A computer program for fast non-LTE analysis of interstellar line spectra
F. F. S. van der Tak,F. F. S. van der Tak,John H. Black,Fredrik L. Schöier,D. J. Jansen,E. F. van Dishoeck +5 more
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TLDR
In this paper, the authors present a computer program to calculate the intensities of atomic and molecular lines produced in a uniform medium, based on statistical equilibrium calculations involving collisional and radiative processes and including radiation from background sources.Abstract:
The large quantity and high quality of modern radio and infrared line observations require efficient modeling techniques to infer physical and chemical parameters such as temperature, density, and molecular abundances. We present a computer program to calculate the intensities of atomic and molecular lines produced in a uniform medium, based on statistical equilibrium calculations involving collisional and radiative processes and including radiation from background sources. Optical depth effects are treated with an escape probability method. The program is available on the World Wide Web at http://www.sron.rug.nl/~vdtak/radex/index.shtml . The program makes use of molecular data files maintained in the Leiden Atomic and Molecular Database (LAMDA), which will continue to be improved and expanded. The performance of the program is compared with more approximate and with more sophisticated methods. An Appendix provides diagnostic plots to estimate physical parameters from line intensity ratios of commonly observed molecules. This program should form an important tool in analyzing observations from current and future radio and infrared telescopes. Note: Accepted by AA 18 A4 pages, 11 figures;read more
Citations
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C+ detection of warm dark gas in diffuse clouds
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TL;DR: In this paper, the authors present the UH Research Archive for Astronomy & Astrophysics (UHRA) for personal research, educational, and non-commercial purposes only.
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Molecular line emission in NGC 1068 imaged with ALMA - II. The chemistry of the dense molecular gas
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TL;DR: In this article, a detailed analysis of Atacama Large Millimeter/submillimeter Array (ALMA) Bands 7 and 9 data of CO, HCO+, HCN, and CS, augmented with Plateau de Bure Interferometer (PdBI) data of the ~200 pc circumnuclear disc (CND) and the ~1.3 kpc starburst ring (SB ring) of NGC 1068, a nearby (D = 14 Mpc) Seyfert 2 barred galaxy.
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Gas fraction and star formation efficiency at z < 1.0
Francoise Combes,Santiago García-Burillo,Jonathan Braine,Eva Schinnerer,Fabian Walter,Luis Colina +5 more
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Journal ArticleDOI
Herschel Measurements of Molecular Oxygen in Orion
Paul F. Goldsmith,René Liseau,T. A. Bell,John H. Black,Jo Hsin Chen,David Hollenbach,Michael J. Kaufman,Di Li,Dariusz C. Lis,G. Melnick,David A. Neufeld,Laurent Pagani,Ronald L. Snell,Arnold O. Benz,Edwin A. Bergin,Simon Bruderer,Paola Caselli,Emmanuel Caux,Emmanuel Caux,Pierre Encrenaz,Edith Falgarone,Edith Falgarone,Maryvonne Gerin,Maryvonne Gerin,Javier R. Goicoechea,Åke Hjalmarson,Bengt Larsson,Jacques Le Bourlot,Franck Petit,Massimo De Luca,Zsofia Nagy,Evelyne Roueff,Aage Sandqvist,Floris van der Tak,Ewine F. van Dishoeck,Charlotte Vastel,Charlotte Vastel,Serena Viti,Umut A. Yildiz +38 more
TL;DR: In this article, the authors reported observations of three rotational transitions of molecular oxygen (O2) in emission from the H2 Peak 1 position of vibrationally excited molecular hydrogen in Orion.
References
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Book
Radiative processes in astrophysics
TL;DR: Inverse square law for a uniformly bright sphere as discussed by the authors is used to define specific intensity and its moments, which is defined as the specific intensity or brightness of a sphere in terms of specific intensity.
Journal ArticleDOI
An atomic and molecular database for analysis of submillimetre line observations
TL;DR: In this paper, atomic and molecular data for the transitions of a number of astrophysically interesting species are summarized, in-cluding energy levels, statistical weights, Einstein A-coefficients and collisional rate coefficients.
Journal ArticleDOI
An atomic and molecular database for analysis of submillimetre line observations
TL;DR: In this article, the transitions of a number of astrophysically interesting species are summarized, including energy levels, statistical weights, Einstein A-coefficients and collisional rate coefficients.
Journal ArticleDOI
Molecular abundances in OMC-1 - the chemical composition of interstellar molecular clouds and the influence of massive star formation
TL;DR: In this article, the chemical composition of the various regions in the core of the Orion molecular cloud (OMC-1) was investigated based on results from the Caltech Owens Valley Radio Observatory (OVRO) spectral line survey (Sutton et al., Blake et al.).
Journal ArticleDOI
Population Diagram Analysis of Molecular Line Emission
TL;DR: In this paper, the authors developed the use of the population diagram method to analyze molecular emission in order to derive physical properties of interstellar clouds, focusing particular attention on how the optical depth affects the derived total column density and the temperature.