Results 11 to 20 of about 154 (145)
The Astrophysical Journal Supplement Series, 2023 We present a statistical study of infrared variability using the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) database for a sample consisting of 1085 high-mass young stellar objects (YSOs) related to 6.7 GHz methanol masers.
Shi-Min Song +8 more
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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
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New interstellar masers in nonmetastable ammonia
The Astrophysical Journal, 1986 The published version is located at http://adsabs.harvard.edu/full/1986ApJ...300L ...
MADDEN, SC +4 more
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Interstellar methanol masers [PDF]
Symposium - International Astronomical Union, 1993 The asymmetric rotor molecule methanol (CH3OH) has hundreds of transitions at centimeter-, millimeter-, and submillimeter wavelengths. Many of these are excited in the hot (T ≳ 150 K), dense (n ≳ 106 cm−3) molecular cloud cores surrounding newly formed massive stars or protostars.
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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
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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
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Variability of interstellar hydroxyl masers
The Astrophysical Journal, 1991 The spectra of 10 interstellar OH maser complexes were monitored in the 1665 MHz transition for variability on short (minutes-hours) and long (days-years) time scales. Eight of the sources exhibit short time scale variability in the relative amplitudes of the spectral features above that expected due to radiometer noise, and all sources for which ...
Andrew W. Clegg, James M. Cordes
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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
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