Methanol masers probing the ordered magnetic field of W75N

Surcis, G.; Vlemmings, Wouter; Dodson, Richard; Langevelde, H. J. van

doi:10.1051/0004-6361/200912790

Cited by 46 publications

(97 citation statements)

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“…Considering a reasonable value for α Z in the range 0.005 km s −1 G −1 < α Z < 0.05 km s −1 G −1 (Surcis et al 2011b), we have a range of β between 10 −4 and 10 −2 for both sources. As it was found for all the previous massive star-forming regions investigated using the 6.7-GHz CH 3 OH maser emission (Surcis et al 2009(Surcis et al , 2011b(Surcis et al , 2012, magnetic fields play an important role in the dynamics of IRAS 06058+2138-NIRS1 and S255-IR.…”

Section: The Importance Of Magnetic Fields In High-mass Star Formationsupporting

confidence: 57%

“…the linear polarization vectors we take into account the errors associated with θ, which we indicate here as ε − and ε + , i.e. Because of technical limitations, the spectral resolution of the past observations was of about 0.1 km s −1 , and we were only able to measure the Zeeman-splitting (ΔV Z ) from the crosscorrelation between RR and LL spectra of the CH 3 OH maser features (Surcis et al 2009(Surcis et al , 2011b(Surcis et al , 2012. Nowadays, although using the same observing setup, the EVN SFXC at JIVE enables us to correlate the spectral data with a larger number of channels than previously possible on the JIVE hardware correlator (Schilizzi et al 2001), providing a better spectral resolution (i.e., ∼0.05 km s −1 ).…”

Section: Discussionmentioning

confidence: 99%

“…Because the massive star-forming regions investigated so far are at a distance of a few kpc, Φ f is estimated to be within the errors of the linear polarization angles of the CH 3 OH maser emission (Surcis et al 2009(Surcis et al , 2011b(Surcis et al , 2012. This The red full line is the limit of emerging brightness temperature above which the CH 3 OH masers are considered saturated (T b ΔΩ > 2.6 × 10 9 K sr; Surcis et al 2011a), and the dotted line gives the lower limit to the linear polarization fraction for saturated masers (P l ≈ 4.5%, Surcis et al 2012).…”

Section: Magnetic Field Orientationsmentioning

confidence: 96%

“…Over the last years, the high importance of using masers as probes of magnetic fields on the smallest scales (10-100 AU) has been proven (e.g., Vlemmings et al 2006Vlemmings et al , 2010Surcis et al 2011aSurcis et al , 2011bSurcis et al , 2012. In particular, the 6.7-GHz CH 3 OH masers, which are among the most abundant maser species in massive star-forming regions, are playing a crucial role in determining the magnetic field morphology (e.g., Surcis et al 2009Surcis et al , 2011bSurcis et al , 2012. Magnetic fields have mainly been detected along outflows and in a few cases on surfaces of disk/tori (Vlemmings et al 2010;Surcis et al 2009Surcis et al , 2011bSurcis et al , 2012.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the 6.7-GHz CH 3 OH masers, which are among the most abundant maser species in massive star-forming regions, are playing a crucial role in determining the magnetic field morphology (e.g., Surcis et al 2009Surcis et al , 2011bSurcis et al , 2012. Magnetic fields have mainly been detected along outflows and in a few cases on surfaces of disk/tori (Vlemmings et al 2010;Surcis et al 2009Surcis et al , 2011bSurcis et al , 2012. Moreover, 6.7-GHz CH 3 OH masers are also ideal for measuring the Zeeman-splitting even though the exact proportionality between the measured splitting and the magnetic field strength is still uncertain (Vlemmings et al 2011).…”

Section: Introductionmentioning

confidence: 99%

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EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions

Surcis

Vlemmings

Langevelde

et al. 2013

A&A

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Context. Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The simulations show that magnetic fields play an important role in the formation and dynamics of molecular outflows. Masers, in particular 6.7-GHz CH 3 OH masers, are the best probes of the magnetic field morphologies around massive young stellar objects on the smallest scales of 10-100 AU. Aims. Providing new observational measurements of the morphology of magnetic fields around massive young stellar objects by using 6.7-GHz CH 3 OH maser emission is very important for setting constraints on the numerical simulations of massive star formation. Methods. This paper focuses on 4 massive young stellar objects, IRAS 06058+2138-NIRS 1, IRAS 22272+6358A, S255-IR, and S231, which complement our previous 2012 sample (the first EVN group). From all these sources, molecular outflows have been detected in the past. Seven of the European VLBI Network antennas were used to measure the linear polarization and Zeeman-splitting of the 6.7-GHz CH 3 OH masers in the star-forming regions in this second EVN group. Results. We detected a total of 128 CH 3 OH masing cloudlets. Fractional linear polarization (0.8%-11.3%) was detected towards 18% of the CH 3 OH masers in our sample. The linear polarization vectors are well ordered in all the massive young stellar objects. We measured significant Zeeman-splitting in IRAS 06058+2138-NIRS 1 (ΔV Z = 3.8 ± 0.6 m s −1 ) and S255-IR (ΔV Z = 3.2 ± 0.7 m s −1 ). Conclusions. By considering the 20 massive young stellar objects towards which the morphology of magnetic fields was determined by observing 6.7-GHz CH 3 OH masers in both hemispheres, we find no evident correlation between the linear distributions of CH 3 OH masers and the outflows or the linear polarization vectors. On the other hand, we present first statistical evidence that the magnetic field (on scales 10-100 AU) is primarily oriented along the large-scale outflow direction. Moreover, we empirically find that the linear polarization fraction of unsaturated CH 3 OH masers is P l < 4.5%.

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Section: The Importance Of Magnetic Fields In High-mass Star Formationsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: Magnetic Field Orientationsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions

Surcis

Vlemmings

Langevelde

et al. 2013

A&A

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Magnetic Fields with the Atacama Large Millimeter/Submillimeter Array

Vlemmings

2014

Astrophysics and Space Science Library

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The Atacama Large Millimeter/submillimeter Array (ALMA) is one of the largest radio telescopes and is located at 5;000 m altitude in the Atacama desert in Chile. Its unprecedented sensitivity at extremely high angular and spectral resolution in the (sub-)millimetre wavelength regime, allows for countless advances in astrophysics. One of the areas in which ALMA can make unique contributions, is in that of the study of astrophysical magnetic fields. ALMA is expected to map the magnetic field geometry, and in some cases strength, in a large number of star forming regions, around evolved stars and planetary nebulae, and in nearby galaxies. This chapter provides examples of the amount of improvement ALMA offers the study of magnetic fields based on the current state-of-the-art and shortly introduces new tools that will be available to analyse (sub-)millimetre polarimetric observations. The Atacama Large Millimeter/Submillimeter ArrayThe Atacama Large Millimeter/submillimeter Array (ALMA) is a large international (sub-)millimeter-wavelength radio telescope array in the Atacama Desert of northern Chile. It consists of a total of 66 antennas operating in the wavelength range from 0:4 to 4 mm. Because of its unmatched sensitivity at very high spectral and spatial resolution, ALMA provides new insights into many astrophysical topics, from the formation of stars and planets to the evolution of the most distant galaxies. As ALMA is able to observe in full polarization mode, it can also reveal the magnetic field with a sensitivity and resolution that has not previously been possible.ALMA is a partnership between Europe, North America (USA and Canada) and East Asia (Japan and Taiwan) in cooperation with the Republic of Chile. The ALMA project is coordinated by the Joint ALMA Office based in Santiago de Chile. The ALMA observatory is operated from the Operation Support Facility (OSF), which is situated at 2,900 m altitude. The array itself and the correlator are located at the W. Vlemmings ( )

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Radio jets from young stellar objects

Anglada

Rodrı́guez²,

Carrasco-González³

2018

Astron Astrophys Rev

132

151

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Jets and outflows are ubiquitous in the process of formation of stars since outflow is intimately associated with accretion. Free-free (thermal) radio continuum emission in the centimeter domain is associated with these jets. The emission is relatively weak and compact, and sensitive radio interferometers of high angular resolution are required to detect and study it. One of the key problems in the study of outflows is to determine how they are accelerated and collimated. Observations in the cm range are most useful to trace the base of the ionized jets, close to the young central object and the inner parts of its accretion disk, where optical or near-IR imaging is made difficult by the high extinction present. Radio recombination lines in jets (in combination with proper motions) should provide their 3D kinematics at very small scale (near their origin). Future instruments such as the Square Kilometre Array (SKA) and the Next Generation Very Large Array (ngVLA) will be crucial to perform this kind of sensitive observations. Thermal jets are associated with both high and low mass protostars and possibly even with objects in the substellar domain. The ionizing mechanism of these radio jets appears to be related to shocks in the associated outflows, as suggested by the observed correlation between the centimeter luminosity and the outflow momentum rate. From this correlation and that of the centimeter luminosity with the bolometric luminosity of the system it will be possible to discriminate between unresolved HII regions and jets, and to infer additional physical properties of the embedded objects. Some jets associated with young stellar objects (YSOs) show indications of nonthermal emission (negative spectral indices) in part of their lobes. Linearly polarized synchrotron emission has been found in the jet of HH 80-81, allowing one to measure the direction and intensity of the jet magnetic field, a key ingredient to determine the collimation and ejection mechanisms. As only a fraction of the emission is polarized, very sensitive observations such as those that will be feasible with the interferometers previously mentioned are required to perform studies in a large sample of sources. Jets are present in many kinds of astrophysical scenarios. Characterizing radio jets in YSOs, where thermal emission allows one to determine their physical conditions in a reliable way, would also be useful in understanding acceleration and collimation mechanisms in all kinds of astrophysical jets, such as those associated with stellar and supermassive black holes and planetary nebulae.

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Methanol masers probing the ordered magnetic field of W75N

Cited by 46 publications

References 32 publications

EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions

EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions

Magnetic Fields with the Atacama Large Millimeter/Submillimeter Array

Radio jets from young stellar objects

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