Ten years since the NGC 6334I-MM1 accretion outburst: the impact on its environment
Year: 2026
Type: article
Abstract: Ten years on, flaring continues in masers associated with NGC 6334I-MM1. Methanol and hydroxyl masers are nearing quiescent values, but water features remain elevated. Several more 1.665 GHz hydroxyl masers, notably, that flared during the accretion event in NGC 6334I-MM1, are identified and presented. Some hydroxyl masers appear to have been active prior to the 2015 event. Possible explanations are discussed. The radial infrared expansion speed during the accretion event is estimated to be ~1.8 AU d−1. However, the expansion speed along the North-South outflow is about ten times faster (~18 AU d−1). The maser flaring activity illuminated clumpy structure in NGC 6334I-MM1. Quasi-periodicity is reported after the 2015 accretion event in the total integrated 12.2 GHz methanol emission, predominantly in v12.2 = [ − 12.0, −9.9] km s−1, after the accretion event in NGC 6334I-MM1. It is not certain if the periodic masers are located in NGC 6334I-MM1, -MM2, or -MM3. The magnetic field, measured from the Zeeman splitting of two ground state hydroxyl lines, undergoes changes before and after the flare.
Institutions: Xinjiang Astronomical Observatory, Hartebeesthoek Radio Astronomy Observatory, University of Chinese Academy of Sciences, Open University of Tanzania, Astronomical Observatory of Capodimonte, National Institute for Astrophysics, Netherlands Institute for Radio Astronomy, University of South Africa, National Radio Astronomy Observatory, University of Virginia, University of Nigeria, National Astronomical Observatory of Japan, Thüringer Landessternwarte Tautenburg, University of Helsinki
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Funder: Chinese Academy of Sciences
OpenAlex ID: W7213606339