Results 21 to 30 of about 1,094,944 (319)
PHANGS–JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE
The Astrophysical Journal Letters, 2023 Polycyclic aromatic hydrocarbons (PAHs) play a critical role in the reprocessing of stellar radiation and balancing the heating and cooling processes in the interstellar medium but appear to be destroyed in H ii regions.
Oleg V. Egorov +32 more
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The Chocolate Chip Cookie Model: Dust-to-metal Ratio of H ii Regions
The Astrophysical Journal Letters, 2023 Using a sample of face-on star-forming galaxies selected from the Sloan Digital Sky Survey, we statistically derive the typical optical depth τ _cl of individual H ii regions based on the “Chocolate Chip Cookie” model of Lu et al. (2022).
Jiafeng Lu +3 more
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H II regions with He II emission [PDF]
Publications of the Astronomical Society of the Pacific, 1991 H II regions which exhibit surprisingly strong nebular He II λ4686 emission, with I(λ4686)/I (Hβ) as high as 0.3 in some cases. The He II emission in-these objects is associated with a rather diverse set of stars, with WO stars, very early WN stars, and luminous X-ray binaries involved, and in one case what appears to be a normal O-type star. Extension
Donald R. Garnett +3 more
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Properties of H II region populations in galaxies. II - The H II region luminosity function
The Astrophysical Journal, 1989 H-alpha emission-line fluxes have been measured for all of the detected H II regions in 30 nearby spiral and irregular galaxies, and these data are used to study the behavior of the H II region luminosity functions (LFs). In most galaxies, the LF is well represented by a power law function.
Robert C., Jr. Kennicutt +2 more
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Astronomy & Astrophysics, 2018 Aims. We aim to identify bipolar Galactic H II regions and to understand their parental cloud structures, morphologies, evolution, and impact on the formation of new generations of stars. Methods. We use the Spitzer-GLIMPSE, Spitzer-MIPSGAL, and Herschel-Hi-GAL surveys to identify bipolar H II regions and to examine their morphologies.
Samal, M. +5 more
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Searching for Galactic H ii Regions from the LAMOST Database Based on the Multihead WDCNN Model
The Astrophysical Journal Supplement Series, 2023 A H ii region is a kind of emission nebula, and more definite samples of H ii regions can help study the formation and evolution of galaxies. Hence, a systematic search for H ii regions is necessary.
Mengxin Wang +3 more
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Diffuse continuum transfer in H���ii regions [PDF]
Monthly Notices of the Royal Astronomical Society, 2009 12 pages, 7 figures, to be published in ...
Williams, R. J. R., Henney, W. J.
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Ionized gas kinematics in bipolar H ii regions [PDF]
Monthly Notices of the Royal Astronomical Society, 2018 14 pages and 9 figures.
Hannah S Dalgleish +5 more
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Massive Star Formation in the Ultraviolet Observed with the Hubble Space Telescope
Galaxies, 2020 Spectroscopic observations of a massive star formation in the ultraviolet and their interpretation are reviewed. After a brief historical retrospective, two well-studied resolved star clusters and the surrounding H II regions are introduced: NGC 2070 in ...
Claus Leitherer
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The Astrophysical JournalWe employ observations of the 205 μ m [N ii ] fine structure (FS) line and radio recombination line (RRL) emission to derive the electron density in 10 well-known H ii regions. The combination of these two spectral lines (the RRL–FS line method) provides
Paul. F. Goldsmith +4 more
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