Infall and outflow within 400 AU from a high-mass protostar

Goddi, C.; Moscadelli, L.; Sanna, A.

doi:10.1051/0004-6361/201117854

Cited by 84 publications

(110 citation statements)

References 20 publications

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“…6). The event characteristics are similar to those reported in Cep A ) but the signal-tonoise ratio in the spectra is less than 6 and it is not clear whether the velocity drift is caused by variability of a close pair of spectrally blended features or by motion of the gas (Goddi et al 2011). …”

Section: G22357+0066supporting

confidence: 69%

Discovery of four periodic methanol masers and updated light curve for a further one

Szymczak

Wolak

Bartkiewicz

2015

Monthly Notices of the Royal Astronomical Society

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We report the discovery of 6.7 GHz methanol maser periodic flares in four massive star forming regions and the updated light curve for the known periodic source G22.357+0.066. The observations were carried out with the Torun 32 m radio telescope between June 2009 and April 2014. Flux density variations with period of 120 to 245 d were detected for some or all spectral features. A variability pattern with a fast rise and relatively slow fall on time-scale of 30−60 d dominated. A reverse pattern was observed for some features of G22.357+0.066, while sinusoidal-like variations were detected in G25.411+0.105. A weak burst lasting ∼520 d with the velocity drift of 0.24 km s −1 yr −1 occurred in G22.357+0.066. For three sources for which high resolution maps are available, we found that the features with periodic behaviour are separated by more than 500 au from those without any periodicity. This suggests that the maser flares are not triggered by large-scale homogeneous variations in either the background seed photon flux or the luminosity of the exciting source and a mechanism which is able to produce local changes in the pumping conditions is required.

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Section: G22357+0066supporting

confidence: 69%

Discovery of four periodic methanol masers and updated light curve for a further one

Szymczak

Wolak

Bartkiewicz

2015

Monthly Notices of the Royal Astronomical Society

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“…a few hundred au. This is a typical order of separation seen between the shock fronts of young YSO jets and their driving sources (Goddi et al 2011;Torrelles et al 2011), and we could thus expect that the arc shape of the masers was formed in a bowshock tracing the front of a protostellar jet (Furuya et al 2000; Burns et al 2016). On the other hand, in the case that the North group masers are much closer to the ALLWISE object then the maser morphology would be better explained as an expanding ring (Moscadelli et al 2006;Trinidad et al 2009) for low-mass YSO and (Chibueze et al 2016;Torrelles et al 2011) for high-mass YSOs, with the driving source located near the center of the maser map; (0,0).…”

Section: Identifying the Driving Sourcementioning

confidence: 95%

“…In the case of a protostellar jet, the physical properties of the jet relates to the properties of the driving source. Thus, the 3D motions of masers can be used as a diagnostic to infer the properties of the YSO (Goddi et al 2011). The momentum rate of an outflow is given by P = 1.5×10 −3 V 2 10 R 2 100 ( Ω 4π )n g M yr −1 km s −1 (Goddi et al 2011).…”

Section: Investigating the Driving Source With Maser Kinematicsmentioning

confidence: 99%

“…Thus, the 3D motions of masers can be used as a diagnostic to infer the properties of the YSO (Goddi et al 2011). The momentum rate of an outflow is given by P = 1.5×10 −3 V 2 10 R 2 100 ( Ω 4π )n g M yr −1 km s −1 (Goddi et al 2011). Where V 10 is the maser velocity in units of 10 km s −1 , R 100 is the outflow length (given by the separation between the maser emission and the driving source) in units of 10 au, Ω is the jet opening angle, and n 8 is the ambient density in units of 10 8 cm −3 for which we consider a range of 10 7 to 10 9 cm −3 (Hollenbach et al 2013).…”

Section: Investigating the Driving Source With Maser Kinematicsmentioning

confidence: 99%

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Bow shocks in a newly discovered maser source in IRAS 20231+3440

Ogbodo

Burns

Handa

et al. 2017

Monthly Notices of the Royal Astronomical Society

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From measuring the annual parallax of water masers over one and a half years with VERA, we present the trigonometric parallax and corresponding distance of another newly identified water maser source in the region of IRAS 20231+3440 as π = 0.611 ± 0.022 mas and D = 1.64 ± 0.06 kpc respectively. We measured the absolute proper motions of all the newly detected maser spots (30 spots) and presented two pictures describing the possible spatial distribution of the water maser as the morphology marks out an arc of masers whose average proper motion velocity in the jet direction was 14.26 km s −1 . As revealed by the ALLWISE composite image, and by applying the colour-colour method of YSO identification and classification on photometric archived data, we identified the driving source of the north maser group to be a class I, young stellar object. To further probe the nature of the progenitor, we used the momentum rate maximum value (1.2×10 −4 M yr −1 km s −1 ) of the outflow to satisfy that the progenitor under investigation is a low mass young stellar object concurrently forming alongside an intermediate-mass YSO ∼ 60, 000 au (∼ 37 arcsecs) away from it.

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“…Since several years, we are conducting a campaign of multiepoch Very Long Baseline Interferometry (VLBI) observations of the strongest interstellar molecular masers (OH at 1.6 GHz, CH 3 OH at 6.7 GHz, and H 2 O at 22 GHz) toward a small sample of massive star-forming regions (Moscadelli et al 2007Sanna et al 2010a;Goddi et al 2011;Li et al 2012). Multi-epoch VLBI observations, achieving angular resolutions of 1-10 mas, permit to measure the proper motions of the maser emission centers, and, knowing the source distance and the maser V LSR (from Doppler effect), one can reconstruct the 3D kinematics of the masing gas.…”

Section: Introductionmentioning

confidence: 99%

A double-jet system in the G31.41 + 0.31 hot molecular core

Moscadelli

Cesaroni

et al. 2013

A&A

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Context. Many aspects of massive star ( > ∼ 10 M ) formation are still unclear. In particular, the outflow properties at close distance (100-1000 AU) from a massive young stellar object (MYSO) are not yet well established. Aims. This work presents a detailed study of the gas kinematics toward the hot molecular core (HMC) G31.41+0.31. Methods. To study the HMC 3D kinematics at milli-arcsecond angular resolution, we performed multi-epoch VLBI observations of the H 2 O 22 GHz and CH 3 OH 6.7 GHz masers, and single-epoch VLBI of the OH 1.6 GHz masers. Results. Water masers present a symmetric spatial distribution with respect to the HMC center, where two nearby (0. 2 apart), compact, VLA sources (labeled "A" and "B") are previously detected. The spatial distribution of a first group of water masers, named "J1", is well fit with an elliptical profile, and the maser proper motions mainly diverge from the ellipse center, with average speed of 36 km s −1 . These findings strongly suggest that the "J1" water maser group traces the heads of a young (dynamical time of 1.3 × 10 3 yr), powerful (momentum rate of 0.2 M yr −1 km s −1 ), collimated (semi-opening angle 10 • ) jet emerging from a MYSO located close (within ≈0. 15) to the VLA source "B". Most of the water features not belonging to "J1" present an elongated (≈2 in size), NE-SW oriented (PA ≈ 70 • ), S-shape distribution, which we denote with the label "J2". The elongated distribution of the "J2" group and the direction of motion, approximately parallel to the direction of elongation, of most "J2" water masers suggests the presence of another collimated outflow, emitted from a MYSO placed near the VLA source "A". The proper motions of the CH 3 OH 6.7 GHz masers, mostly diverging from the HMC center, also witness the expansion of the HMC gas driven by the "J1" and "J2" jets. The orientation (PA ≈ 70 • ) of the "J2" jet agrees well with that (PA = 68 • ) of the well-defined V LSR gradient across the HMC revealed by previous interferometric, thermal line observations. Furthermore, the "J2" jet is powerful enough to sustain the large momentum rate, 0.3 M yr −1 km s −1 , estimated from the interferometric, molecular line data in the assumption that the V LSR gradient represents a collimated outflow. These two facts lead us to favor the interpretation of the V LSR gradient across the G31.41+0.31 HMC in terms of a compact and collimated outflow.

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Infall and outflow within 400 AU from a high-mass protostar

Cited by 84 publications

References 20 publications

Discovery of four periodic methanol masers and updated light curve for a further one

Discovery of four periodic methanol masers and updated light curve for a further one

Bow shocks in a newly discovered maser source in IRAS 20231+3440

A double-jet system in the G31.41 + 0.31 hot molecular core

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