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Identification of a turnover in the initial mass function of a young stellar cluster down to 0.5 MJ
De Furio M +13 more
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Radio Emission of Planetary Nebulae [PDF]
, 1997 A planetary nebula, is essentially a cloud of strongly ionized gas, and so the emission at radio frequencies should be inevitable. Continuous radio emission should be excited mainly by free—free transitions of electrons in the Coulomb field of charged particles. In this case, the total energy emitted at radio frequencies is proportional to ∫ n e 2 dV ~
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Visualizing Stars and Emission Nebulas
Computer Graphics Forum, 2001We describe star and nebula visualization techniques used to create a 3D volumetric visualization of the Orion Nebula. The nebula's ionization layer is modeled first as a surface model, derived from infrared and visible light observations. The surface model is imported into a volume scene graph‐based visualization system that uses procedural volume ...
Erik Wesselak +6 more
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Publications of the Astronomical Society of the Pacific, 1979
Two hundred and fifty-two H II regions have been identified in NGC 4449 and positions in rectangular coordinates are given. The size-frequency relation is compared with that of M33, NGC 2403, NGC 628, NGC 3631, and NGC 6822. Very sharp and faint filaments radially arranged with respect to the main body of the galaxy have been identified.
F. Sabbadin, Antonio Bianchini
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Two hundred and fifty-two H II regions have been identified in NGC 4449 and positions in rectangular coordinates are given. The size-frequency relation is compared with that of M33, NGC 2403, NGC 628, NGC 3631, and NGC 6822. Very sharp and faint filaments radially arranged with respect to the main body of the galaxy have been identified.
F. Sabbadin, Antonio Bianchini
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Infrared Emission from Reflection Nebulae [PDF]
Symposium - International Astronomical Union, 1989 Observations of 1–25 μm. continuum emission and the interstellar infrared emission features in reflection nebulae are reviewed. These observations place important constraints on models of very small grains or large molecules such as PAHs, which these models must address in order to understand this fundamental component of interstellar dust.
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On the groups of diffuse emission nebulae
Vistas in Astronomy, 1956Abstract We have distinguished twenty-one groups of emission nebulae which seem to represent real concentrations in space. Some tendency to clustering for emission nebulae and patches may be also suggested in some extragalactic nebulae. The groups of emission nebulae are probably real fluctuations in spiral arms. It is suggested that the total energy
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The Planetary Nebula A 79 Revisited: Discovery of a Large Emission Nebula
Astrophysics and Space Science, 2002New observations of the planetary nebula A 79 using selective interference filters (Δ λ ≤ 10 A) are reported. Thanks to the large field of view (< 11″5) offered by the Observatoire de Haute Provence 120-cm telescope we were able to discover a new extended feature close to A 79.
Jacqueline Martinis, Hua Chon-Trung
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3D Spectroscopy of Emission Nebulae
2009Emission nebulae like H II regions, Planetary Nebulae, Novae, Herbig Haro objects etc. are found as extended objects in the Milky Way, but also as point sources in other galaxies, where they are sometimes observable out to very large distances due to the high contrast provided by some prominent emission lines.
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