Methanol masers reveal the magnetic field of the high-mass protostar IRAS 18089-1732

Context. The importance of the magnetic field in high-mass-star formation is not yet fully clear and there are still many open questions concerning its role in the accretion processes and generation of jets and outflows. In the past few years, masers have been successfully used to probe the magnetic field morphology and strength at scales of a few au around massive protostars, by measuring linear polarisation angles and Zeeman splitting. The massive protostar IRAS 18089-1732 is a well studied high-mass-star forming region, showing a hot core chemistry and a disc-outflow system. Previous SMA observations of polarised dust revealed an ordered magnetic field oriented around the disc of IRAS 18089-1732. Aims. We want to determine the magnetic field in the dense region probed by 6.7 GHz methanol maser observations and compare it with observations in dust continuum polarisation, to investigate how the magnetic field in the compact maser region relates to the large-scale field around massive protostars. Methods. We reduced MERLIN observations at 6.7 GHz of IRAS 18089-1732 and we analysed the polarised emission by methanol masers. Results. Our MERLIN observations show that the magnetic field in the 6.7 GHz methanol maser region is consistent with the magnetic field constrained by the SMA dust polarisation observations. A tentative detection of circularly polarised line emission is also presented. Conclusions. We found that the magnetic field in the maser region has the same orientation as in the disk. Thus the large-scale field component, even at the au scale of the masers, dominates over any small-scale field fluctuations. We obtained, from the circular polarisation tentative detection, a field strength along the line of sight of 5.5 mG which appeared to be consistent with the previous estimates.Comment: 12 pages, 7 figures, accepted for publication in A&

Scientific, institutional and personal rivalries among Soviet geographers in the late Stalin era

Scientific, institutional and personal rivalries between three key centres of geographical research and scholarship (the Academy of Sciences Institute of Geography and the Faculties of Geography at Moscow and Leningrad State Universities) are surveyed for the period from 1945 to the early 1950s. It is argued that the debates and rivalries between members of the three institutions appear to have been motivated by a variety of scientific, ideological, institutional and personal factors, but that genuine scientific disagreements were at least as important as political and ideological factors in influencing the course of the debates and in determining their final outcome

Current Status of the EU-VGOS Project

The EU-VGOS project began in 2018 with\ua0the aim of using the VGOS infrastructure in Europe\ua0to investigate methods for VGOS data processing. The\ua0project is now structured into Working Groups dealing\ua0with operations (stations), e-transfer, correlation and\ua0post-processing, and analysis. This is a report on the\ua0status of the project

Varenius e o conhecimento matemático do século XVII Varenius and the mathematical knowledge in the seventeenth century

Neste artigo, discutimos o contexto do desenvolvimento da Geografia que, no século XVII, liberou-se do seu papel nas diferentes fés cristãs, bem como a importância da cisão dos Protestantes, em Luteranos e Calvinistas, para o processo de secularização, e o conseguinte estabelecimento da Geografia como ciência moderna. Analisamos a contribuição fundamental do luterano Bernhard Varen, cuja obra Geografia Geral apresenta o paradigma dessa nova ciência. Naquela época, a Geografia era considerada um ramo da matemática, e esta obra nos dá indícios sobre notações e conceitos matemáticos utilizados naquele século. Analisamos, particularmente, o uso da notação decimal de números não inteiros e algumas aplicações de conceitos trigonométricos, comparando a edição original com as principais reedições desta obra.<br>In this paper, we discuss the context for the development of geography from the seventeenth century when it became liberated from its function in the service of the different Christian faiths; we discuss the importance of the division of the Protestant confession into the Lutheran and the Reformed one for the process of secularization and for the establishment of geography as a modern science. We analyse the fundamental contribution by the Lutheran Bernhard Varen whose volume General Geography constitutes the paradigm for this new science. At that time, Geography was considered to be a branch of mathematics, and this book offers us insights into both, mathematical notations and mathematical procedures. We analyse, in particular, the use of the decimal number notation for nonintegral numbers and also some applications of trigonometry, comparing the original edition with the major re-editions of this seminal work

Methanol masers and magnetic field in IRAS18089-1732

Theoretical simulations have shown that magnetic fields play an important role in massive star formation: they can suppress fragmentation in the star forming cloud, enhance accretion via disc and regulate outflows and jets. However, models require specific magnetic configurations and need more observational constraints to properly test the impact of magnetic fields. We investigate the magnetic field structure of the massive protostar IRAS18089-1732, analysing 6.7 GHz CH3OH maser MERLIN observations. IRAS18089-1732 is a well studied high mass protostar, showing a hot core chemistry, an accretion disc and a bipolar outflow. An ordered magnetic field oriented around its disc has been detected from previous observations of polarised dust. This gives us the chance to investigate how the magnetic field at the small scale probed by masers relates to the large scale field probed by the dust