The Extraordinary Outburst in the Massive Protostellar System NGC6334I-MM1: Spatio-kinematics of Water Masers during a Contemporaneous Flare Event

Abstract

Following an eruptive accretion event in NGC6334I-MM1, flares in the various maser species, including water masers, were triggered. We report the observed relative proper motion of the highly variable water masers associated with the massive star-forming region, NGC6334I. High velocity H${}_2$O maser proper motions were detected in 5 maser clusters, CM2-W2 (bow-shock structure), MM1-W1, MM1-W3, UCHII-W1 and UCHII-W3. The overall average of the derived relative proper motion is 85 km s${}^{-1}$. This mean proper motion is in agreement with the previous results from VLA multi-epoch observations. Our position and velocity variance and co-variance matrix analyses of the maser proper motions show its major axis to have a position angle of $-$79.4${}^{\circ }$, cutting through the dust cavity around MM1B and aligned in the northwest-southeast direction. We interpret this as the axis of the jet driving the CM2 shock and the maser motion. The complicated proper motions in MM1-W1 can be explained by the combined influence of the MM1 northeast-southwest bipolar outflow, CS(6-5) north-south collimated bipolar outflow, and the radio jet. The relative proper motions of the H${}_2$O masers in UCHII-W1 are likely not driven by the jets of MM1B protostar but by MM3-UCHII. Overall, the post-accretion burst relative proper motions of the H${}_2$O masers trace shocks of jet motion.

18 pages, 6 figures, accepted for publication by The Astrophysical Journal

References in corpus (12)

• An extraordinary outburst in the massive protostellar system NGC6334I-MM1: quadrupling of the millimeter continuum
• Trigonometric parallaxes of star forming regions in the Sagittarius spiral arm
• On the existence of accretion-driven bursts in massive star formation
• {Millimeter Multiplicity in NGC 6334 I and I(N)
• A heat-wave of accretion energy traced by masers in the G358-MM1 high-mass protostar
• Chemical tracers of episodic accretion in low-mass protostars
• The Massive Protostellar Cluster NGC6334I at 220 AU Resolution: Discovery of Further Multiplicity, Diversity and a Hot Multi-Core
• Detection of new methanol maser transitions associated with G358.93-0.03
• Discovery of six new class II methanol maser transitions, including the unambiguous detection of three torsionally excited lines toward G358.931-0.030
• A New Hardware Correlator in Korea: Performance Evaluation using KVN observations
• The high velocity outflow in NGC6334I
• A very young, compact bipolar H${}_2$O maser outflow in the intermediate-mass star-forming LkH$\alpha$ 234 region

Cited by in corpus (4)

• Multi-frequency VLBI observations of maser lines during the 6.7~GHz maser flare in the high-mass young stellar object G24.33$+$0.14}
• Overview of the Observing System and Initial Scientific Accomplishments of the East Asian VLBI Network (EAVN)
• The evolution of the H2O maser emission in the accretion burst source G358.93-0.03
• Identifying the Mechanisms of Water Maser Variability During the Accretion Burst in NGC6334I