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Related papers: Modelling of aspherical nebulae. I. A quick pseudo…

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We describe the incorporation of polarized radiative transfer into the atmospheric radiative transfer modelling code VSTAR (Versatile Software for Transfer of Atmospheric Radiation). Using a vector discrete-ordinate radiative transfer code…

Earth and Planetary Astrophysics · Physics 2018-08-01 Jeremy Bailey , Lucyna Kedziora-Chudczer , Kimberly Bott

We study the effects of using the optical properties of irregular hexahedral grains in photoionization models of circumstellar nebulae around evolved stars. Dust opacities for the irregular grains were obtained from the scattering…

Astrophysics of Galaxies · Physics 2026-04-13 P. Jiménez-Hernández , S. J. Arthur , D. Guirado , O. Muñoz , J. Martikainen , L. Sabin , W. J. Henney

This paper - the first of a short series dedicated to the long-stan ding astronomical problem of de-projecting the bi-dimensional apparent morpholog y of a three-dimensional mass of gas - focuses on the density distribution in real…

Astrophysics · Physics 2009-11-11 F. Sabbadin , M. Turatto , R. Ragazzoni , E. Cappellaro , S. Benetti

Optical integral-field spectroscopy was used to investigate the planetary nebula NGC 3242. We analysed the main morphological components of this source, including its knots, but not the halo. In addition to revealing the properties ofthe…

Astrophysics of Galaxies · Physics 2015-06-17 H. Monteiro , D. R. Gonçalves , M. L. Leal-Ferreira , R. L. M. Corradi

Continuing our series of papers on the 3-D structure and accurate distances of Planetary Nebulae (PNe), we present here the results obtained for the planetary nebula NGC\,40. Using data from different sources and wavelengths, we construct…

Solar and Stellar Astrophysics · Physics 2015-05-28 Hektor Monteiro , Diego Falceta-Gonçalves

Semiconductor devices are scaled down to the level which constituent materials are no longer considered continuous. To account for atomistic randomness, surface effects and quantum mechanical effects, an atomistic modeling approach needs to…

Computational Physics · Physics 2015-03-13 Sunhee Lee , Hoon Ryu , Zhengping Jiang , Gerhard Klimeck

Observations of some starburst-driven galactic superwinds suggest that strong radiative cooling could play a key role in the nature of feedback and the formation of stars and molecular gas in star-forming galaxies. These catastrophically…

Astrophysics of Galaxies · Physics 2022-09-30 A. Danehkar , M. S. Oey , W. J. Gray

We explore the formation of multipolar structures in planetary and pre-planetary nebulae from the interaction of a fast post-AGB wind with a highly inhomogeneous and filamentary shell structure assumed to form during the final phase of the…

Solar and Stellar Astrophysics · Physics 2015-06-16 W. Steffen , N. Koning , A. Esquivel , G. Garcia-Segura , Ma. T. Garcia-Diaz , J. A. Lopez , M. Magnor

We present some results of an on-going project aimed at studying a sample of Galactic HII regions ionized by a single massive star to test the predictions of modern generation stellar atmosphere codes in the H Lyman continuum. The…

Astrophysics · Physics 2008-02-04 S. Simón-Díaz , J. García-Rojas , G. Stasińska , C. Esteban

Focused electron beam induced deposition (FEBID) is a powerful technique for 3D-printing of complex nanodevices. However, for resolutions below 10 nm, it struggles to control size, morphology and composition of the structures, due to a lack…

Nebular emission lines associated with galactic HII regions carry information about both physical properties of the ionised gas and the source of ionising photons as well as providing the opportunity of measuring accurate redshifts and thus…

We present hydrodynamical simulations of the photoevaporation of a cloud with large-scale density gradients, giving rise to an ionized, photoevaporation flow. The flow is found to be approximately steady during the large part of its…

Astrophysics · Physics 2009-11-11 W. J. Henney , S. J. Arthur , Ma. T. Garcia-Diaz

We present a powerful new tool to analyse and disentangle the 3-D geometry and kinematic structure of gaseous nebulae. The method consists in combining commercially available digital animation software to simulate the 3-D structure and…

Astrophysics · Physics 2007-05-23 Wolfgang Steffen , Jose Alberto Lopez

We present new narrow-band filter imagery in H-alpha and [N II] 6584 along with UV and optical spectrophotometry measurements from 1200 to 9600 Angstroms of NGC 7293, the Helix Nebula, a nearby, photogenic planetary nebula of large diameter…

Astrophysics · Physics 2009-10-31 R. B. C. Henry , K. B. Kwitter , R. J Dufour

[Abridged] Investigations of neutron(n)-capture element nucleosynthesis and chemical evolution have largely been based on stellar spectroscopy. However, the recent detection of these elements in several planetary nebulae (PNe) indicates…

We present an analysis of physical conditions in planetary nebulae (PNe) in terms of collisionally-excited line (CEL) and optical-recombination line (ORL) profiles. We aim to investigate whether line profiles could be used to study the…

Astrophysics · Physics 2009-11-13 Yong Zhang

We have developed a theoretical method for interpretation of photoionization experiments with the H_3 molecule. In the present study we give a detailed description of the method, which combines multichannel quantum defect theory, the…

Atomic Physics · Physics 2009-11-10 Viatcheslav Kokoouline , Chris H. Greene

LiDAR and camera are two essential sensors for 3D object detection in autonomous driving. LiDAR provides accurate and reliable 3D geometry information while the camera provides rich texture with color. Despite the increasing popularity of…

Computer Vision and Pattern Recognition · Computer Science 2023-08-21 Qi Jiang , Hao Sun , Xi Zhang

The shape of the ionising spectra of galaxies is a key ingredient to reveal their physical properties and to our understanding of the ionising background radiation. A long-standing unsolved problem is the presence of HeII nebular emission…

Astrophysics of Galaxies · Physics 2021-12-11 Charlotte Simmonds , Daniel Schaerer , Anne Verhamme

The narrow line region of active galaxies is formed by gas clouds surrounded by a diluted gas. Standard one-dimensional photoionization models are usually used to model this region in order to reproduce the observed emission lines. Since…

Astrophysics · Physics 2009-11-07 Lucimara P. Martins , Sueli M. Viegas , Ruth Gruenwald
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