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Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The simulations show that magnetic fields can play a crucial role not only in the formation and dynamics of molecular outflows, but…

Solar and Stellar Astrophysics · Physics 2015-03-10 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , A. Bartkiewicz , H. Engelkamp

Our goal is to measure and model the magnetic field distribution in the disk wind of the young stellar object (YSO) IRAS 21078+5211. We performed sensitive global Very Long Baseline Interferometry observations of the polarized emission of…

Solar and Stellar Astrophysics · Physics 2023-12-20 Luca Moscadelli , André Oliva , Gabriele Surcis , Alberto Sanna , Maria Teresa Beltrán , Rolf Kuiper

In Orion BN/KL, proper motions of 7 mm vibrationally-excited SiO masers trace rotation of a nearly edge-on disk and a bipolar wide-angle outflow 10-100 AU from radio Source I, a binary young stellar object (YSO) of ~20 Msun. Here we map…

Astrophysics of Galaxies · Physics 2015-06-16 L. J. Greenhill , C. Goddi , C. J. Chandler , L. D. Matthews , E. M. L. Humphreys

Aims: We want to study the physical properties of the ionized jet emission in the vicinity of an O-type young stellar object (YSO), and estimate how efficient is the transfer of energy and momentum from small- to large-scale outflows.…

Astrophysics of Galaxies · Physics 2016-12-07 A. Sanna , L. Moscadelli , R. Cesaroni , A. Caratti o Garatti , C. Goddi , C. Carrasco-González

Aims: In order to test the nature of an (accretion) disk in the vicinity of Cepheus A HW2, we measured the three-dimensional velocity field of the CH3OH maser spots, which are projected within 1000au of the HW2 object, with an accuracy of…

Astrophysics of Galaxies · Physics 2017-07-26 A. Sanna , L. Moscadelli , G. Surcis , H. J. van Langevelde , K. J. E. Torstensson , A. M. Sobolev

Aims: We have observed the 6030 and 6035 MHz transitions of OH in high-mass star-forming regions to obtain magnetic field estimates in both maser emission and absorption. Methods: Observations were taken with the Effelsberg 100 m telescope.…

Astrophysics · Physics 2009-11-11 Vincent L. Fish , Mark J. Reid , Karl M. Menten , Thushara Pillai

In an attempt to probe the magnetic field morphology near the massive young star Orion-IRc2, we mapped the linear polarization of its J=2-1 SiO masers, in both the v=0 and v=1 vibrational levels, with 0.5 arcsec resolution. The intense v=1…

Astrophysics · Physics 2009-11-10 R. L. Plambeck , M. C. H. Wright , R. Rao

We analyze observational data on methanol masers in the disks of young massive stellar objects in the massive star formation regions: NGC6334I, G33.641-0.228, G12.89+0.49. Special attention is paid to analysis of the magnetic fields and…

Solar and Stellar Astrophysics · Physics 2025-11-14 P. I. Pavlova , S. A. Khaibrakhmanov , A. M. Sobolev

Kinematic information is crucial for understanding the evolution of complex systems, such as interstellar gas. Obtaining full 3D kinematic information is a crucial final step for modeling and interpretation. Molecular clouds are nurseries…

Astrophysics of Galaxies · Physics 2025-09-24 Ji-Xuan Zhou , Guang-Xing Li , Bing-Qiu Chen

We present multi-epoch VLBA imaging of the 28SiO v=1 & v=2, J=1-0 maser emission toward the massive YSO Orion Source I. Both SiO transitions were observed simultaneously with an angular resolution of ~0.5 mas (~0.2 AU for d=414 pc). Here we…

Solar and Stellar Astrophysics · Physics 2014-11-20 L. D. Matthews , L. J. Greenhill , C. Goddi , C. J. Chandler , E. M. L. Humphreys , M. Kunz

We previously observed the star-forming region G16.59$-$0.05 through interferometric observations of both thermal and maser lines, and identified a high-mass young stellar object (YSO) which is surrounded by an accretion disk and drives a…

Solar and Stellar Astrophysics · Physics 2019-02-20 Luca Moscadelli , Alberto Sanna , Riccardo Cesaroni , Victor M. Rivilla , Ciriaco Goddi , Kazi L. J. Rygl

Magnetic fields are an important component of the interstellar medium (ISM) and exhibit strongly varying field strengths and a non-trivial correlation with the gas density. Its dynamical impact varies between individual regions of the ISM…

Astrophysics of Galaxies · Physics 2021-08-20 Philipp Girichidis

[Context] Recent detections of disks around young high-mass stars support the idea of massive star formation through accretion rather than coalescence, but the detailed kinematics in the equatorial region of the disk candidates is not well…

Astrophysics of Galaxies · Physics 2015-06-04 K. -S. Wang , F. F. S. van der Tak , M. R. Hogerheijde

We perform imaging and analyses of SMA 1.3 mm continuum, C18O (2-1) and 12CO (2-1) line data of 17 Class 0 and 0/I protostars to study their gas kinematics on a 1,000-AU scale. Continuum and C18O (2-1) emission are detected toward all the…

Solar and Stellar Astrophysics · Physics 2015-06-23 Hsi-Wei Yen , Patrick M. Koch , Shigehisa Takakuwa , Paul T. P. Ho , Nagayoshi Ohashi , Ya-Wen Tang

Context. Understanding the connection between outflows, winds, accretion and disks in the inner protostellar regions is crucial for comprehending star and planet formation process. Aims. We aim to we explore the inner 300 au of the…

We characterize the molecular environment of candidate massive young stellar objects (MYSOs) signposted by methanol masers. Single pixel observations of 10 transitions of HCO^+, CO and CS isotopomers were carried out, using the IRAM 30m…

Astrophysics · Physics 2009-11-13 M. Szymczak , A. Bartkiewicz , A. M. S. Richards

IRAS20126+4104 is a well studied B0.5 protostar that is surrounded by a ~1000 au Keplerian disk and is where a large-scale outflow originates. Both 6.7-GHz CH3OH masers and 22-GHz H2O masers have been detected toward this young stellar…

Solar and Stellar Astrophysics · Physics 2014-03-05 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , L. Moscadelli , B. Hutawarakorn Kramer

Massive young stellar objects (MYSO) are surrounded by massive dusty envelopes. Our aim is to establish their density structure on scales of ~1000 AU, i.e. a factor 10 increase in angular resolution compared to similar studies performed in…

Context. Maser emission is a strong tool for studying high mass star forming regions and their evolutionary stages. OH masers in particular can trace the circumstellar material around protostars and determine their magnetic field strengths…

Astrophysics of Galaxies · Physics 2017-12-13 K. A. Edris , G. A. Fuller , S. Etoka , R. J. Cohen

A fully three-dimensional computation of induction processes in a disk is performed to investigate the evolution of a large-scale magnetic field in gas-rich barred and spiral galaxies in the presence of field diffusion. As input parameters…

Astrophysics · Physics 2007-05-23 S. von Linden , K. Otmianowska-Mazur , H. Lesch , G. Skupniewicz
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