Results 11 to 20 of about 590 (185)
Planetary Nebulae and the Ionization of the Interstellar Medium in Galaxies
Frontiers in Astronomy and Space Sciences, 2022 We discuss the role of planetary nebulae and their progeny in galaxy context in terms of ionization of the galaxy interstellar medium. This regards ionized gas outside the disk of spiral galaxies, the diffuse ionized medium in spiral galaxies, and the ...
Grażyna Stasińska +2 more
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Spatially Resolved Temperature and Density Structures of Nearby H ii Regions
The Astrophysical Journal, 2023 Photoionization models frequently assume constant temperature or density within H ii regions. We investigate this assumption by measuring the detailed temperature and density structures of four H ii regions in the Large Magellanic Cloud and the Small ...
Yifei Jin +3 more
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SATELLITE: Application to Planetary Nebulae IFU Data
Galaxies, 2022 The integral field unit (IFU) spectroscopic view of extended ionized nebulae, such as planetary nebulae (PNe), H II regions, and galaxies, has changed the approach of studying these objects, providing a simultaneous characterization in both spatial ...
Stavros Akras +5 more
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The Astrophysical Journal, 1993 The formation and destruction processes of HeH + in nebulae are discussed, and calculations of the abundances of HeH + are presented. It is shown that for effective temperatures of the ionizing source exceeding 50,000 K, the abundances are of the order of 10 12 cm −2 , largely independent of the nebular parameters.
C. Cecchi-Pestellini, A. Dalgarno
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Emission Nebulae as Radio Sources [PDF]
Australian Journal of Physics, 1956 Attempts have been made to detect 14 bright emission nebulae at a wavelength of 3?5 m using a pencil-beam radio telescope with a beamwidth of 50 min of arc. Of these nebulae, six were probably observed in emission, seven were undetectable, and one, NGC 6357, was observed in absorption; radio isophotes were obtained for NGC 2237 and NGC 3372.
BY Mills, AG Little, KV Sheridan
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The morphology of dust emission in Planetary Nebulae and proto-Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1997 This review covers recent results from ground based mid-infrared (mid–IR; 8–25μm) imaging of thermal dust emission. The mid–IR images of proto–PNe show evidence for axially symmetric superwinds. In young PNe, the dust appears to be well mixed with the gas in the ionized gas regions.
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The Continuum Emission from Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1988 The study of nebular continuum emission is important for several reasons (Pottasch 1984, Planetary Nebulae, Dordrecht: Reidel). First of all, it can provide information about the temperature and the density of the nebula, when the object is large enough, or when the central star is weak enough, so that the nebular continuum is easily observed without ...
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On the integrated continuum radio spectrum of supernova remnant W44 (G34.7-0.4): New insights from Planck [PDF]
Serbian Astronomical Journal, 2015 In this paper, the integrated continuum radio spectrum of supernova remnant (SNR) W44 was analyzed up to 70 GHz, testing the different emission models that can be responsible for its particular shape.
Onić D.
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The contribution of Galactic TeV pulsar wind nebulae to Fermi large area telescope diffuse emission
Communications Physics, 2022 Cosmic Rays (CRs) with energy below 1 PeV are believed to originate in the Milky Way, but recent gamma-ray observations by Fermi Large Area Telescope challenge the interpretation of CR diffusion mechanisms across the galaxy.
Vittoria Vecchiotti +2 more
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Galaxies, 2020 We present the first results from comprehensive, near-UV-to-near-IR Hubble Space Telescope Wide Field Camera 3 (WFC3) emission-line imaging studies of two young planetary nebulae (PNe), NGC 7027 and NGC 6302.
Joel H. Kastner +5 more
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