J/ApJ/908/175 NGC6334I-MM1 system watermasers spatiokinematics (Chibueze+, 2021)
The Extraordinary Outburst in the Massive Protostellar System NGC 6334 I-MM1:
Spatiokinematics of Water Masers during a Contemporaneous Flare Event.
Chibueze J.O., MacLeod G.C., Vorster J.M., Hirota T., Brogan C.L.,
Hunter T.R., van Rooyen R.
<Astrophys. J., 908, 175 (2021)>
=2021ApJ...908..175C 2021ApJ...908..175C
ADC_Keywords: Stars, flare; Star Forming Region; Spectra, radio; Masers;
Proper motions
Keywords: Stellar jets ; Star forming regions ; Astrophysical masers ;
Long baseline interferometry ; Shocks
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 H2O maser proper motions were detected in five
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 85km/s. This mean proper motion is in agreement with
the previous results from VLA multiepoch observations. Our position as
well as the velocity variance and covariance matrix analyses of the
maser proper motions show its major axis to have a position angle of
-79.4, cutting through the dust cavity around MM1B and being 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, the CS(6-5) north-south
collimated bipolar outflow, and the radio jet. The relative proper
motions of the H2O masers in UCHII-W1 are likely not driven by the
jets of the MM1B protostar but by MM3-UCHII. Overall, the
post-accretion burst relative proper motions of the H2O masers trace
shocks of jet motion.
Description:
The ongoing 22.2GHz (1.3cm) water maser observations reported here
were made using the 26m telescope of Hartebeesthoek Radio Astronomy
Observatory (HartRAO). The single-dish results reported in this paper
cover observations taken between 2013 May 7 and 2020 December 2.
H2O masers in NGC 6334I were observed with the KVN and VERA Array
(KaVA) in three epochs taken on 2015 November 21 (2015.89), 2015
December 15 (2015.95), and 2016 January 4 (2016.01), respectively.
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------
17 20 53.35 -35 47 01.4 NGC 6334I = MFSW I
---------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 68 186 Parameters of the H2O Maser Proper Motions
--------------------------------------------------------------------------------
See also:
J/A+A/316/102 : JHK Photometry in NGC 6334 (Tapia+, 1996)
J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)
J/ApJ/832/187 : ALMA and VLA radio continuum obs. of NGC 6334I (Brogan+, 2016)
J/ApJ/866/87 : VLA 22GHz water masers obs. in NGC6334I-MM1 (Brogan+, 2018)
J/ApJ/854/170 : Methanol (CH3OH) and OH masers in NGC 6334I (Hunter+, 2018)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Maser feature ID
5- 12 A8 --- Reg Region
14- 19 F6.3 arcsec dRA [-0.7/0.2] Offset, in Right Ascension (1)
21- 26 F6.3 arcsec dDE [-0.07/6] Offset, in Declination (1)
28- 34 F7.3 mas/yr pmX [-12/9.95]? Proper motion in X direction
36- 40 F5.3 mas/yr e_pmX [0.1/3]? Uncertainty in pmX
42- 48 F7.3 mas/yr pmY [-16.6/38.4]? Proper motion in Y direction
50- 54 F5.3 mas/yr e_pmY [0.1/4]? Uncertainty in pmY
56- 62 F7.3 km/s VLSR [-64.1/0.64] Velocity, relative to LSR
64- 64 I1 --- Epoch1 [0,1] Detection in Epoch1
66- 66 I1 --- Epoch2 [0,1] Detection in Epoch2
68- 68 I1 --- Epoch3 [0,1] Detection in Epoch3
--------------------------------------------------------------------------------
Note (1): Offsets are with respect to the KaVA reference maser spot at
(RA,DE) = (17:20:52.600, -35:46:50.508, ICRS)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 23-Feb-2024