Giant burst of methanol maser in S255IR-NIRS3

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dc.contributor.author Szymczak, Marian
dc.contributor.author Olech, Mateusz
dc.contributor.author Wolak, Paweł
dc.contributor.author Gerard, Eric
dc.contributor.author Bartkiewicz, Anna
dc.date.accessioned 2020-10-06T14:11:48Z
dc.date.available 2020-10-06T14:11:48Z
dc.date.issued 2018
dc.identifier.citation Astronomy and Astrophysics vol. 617, 2018, A80, pp.1-9.
dc.identifier.issn 0004-6361
dc.identifier.issn 1432-0746 (online)
dc.identifier.other 10.1051/0004-6361/201833443
dc.identifier.uri http://repozytorium.umk.pl/handle/item/6381
dc.description.abstract Context.High-mass young stellar objects (HMYSOs) can undergo accretion episodes that strongly affect the star evolution, the dynamics of the disk, and its chemical evolution. Recently reported extraordinary bursts in the methanol maser emission may be the observational signature of accretion events in deeply embedded HMYSOs. Aims.We analyze the light curve of 6.7GHz methanol masers in S255IR-NIRS3 during the 2015-2016 burst. Methods.8.5-yr monitoring data with an average sampling interval of 5 days were obtained with the Torun 32 m radio telescope. Archival data were added, extending the time series to ~27 yr. Results.The maser emission showed moderate (25-30%) variability on timescales of months to years over ~23 yr since its discovery.The main burst was preceded by a 1 yr increase of the total flux density by a factor of 2.5, then it grew by a factor of 10 over ~0.4 yr and declined by a factor of 8 during the consecutive 2.4 yr. The peak maser luminosity was a factor of 24.5 higher than the pre-burst quiescent value. The light curves of individual features showed considerable diversity but indicated a general trend of suppression of the maser emission at blueshifted (<4.7 km/s) velocities when the redshifted emission rapidly grew and new emission features appeared at velocities >5.8km/s. This new emission provided a contribution of about 80% to the maser luminosity around the peak of the burst. The duration of the burst at the extreme redshifted velocities of 7.1–-8.7km/s was from 0.9 to 1.9 yr, and its lower limit for the other features was ~3.9 yr. Conclusions.The onset of the maser burst exactly coincides with that of the infrared burst estimated from the motion of the light echo. This strongly supports the radiative pumping scheme of the maser transition. The growth of the maser luminosity is the result of an increasing volume of gas where the maser inversion is achieved.
dc.description.sponsorship NCN
dc.language.iso eng
dc.publisher EDP Sciences
dc.subject masers
dc.subject stars: massive
dc.subject stars: formation
dc.subject stars: individual: S255IR-NIRS3
dc.subject ISM: molecules
dc.title Giant burst of methanol maser in S255IR-NIRS3
dc.type info:eu-repo/semantics/article

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