Results 31 to 40 of about 1,861,445 (361)
Emission-line diagnostics of nearby H ii regions including interacting binary populations [PDF]
, 2018 We present numerical models of the nebular emission from H II regions around young stellar populations over a range of compositions and ages. The synthetic stellar pop- ulations include both single stars and interacting binary stars.
Lin Xiao, E. Stanway, J. J. Eldridge
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Radiation Hydrodynamics of Turbulent H ii Regions in Molecular Clouds: A Physical Origin of LyC Leakage and the Associated Lyα Spectra [PDF]
Astrophysical Journal, 2019 We examine Lyman continuum (LyC) leakage through H ii regions regulated by turbulence and radiative feedback in a giant molecular cloud in the context of fully coupled radiation hydrodynamics (RHD).
K. Kakiichi, M. Gronke
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Symposium - International Astronomical Union, 1973 The observed far infrared flux of H II regions is interpreted as evidence for the presence of internal dust absorbing a fraction of Lyman continuum photons. The effect of this dust on the required number of ionizing photons and on the helium to hydrogen line intensity ratios are discussed and analytic formulae describing these effects are presented for
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Spectroscopy of Outlying H II Regions in Spiral Galaxies: Abundances and Radial Gradients [PDF]
, 1998 We present the results of low-dispersion optical spectroscopy of 186 H II regions spanning a range of radius in 13 spiral galaxies. Abundances for several elements (oxygen, nitrogen, neon, sulfur, and argon) were determined for 185 of the H II regions ...
L. van Zee +4 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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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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New calibrations for abundance determinations in H ii regions [PDF]
, 2016 Simple relations for deriving the oxygen abundance in HII regions with intensities of the three strong emission lines R_2, R_3, and N_2 (R calibration) or S_2, R_3, and N_2 (S calibration) in their spectra are suggested.
L. Pilyugin +3 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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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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Surveying the Giant H ii Regions of the Milky Way with SOFIA. I. W51A [PDF]
Astrophysical Journal, 2019 We discuss the first results from our mid-infrared (MIR) imaging survey of Milky Way Giant H ii (GH ii) regions with our detailed analysis of W51A, which is one of the largest GH ii regions in our Galaxy.
W. Lim, J. D. De Buizer
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