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We have compared the occurrence of 6.7-GHz and 12.2-GHz methanol masers with 22-GHz water masers and 6035-MHz excited-state OH masers in the 100 square degree region of the southern Galactic plane common to the Methanol Multibeam (MMB) and…

The Central Molecular Zone (CMZ) spans the inner ~450 pc (3 degrees) of our Galaxy. This region is defined by its enhanced molecular emission and contains 5% of the entire Galaxy's molecular gas mass. However, the number of detected star…

星系天体物理 · 物理学 2019-01-16 Matthew Rickert , F. Yusef-Zadeh , J. Ott

Dicke superradiance describes an ensemble of $N$ permutationally invariant two-level systems collectively emitting radiation with a peak radiated intensity scaling as $N^2$. Although individual Dicke states are typically entangled, the…

量子物理 · 物理学 2026-03-27 Nico S. Bassler

We present results of the investigations of the properties of the methanol $J_1 - J_0$ A$^{-+}$ line series motivated by the recent serendipitous detection of the maser emission in the $14_1 - 14_0$ A$^{-+}$ line at 349~GHz in S255IR-SMA1…

星系天体物理 · 物理学 2022-03-30 Svetlana V. Salii , Igor I. Zinchenko , Sheng-Yuan Liu , Andrej M. Sobolev , Artis Aberfelds , Yu-Nung Su

The University of Tasmania Mt Pleasant 26-m and Ceduna 30-m radio telescopes have been used to search for 6.7-GHz class II methanol masers towards two hundred GLIMPSE sources. The target regions were selected on the basis of their…

天体物理学 · 物理学 2008-11-26 S. P. Ellingsen

Dicke superradiance is an example of emergence of macroscopic quantum coherence via correlated dissipation. Starting from an initially incoherent state, a collection of excited atoms synchronizes as they decay, generating a macroscopic…

量子物理 · 物理学 2022-05-27 Stuart J Masson , Ana Asenjo-Garcia

We report on EVN imaging of the 6.7 GHz methanol maser emission from the candidate high-mass protostar G23.657-0.127. The masers originate in a nearly circular ring of 127 mas radius and 12 mas width. The ring structure points at a central…

天体物理学 · 物理学 2016-08-30 A. Bartkiewicz , M. Szymczak , H. J. van Langevelde

Methanol masers at 6.7 GHz have been found exclusively towards high-mass star forming regions. Recently, some Class 0 protostars have been found to display conditions similar to what are found in hot cores that are associated with massive…

天体物理学 · 物理学 2009-11-13 J. D. Pandian , S. Leurini , K. M. Menten , A. Belloche , P. F. Goldsmith

6.7 GHz methanol maser emission from the well-studied star-forming region Cepheus A was monitored with the Torun 32 m radio telescope. We found synchronized and anticorrelated changes of the flux density of the two blueshifted and one…

星系天体物理 · 物理学 2014-03-05 M. Szymczak , P. Wolak , A. Bartkiewicz

We have used the ATNF Mopra antenna and the SEST antenna to search in the directions of several class II methanol maser sources for emission from six methanol transitions in the frequency range 85-115 GHz. The transitions were selected from…

天体物理学 · 物理学 2015-06-24 D. M. Cragg , A. M. Sobolev , S. P. Ellingsen , J. L. Caswell , P. D. Godfrey , S. V. Salii , R. G. Dodson

We have used the Australia Telescope Compact Array (ATCA) to search for continuum emission toward three strong 6.7-GHz methanol maser sources. For two of the sources, G339.88-1.26 and NGC 6334F (G351.42+0.64), we detect continuum emission…

天体物理学 · 物理学 2015-06-24 S. P. Ellingsen , R. P. Norris , P. M. McCulloch

Intriguing work on observations of 4.83 GHz formaldehyde (H2CO) absorptions and 4.87 GHz H110a radio recombination lines (RRLs) towards 6.7 GHz methanol (CH3OH) maser sources is presented. Methanol masers provide ideal sites to probe the…

太阳与恒星天体物理 · 物理学 2015-06-18 Daniel. Okoh , Jarken. Esimbek , Jian. Jun. Zhou , Xin. Di. Tang , Augustine. Chukwude , Johnson. Urama , Pius. Okeke

Dicke superradiance in ordered atomic arrays is a phenomenon where atomic synchronization gives rise to a burst in photon emission. This superradiant burst only occurs if there is one -- or just a few -- dominant decay channels. For a fixed…

量子物理 · 物理学 2024-09-12 Eric Sierra , Stuart J. Masson , Ana Asenjo-Garcia

We argue that the periodic variability of Class II methanol masers can be explained by variations of the dust temperature in the accretion disk around proto-binary star with at least one massive component. The dust temperature variations…

星系天体物理 · 物理学 2014-08-27 S. Yu. Parfenov , A. M. Sobolev

General characteristics of methanol (CH3OH) maser emission are summarized. It is shown that methanol maser sources are concentrated in the spiral arms. Most of the methanol maser sources from the Perseus arm are associated with embedded…

The effect of a newly born star cluster inside a giant molecular cloud (GMC) is to produce a hot bubble and a thin, dense shell of interstellar gas and dust swept up by the H II expansion, strong stellar winds, and repeated supernova…

天体物理学 · 物理学 2009-11-13 Lihong Yao , T. A. Bell , S. Viti , J. A. Yates , E. R. Seaquist

The 6.7 GHz methanol maser is exclusively associated with high-mass star formation. However, it remains unclear what structures harbour the methanol masers. Cepheus A is one of the closest regions of massive star formation, making it an…

太阳与恒星天体物理 · 物理学 2015-05-20 K. J. E. Torstensson , H. J. van Langevelde , W. H. T. Vlemmings , S. Bourke

We observed 14 methanol transitions near lambda=2 mm in Galactic star-forming regions. Broad, quasi-thermal J(0)-J(-1)E methanol lines near 157 GHz were detected toward 73 sources. Together with the 6(-1)-5(0)E and 5(-2)-6(-1)E lines at 133…

天体物理学 · 物理学 2009-10-31 V. I. Slysh , S. V. Kalenskii , I. E. Val'tts , V. V. Golubev , K. Mead

We present a continuing study of a sample 44 molecular outflows, observed in 13CO lines, closely associated with 6.7GHz methanol masers, hence called Methanol Maser Associated Outflows (MMAOs). We compare MMAO properties with those of…

The 6.7 GHz methanol maser emission, a tracer of forming massive stars, sometimes shows enigmatic periodic flux variations over several 10-100 days. In this Letter, we propose that this periodic variations could be explained by the…

太阳与恒星天体物理 · 物理学 2015-06-15 Kohei Inayoshi , Koichiro Sugiyama , Takashi Hosokawa , Kazuhito Motogi , Kei E. I. Tanaka