck-Society (MPS), and the State of Niedersachsen/Germany for support of the construction of Advanced LIGO and construction and operation of the GEO600 detector. Additional support for Advanced LIGO was provided by the Australian Research Councilapplication/pdfen-AU© 2019 American Physical Society201910.1103/PhysRevD.99.1040332022-04-24