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Related papers: Modelling CH$_3$OH masers: Sobolev approximation a…

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We derive accurate proper motions of the CH3OH 12 GHz masers towards the W3(OH) UCHII region, employing seven epochs of VLBA observations spanning a time interval of about 10 yr. The achieved velocity accuracy is of the order of 0.1 km/s,…

Solar and Stellar Astrophysics · Physics 2015-05-18 Luca Moscadelli , Ye Xu , Xi Chen

We propose a modified version of the three-step estimation method for the latent class model with covariates, which may be used to estimate latent Markov models for longitudinal data. The three-step estimation approach we propose is based…

Methodology · Statistics 2014-02-06 Francesco Bartolucci , Giorgio E. Montanari , Silvia Pandolfi

We detail interferometric observations of 44GHz class I methanol masers detected by MALT-45 (a 7mm unbiased auto-correlated spectral-line Galactic-plane survey) using the Australia Telescope Compact Array. We detect 238 maser spots across…

Molecular-orbital-based machine learning (MOB-ML) enables the prediction of accurate correlation energies at the cost of obtaining molecular orbitals. Here, we present the derivation, implementation, and numerical demonstration of MOB-ML…

Chemical Physics · Physics 2021-04-07 Sebastian J. R. Lee , Tamara Husch , Feizhi Ding , Thomas F. Miller

We investigate the application of the conventional quasi-steady state maser modelling algorithm of Menegozzi & Lamb (ML) to the high field transient regime of the one-dimensional Maxwell-Bloch (MB) equations for a velocity distribution of…

Instrumentation and Methods for Astrophysics · Physics 2021-08-04 C. M. Wyenberg , B. Lankhaar , F. Rajabi , M. A. Chama , M. Houde

This work presents a study of the milliarcsecond structure of the 6.7 GHz methanol masers at high-velocity resolution (0.09 km s^(-1)) in four high-mass star-forming regions: G16.59-0.05, G23.01-0.41, IRAS20126+4104, and AFGL5142. We…

Solar and Stellar Astrophysics · Physics 2015-05-30 Luca Moscadelli , Alberto Sanna , Ciriaco Goddi

We report the results of our systematic survey for Galactic 6.7 GHz Class II CH$_3$OH maser emission toward a sample of young stellar objects. The survey was conducted with the Shanghai Tianma Radio Telescope (TMRT). The sample consists of…

Astrophysics of Galaxies · Physics 2019-06-14 Kai Yang , Xi Chen , Zhi-Qiang Shen , Xiao-Qiong Li , Jun-Zhi Wang , Dong-Rong Jiang , Juan Li , Jian Dong , Ya-Jun Wu , Hai-Hua Qiao

The first images of 6.7-GHz methanol masers in the massive star-forming regions DR21(OH) and DR21(OH)N are presented. By measuring the shapes, radial velocities and polarization properties of these masers it is possible to map out the…

Astrophysics · Physics 2009-11-13 L. Harvey-Smith , R. Soria-Ruiz , A. Duarte-Cabral , R. J. Cohen

The interaction of hot atoms with laser fields experiences a Doppler shift which can severely affect the precise spatial measurement of an atom. We suggest an experimentally realizable scheme to address this issue in three-dimension…

Atomic Physics · Physics 2016-07-14 Rahmat Ullah , You-Lin Chuang , Ray-Kuang Lee , Sajid Qamar

The dramatic increase in sensitivity, spectral coverage and resolution of radio astronomical facilities in recent years has opened new possibilities for observation of chemical differentiation and isotopic fractionation in protostellar…

Instrumentation and Methods for Astrophysics · Physics 2021-04-30 Li-Hong Xu , R. M. Lees , O. Zakharenko , H. S. P. Müller , F. Lewen , S. Schlemmer , K. M. Menten

We have used the Australia Telescope Compact Array (ATCA) to make the first high resolution observations of a large sample of class~I methanol masers in the 95-GHz ($8_0$--$7_1$A$^+$) transition. The target sources consist of a…

Astrophysics of Galaxies · Physics 2018-03-28 Tiege P. McCarthy , Simon P. Ellingsen , Maxim A. Voronkov , Giuseppe Cimo

Multithreshold Entropy Linear Classifier (MELC) is a density based model which searches for a linear projection maximizing the Cauchy-Schwarz Divergence of dataset kernel density estimation. Despite its good empirical results, one of its…

Machine Learning · Computer Science 2015-04-21 Rafal Jozefowicz , Wojciech Marian Czarnecki

In the CERN NA63 collaboration we have addressed the question of the potential inadequacy of the commonly used Migdal formulation of the Landau-Pomeranchuk-Migdal (LPM) effect by measuring the photon emission by 20 and 178 GeV electrons in…

High Energy Physics - Experiment · Physics 2015-06-17 K. K. Andersen , S. L. Andersen , J. Esberg , H. Knudsen , R. E. Mikkelsen , U. I. Uggerhøj , T. N. Wistisen , P. Sona , A. Mangiarotti , T. J. Ketel

A 3D maser model has been used to perform an inverse problem on the light curves from three high-amplitude maser flares, selected on the basis of contemporaneous infra-red observations. Plots derived from the model recover the size of the…

Solar and Stellar Astrophysics · Physics 2020-07-08 M. D. Gray , S. Etoka , B. Pimpanuwat

We have used the Australian Long Baseline Array (LBA) to produce milliarcsecond images of five sites of methanol maser emission at 6.7 GHz. These are all sites that have linear morphologies at arcsecond resolutions, which have been…

Astrophysics · Physics 2009-11-10 R. Dodson , R. Ojha , S. P. Ellingsen

Direct-drive is an important approach to achieving the ignition of inertial confinement fusion. To enhance implosion performance while keeping the risk of hydrodynamic instability at a low level, we have designed a procedure to optimize the…

Plasma Physics · Physics 2022-09-07 Guannan Zheng , Tao Tao , Qing Jia , Rui Yan , Jian Zheng

The Linear Ballistic Accumulator (Brown & Heathcote, 2008) model is used as a measurement tool to answer questions about applied psychology. The analyses based on this model depend upon the model selected and its estimated parameters.…

Methodology · Statistics 2020-03-03 David Gunawan , Guy E. Hawkins , Minh-Ngoc Tran , Robert Kohn , Scott Brown

As the recent publication by Breen et al (2013) found Class II methanol masers are exclusively associated with high mass star forming regions. Based on the positions of the Class I and II methanol and H$_{2}$O masers, UC H II regions and…

Astrophysics of Galaxies · Physics 2014-11-19 Hontas Farmer

A means to take advantage of molecular similarity to lower the computational cost of electronic structure theory is proposed, in which parameters are embedded into a low-cost, low-level (LL) ab initio theory and adjusted to obtain agreement…

Chemical Physics · Physics 2013-11-15 Matteus Tanha , Shiva Kaul , Alex Cappiello , Geoffrey J. Gordon , David J. Yaron

We present 247-GHz molecular line observations of methanol (CH$_3$OH) toward sixteen massive star-forming regions, using the APEX telescope with an angular resolution of $25''$. The sample covers a range of evolutionary states, including…