J/MNRAS/430/1309 H2O masers in AFGL 2591 VLA 3-N (Trinidad+, 2013)
Formation and evolution of the water maser outflow event in AFGL 2591 VLA 3-N.
Trinidad M.A., Curiel S., Estalella R., Canto J., Raga A., Torrelles J.M.,
Patel N.A., Gomez J.F., Anglada G., Carrasco-Gonzalez C., Rodriguez L.F.
<Mon. Not. R. Astron. Soc., 430, 1309-1323 (2013)>
=2013MNRAS.430.1309T 2013MNRAS.430.1309T
ADC_Keywords: YSOs ; Masers ; Radio sources
Keywords: masers; stars: formation - ISM: individual objects: AFGL 2591 -
ISM: jets and outflows
Abstract:
In this paper we analyse multi-epoch very long baseline interferometry
water maser observations carried out with the Very Long Baseline Array
towards the high-mass star-forming region AFGL 2591. We detected maser
emission associated with the radio continuum sources VLA 2 and VLA 3.
In addition, a water maser cluster, VLA 3-N, was detected ∼0.5arcsec
north of VLA 3. We concentrate the discussion of this paper on the
spatio-kinematical distribution of the water masers towards VLA 3-N.
The water maser emission towards the region VLA 3-N shows two
bow-shock-like structures, northern and southern, separated from each
other by ∼100mas (∼330AU). The spatial distribution and kinematics
of the water masers in this cluster have persisted over a time span of
7yr. The northern bow shock has a somewhat irregular morphology, while
the southern one has a remarkably smooth morphology. We measured the
proper motions of 33 water maser features, which have an average
proper motion velocity of ∼1.3mas/yr (∼20km/s). The morphology and
the proper motions of this cluster of water masers show systematic
expanding motions that could imply one or two different centres of
star formation activity. We made a detailed model for the southern
structure, proposing two different kinematic models to explain the
three-dimensional spatio-kinematical distribution of the water masers:
(1) a static central source driving the two bow-shock structures and
(2) two independent driving sources, one of them exciting the northern
bow-shock structure, and the other one, a young runaway star moving in
the local molecular medium exciting and moulding the remarkably
smoother southern bow-shock structure. Future observations will be
necessary to discriminate between the two scenarios, in particular by
identifying the still unseen driving source(s).
Description:
Multi-epoch water maser observations were carried out with the Very
Long Baseline Array (VLBA) of the National Radio Astronomy Observatory
(NRAO) towards AFGL 2591 at three epochs (2001 December 2, 2002
February 11 and 2002 March 5). We observed the 616-523 water maser
transition (rest frequency = 22235.08MHz) with a bandwidth of 8MHz
sampled over 512 channels (spectral resolution 15.625kHz=0.21km/s) and
centred at VLSR=-7.6km/s. All 10 VLBA stations of the array were
available and recorded data during an observing time of 6h per
epoch. The data were correlated at the NRAO Array Operations Center.
Objects:
-------------------------------------------
RA (2000) DE Designation(s)
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20 29 24.88 +40 11 19.9 AFGL 2591 VLA 3-N
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 28 613 Parameters of the water maser spots detected
in AFGL 2591 VLA 3-N
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See also:
J/A+A/475/549 : AFGL 2591 maps in CS, SO and HCN lines (Benz+, 2007)
J/A+A/551/A43 : AFGL 2591 multi-wavelength maps (Johnston+, 2013)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1 I1 --- Epoch [1/3] Observed VLBA 2001-2002 epoch (1)
3- 8 F6.2 mas oRA Offset in right ascension (2)
10- 15 F6.2 mas oDE Offset in declination (2)
17- 22 F6.2 km/s Vlsr LSR velocity
24- 28 F5.2 Jy Int Intensity (in Jy/beam)
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Note (1): Epochs as follows:
1 = 2001-Dec-02
2 = 2002-Feb-11
3 = 2002-Mar-05
Note (2): The (0,0) position corresponds to coordinates
20:29:24.879+40:11:19.47 (J2000, ±0.01").
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 16-Apr-2014