Evidence supporting the kinematic interpretation of water maser proper motions

Goddi, C.; Moscadelli, L.; Torrelles, J. M.; Uscanga, L.; Cesaroni, R.

doi:10.1051/0004-6361:200500230

Cited by 41 publications

(59 citation statements)

References 20 publications

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“…3; see also Goddi et al 2006); and 2) assumption of uniform motions (e.g., Reid et al 1988;Gwinn et al 1992). The tolerance in the change of peak LSR velocity for persistent features was fixed to less than their spectral FWHM (see Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Change in physical and/or excitation conditions of maser-emitting gas can in principle lead to apparent motions (Christmas-tree effect). Concerning 22.2 GHz H 2 O masers, accurate proper motion measurements towards several HMSFRs strongly suggest that this maser emission traces physical motions of gas bullets, powered by stellar winds or jets emitted from massive YSO(s) (e.g., Goddi et al 2006). Since our study is one of the first attempts to use proper motions of 6.7 GHz methanol masers to infer gas kinematics in HMSFRs, we propose a few arguments supporting the kinematic interpretation of features' proper motions.…”

Section: Interpretation Of 67 Ghz Maser Proper Motionsmentioning

confidence: 96%

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VLBI study of maser kinematics in high-mass star-forming regions

Sanna

Moscadelli

Cesaroni

et al. 2010

A&A

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Aims. To study the high-mass star-forming process, we started a large project to unveil the gas kinematics close to young stellar objects (YSOs) through the Very Long Baseline Interferometry (VLBI) of maser associations. By comparing the high spatial resolution maser data that traces the inner kinematics of the (proto)stellar cocoon with interferometric thermal data that traces the large-scale environment of the hot molecular core (HMC) harboring the (proto)stars, we can investigate the nature and identify the sources of large-scale motions. The present paper focuses on the high-mass star-forming region G16.59-0.05. Methods. Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G16.59-0.05: H 2 O at 22.2 GHz (4 epochs), CH 3 OH at 6.7 GHz (3 epochs), and OH at 1.665 GHz (1 epoch). In addition, we performed high-resolution (≥0. 1), high-sensitivity (<0.1 mJy) VLA observations of the radio continuum emission from the starforming region at 1.3 and 3.6 cm.Results. This is the first work to report accurate measurements of the relative proper motions of the 6.7 GHz CH 3 OH masers. The different spatial and 3-D velocity distributions clearly indicate that the 22 GHz water and 6.7 GHz methanol masers trace different kinematic environments. The bipolar distribution of 6.7 GHz maser line-of-sight velocities and the regular pattern of observed proper motions suggest that these masers are tracing rotation around a central mass of about 35 M . The flattened spatial distribution of the 6.7 GHz masers, oriented NW−SE, suggests that they can originate in a disk/toroid rotating around the massive YSO that drives the 12 CO (2−1) outflow, oriented NE−SW, observed on an arcsec scale. The extended, radio continuum source observed close to the 6.7 GHz masers could be excited by a wide-angle wind emitted from the YSO associated with the methanol masers, and such a wind has proven to be energetic enough to drive the NE−SW 12 CO (2−1) outflow. The H 2 O masers are distributed across a region offset about 0. 5 to the NW of the CH 3 OH masers, in the same area as where the emission of high-density molecular tracers, typical of HMCs, was detected. We postulate that a distinct YSO, possibly in an earlier evolutionary phase than what excites the methanol masers, is responsible for the excitation of the water masers and the HMC molecular lines.

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Section: Discussionmentioning

confidence: 99%

Section: Interpretation Of 67 Ghz Maser Proper Motionsmentioning

confidence: 96%

VLBI study of maser kinematics in high-mass star-forming regions

Sanna

Moscadelli

Cesaroni

et al. 2010

A&A

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“…If the protostellar wind directly impacts on the cavity wall, this could drive a J-type shock into the cavity wall, a mechanism which has been proposed for masers in highmass protostars (Goddi et al 2006). Another possibility is that the masers originate in the jet itself, or at least that they are connected to the jet (Furuya et al 2003), which is almost certainly true for the high-velocity masers ( > 20 km s −1 ).…”

Section: Outflow Componentsmentioning

confidence: 99%

Water in star-forming regions withHerschel(WISH)

Kristensen

Dishoeck

Bergin

et al. 2012

A&A

250

589

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Context. Water is a key tracer of dynamics and chemistry in low-mass star-forming regions, but spectrally resolved observations have so far been limited in sensitivity and angular resolution, and only data from the brightest low-mass protostars have been published. Aims. The first systematic survey of spectrally resolved water emission in 29 low-mass (L < 40 L ) protostellar objects is presented. The sources cover a range of luminosities and evolutionary states. The aim is to characterise the line profiles to distinguish physical components in the beam and examine how water emission changes with protostellar evolution. Methods. H 2 O was observed in the ground-state 1 10 -1 01 transition at 557 GHz (E up /k B ∼ 60 K) as single-point observations with the Heterodyne Instrument for the Far-Infrared (HIFI) on Herschel in 29 deeply embedded Class 0 and I low-mass protostars. Complementary far-IR and sub-mm continuum data (including PACS data from our programme) are used to constrain the spectral energy distribution (SED) of each source. H 2 O intensities are compared to inferred envelope properties, e.g., mass and density, outflow properties and CO 3-2 emission. Results. H 2 O emission is detected in all objects except one (TMC1A). The line profiles are complex and consist of several kinematic components tracing different physical regions in each system. In particular, the profiles are typically dominated by a broad Gaussian emission feature, indicating that the bulk of the water emission arises in outflows, not in the quiescent envelope. Several sources show multiple shock components appearing in either emission or absorption, thus constraining the internal geometry of the system. Furthermore, the components include inverse P-Cygni profiles in seven sources (six Class 0, one Class I) indicative of infalling envelopes, and regular P-Cygni profiles in four sources (three Class I, one Class 0) indicative of expanding envelopes. Molecular "bullets" moving at > ∼ 50 km s −1 with respect to the source are detected in four Class 0 sources; three of these sources were not known to harbour bullets previously. In the outflow, the H 2 O/CO abundance ratio as a function of velocity is nearly the same for all line wings, increasing from 10 −3 at low velocities (<5 km s −1 ) to > ∼ 10 −1 at high velocities (>10 km s −1 ). The water abundance in the outer cold envelope is low, > ∼ 10 −10 . The different H 2 O profile components show a clear evolutionary trend: in the younger Class 0 sources the emission is dominated by outflow components originating inside an infalling envelope. When large-scale infall diminishes during the Class I phase, the outflow weakens and H 2 O emission all but disappears.

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“…In the case of BRC 37 and BRC 39, the alignment between the maser position and the HH objects provides further evidence on the relation between maser emission and collimated jets (e.g., Imai et al 2006;Goddi et al 2006).…”

Section: Discussionmentioning

confidence: 79%

High‐Resolution H₂O Maser Observations towardIRASSources in Bright‐Rimmed Clouds

Valdettaro

Migenes

Trinidad

et al. 2008

ApJ

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Bright-rimmed clouds (BRCs) are clouds that have been compressed by an external ionization shock front. We present the first high-resolution VLA observations of 20 of these BRCs in the northern hemisphere. We detected water maser emission from three objects: IRAS 21346+5714 (BRC 36), IRAS 21388+5622 (BRC 37), and IRAS 21445+5712 (BRC 39). The low detection rate supports the evidence that BRCs produce mostly low-luminosity objects, for which maser emission is weak and episodic, and suggests that the embedded sources are in a more advanced evolutionary phase than Class 0 objects.

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Evidence supporting the kinematic interpretation of water maser proper motions

Cited by 41 publications

References 20 publications

VLBI study of maser kinematics in high-mass star-forming regions

VLBI study of maser kinematics in high-mass star-forming regions

Water in star-forming regions withHerschel(WISH)

High‐Resolution H₂O Maser Observations towardIRASSources in Bright‐Rimmed Clouds

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Evidence supporting the kinematic interpretation of water maser proper motions

Cited by 41 publications

References 20 publications

VLBI study of maser kinematics in high-mass star-forming regions

VLBI study of maser kinematics in high-mass star-forming regions

Water in star-forming regions withHerschel(WISH)

High‐Resolution H2O Maser Observations towardIRASSources in Bright‐Rimmed Clouds

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Product

Resources

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High‐Resolution H₂O Maser Observations towardIRASSources in Bright‐Rimmed Clouds