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相关论文: Understanding hydrogen recombination line observat…

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We present observations of the H91$\alpha$ recombination line emission towards a sample of nine HII regions associated with 6.7-GHz methanol masers, and report arcsecond-scale emission around compact cores. We derive physical parameters for…

天体物理学 · 物理学 2009-11-11 Stanislav Shabala , Simon Ellingsen , Stan Kurtz , Larry Forbes

The Atacama Large Millimeter/submillimeter Array (ALMA) offers new diagnostic capabilities for studying the Sun, providing complementary insights through high spatial and temporal resolution at millimeter wavelengths. ALMA acts as a linear…

We report on Atacama Large Millimeter/submillimeter Array (ALMA) detections of molecular absorption lines in Bands 3, 6 and 7 toward four radio-loud quasars, which were observed as the bandpass and complex gain calibrators. The absorption…

星系天体物理 · 物理学 2015-12-16 Ryo Ando , Kotaro Kohno , Yoichi Tamura , Takuma Izumi , Hideki Umehata , Hiroshi Nagai

The Atacama Large Millimeter/submillimeter Array (ALMA) was used in 2021 to image the carbon-rich evolved star R Lep in Bands 8-10 (397-908 GHz) with baselines up to 16 km. The goal was to validate the calibration, using band-to-band (B2B)…

New public numerical code for fast calculations of the cosmological recombination of primordial hydrogen-helium plasma is presented. The code is based on the three-level approximation (TLA) model of recombination and allows us to take into…

宇宙学与河外天体物理 · 物理学 2015-05-27 Evgeny E. Kholupenko , Alexandre V. Ivanchik , Sergey A. Balashev , Dmitry A. Varshalovich

High resolution 7 mm observations of the W49N massive star forming region have detected recombination line emission from the individual ultracompact (UC) HII regions on 50 milliarcsecond (600 AU) scales. These line observations, combined…

天体物理学 · 物理学 2009-11-10 C. G. De Pree , D. J. Wilner , A. J. Mercer , L. E. Davis , W. M. Goss , S. Kurtz

Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars.…

太阳与恒星天体物理 · 物理学 2017-11-28 Thomas Nordlander , Karin Lind

High resolution observations in the region of the lines Halpha, He II 4686 and Hgamma of the spectrum of the symbiotic binary Z And were performed during its small-amplitude brightening at the end of 2002. The profiles of the hydrogen lines…

太阳与恒星天体物理 · 物理学 2015-05-18 N. A. Tomov , M. T. Tomova , D. V. Bisikalo

Motivated by recent experiments on radiative recombination of two-dimensional electrons in acceptor doped GaAs-AlGaAs heterojunctions as well as the success of a harmonic solid model in describing tunneling between two-dimensional electron…

强关联电子 · 物理学 2016-08-31 S. Kodiyalam , H. A. Fertig , S. Das Sarma

Temporal variation of millimeter lines is a new direction of research for evolved stars. It has the potential to probe the dynamical wind launching processes from time dimension. We report here the first ALMA (Atacama Large Millimeter…

太阳与恒星天体物理 · 物理学 2019-10-09 J. H. He , T. Kamiński , R. E. Mennickent , V. I. Shenavrin , Diego Mardones , Wei Wang , Baitian Tang , M. R. Schmidt , R. Szczerba , Jixing. Ge

The unprecedented quality of the observations available from the Atacama Large Millimetre/sub-millimetre Array (ALMA) calls for analysis methods making the best of them. Reconstructing in space the morphology and kinematics of radio sources…

太阳与恒星天体物理 · 物理学 2016-09-07 P. N. Diep , N. T. Phuong , D. T. Hoai , P. T. Nhung , N. T. Thao , P. Tuan-Anh , P. Darriulat

There are few data available with which to constrain the thermal history of the intergalactic medium (IGM) following global recombination. Thus far, most constraints flow from analyses of the Cosmic Microwave Background and optical…

宇宙学与河外天体物理 · 物理学 2012-01-10 L. J. Greenhill , G. Bernardi

We present observations of a solar plage in the millimeter-continuum with the ALMA and in the Ca 8542 and Na 5896 spectral lines with the Interferometric BIdimensional Spectrometer (IBIS). Our goal is to compare the measurement of local gas…

太阳与恒星天体物理 · 物理学 2022-07-27 Ryan Hofmann , Kevin Reardon , Ivan Milic , Momchil Molnar , Yi Chai , Han Uitenbroek

We present high sensitivity H91$\alpha$ and 3.5 cm radio continuum observations toward the planetary nebula NGC 3242. The electron temperature determined assuming local thermodynamic equilibrium is consistent within $\sim$10% with that…

星系天体物理 · 物理学 2009-11-04 Luis F. Rodriguez , Yolanda Gomez , J. Alberto Lopez , Ma. Teresa Garcia-Diaz , David M. Clark

We present ALMA cycle 0 observations of the molecular gas and dust in the IR-bright mid-stage merger VV114 obtained at 160 - 800 pc resolution. The main aim of this study is to investigate the distribution and kinematics of the cold/warm…

The 2s_{1/2} state of hydrogen is metastable and overpopulated in HII regions. In addition, the 2p states may be pumped by ambient Lyman-alpha radiation. Fine structure transitions between these states may be observable in HII regions at…

天体物理学 · 物理学 2009-11-11 Brian Dennison , B. E. Turner , Anthony H. Minter

Cosmological constraints from the cosmic microwave background (CMB) anisotropies rely on accurate theoretical calculations of the cosmic recombination history. Recent work has emphasized the importance of radiative transfer calculations due…

宇宙学与河外天体物理 · 物理学 2014-11-18 Christopher M. Hirata , John Forbes

The Lyman alpha (lya) line of Hydrogen is a prominent feature in the spectra of star-forming galaxies, usually redshifted by a few hundreds of km/s compared to the systemic redshift. This large offset hampers follow-up surveys, galaxy pair…

We use state-of-the-art radiation-MHD simulations and 3D non-LTE radiative transfer computations to investigate \Halpha\ line formation in the solar chromosphere and apply the results of this investigation to develop the potential of…

太阳与恒星天体物理 · 物理学 2015-06-04 Jorrit Leenaarts , Mats Carlsson , Luc Rouppe van der Voort

Aims. Studying protostellar objects in their earliest stages, particularly during the Class 0 phase, provides key insight into the beginnings of planet formation and dust evolution. Disentangling the various components, however, is…