Results 31 to 40 of about 1,279 (175)
Turbulence in the interstellar medium [PDF]
, 2014 Turbulence is ubiquitous in the insterstellar medium and plays a major role in several processes such as the formation of dense structures and stars, the stability of molecular clouds, the amplification of magnetic fields, and the re-acceleration and ...
Chian, A. C. -L. +9 more
core +1 more source
The Discovery of the Zeeman Effect in 38 GHz Class II Methanol Masers
The Astrophysical Journal, 2023 Magnetic fields likely play an important role in star formation, but the number of directly measured magnetic field strengths remains scarce. We observed the 38.3 and 38.5 GHz Class II methanol (CH _3 OH) maser lines toward the high-mass star-forming ...
E. Momjian, A. P. Sarma
doaj +1 more source
The Astrophysical Journal Supplement Series, 2023 We have conducted a systematic line survey, primarily focused on transitions of the methanol and ammonia molecules, and monitoring observations of masers toward the high-mass star-forming region NGC 6334I.
Jiong-Heng Wu +12 more
doaj +1 more source
QCL‐based frequency metrology from the mid‐infrared to the THz range: a review
Nanophotonics, Volume 8, Issue 2, Page 181-204, June 2018., 2018 Abstract Quantum cascade lasers (QCLs) are becoming a key tool for plenty of applications, from the mid‐infrared (mid‐IR) to the THz range. Progress in related areas, such as the development of ultra‐low‐loss crystalline microresonators, optical frequency standards, and optical fiber networks for time and frequency dissemination, is paving the way for ...
Luigi Consolino +3 more
wiley +1 more source
Review of Zeeman Effect Observations of Regions of Star Formation
Frontiers in Astronomy and Space Sciences, 2019 The Zeeman effect is the only observational technique available to measure directly the strength of magnetic fields in regions of star formation. This chapter reviews the physics of the Zeeman effect and its practical use in both extended gas and in ...
Richard M. Crutcher, Athol J. Kemball
doaj +1 more source
Exact Relativistic Magnetized Haloes around Rotating Disks
Advances in Mathematical Physics, Volume 2015, Issue 1, 2015., 2015 The study of the dynamics of magnetic fields in galaxies is one of important problems in formation and evolution of galaxies. In this paper, we present the exact relativistic treatment of a rotating disk surrounded by a magnetized material halo. The features of the halo and disk are described by the distributional energy‐momentum tensor of a general ...
Antonio C. Gutiérrez-Piñeres +2 more
wiley +1 more source
AGN Obscuration and the Unified Model
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Unification Models of Active Galactic Nuclei postulate that all the observed differences between type 1 and type 2 objects are due to orientation effects with respect to the line of sight to the observer. The key ingredient of these models is the obscuring medium, historically envisaged as a toroidal structure on a parsec scale.
Stefano Bianchi +3 more
wiley +1 more source
The Role of Gravitational Instabilities in the Feeding of Supermassive Black Holes
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 I review the recent progresses that have been obtained, especially through the use of high‐resolution numerical simulations, on the dynamics of self‐gravitating accretion discs. A coherent picture is emerging, where the disc dynamics is controlled by a small number of parameters that determine whether the disc is stable or unstable, whether the ...
Giuseppe Lodato, Francesco Shankar
wiley +1 more source
Kinematical Conformal Cosmology: Fundamental Parameters from Astrophysical Observations
International Scholarly Research Notices, Volume 2011, Issue 1, 2011., 2011 We continue the presentation of an alternative cosmology based on conformal gravity, following our kinematical approach to the subject introduced in a recent paper. In line with the assumptions of our model, which proposes a closed‐form expression for the cosmic scale factor R(t), we revise the Hubble and deceleration parameters and introduce modified ...
Gabriele U. Varieschi +2 more
wiley +1 more source
Rotationally Inelastic Scattering of Formaldehyde
Laser Chemistry, Volume 5, Issue 6, Page 375-384, 1986., 1986 State to state rotationally inelastic and elastic differential cross‐sections for the system D2CO‐H2 have been measured at a center of mass energy of 17 meV. A single rotational state of D2CO (110) of high state purity is focused into the scattering region by combining rotational cooling and electric state selection.
N. F. Van Hulst +2 more
wiley +1 more source