Shape: A 3D Modeling Tool for Astrophysics

Steffen, W.; Koning, Nico; Wenger, Stephan; Morisset, Charles; Magnor, Marcus

doi:10.1109/tvcg.2010.62

Cited by 197 publications

(196 citation statements)

References 25 publications

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“…As a result, what can be generally measured is the product of a measure of the inclination, typically sin θ , by a measure of the elongation of the effective emissivity and/or velocities along the star axis. This result, which is well known for morphology (Steffen et al 2011;Leahy 1991;Palmer 1994, Magnor et al 2004& 2005 is also valid for kinematics. As detailed in Appendix A7, this implies strong correlations relating the inclination angle to the elongation of the outflow on the star axis, namely the ratio of polar to equatorial wind velocities.…”

Section: Inclination θ Of the Star Axis With Respect To The Line Of Ssupporting

confidence: 81%

Space reconstruction of the morphology and kinematics of axisymmetric radio sources

Diep¹,

Phượng²,

Hoai³

et al. 2016

Mon. Not. R. Astron. Soc.

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The unprecedented quality of the observations available from the Atacama Large Millimetre/sub-millimetre Array (ALMA) calls for analysis methods making the best of them. Reconstructing in space the morphology and kinematics of radio sources is an underdetermined problem that requires imposing additional constraints for its solution. The hypothesis of rotational invariance, which is a good approximation to, or at least a good reference for the description of the gas envelopes of many evolved stars and protostars, is particularly efficient in this role. In the first part of the article, a systematic use of simulated observations allows for identifying the main problems and for constructing quantities aimed at solving them. In particular the evaluation of the orientation of the star axis in space and the differentiation between expansion along the star axis and rotation about it are given special attention. The use of polar rather than Cartesian sky coordinates to display the results of the analysis is shown to often better match the morphology and kinematics of actual stars. The radial dependence of the gas density and temperature and the possible presence of velocity gradients are briefly considered. In the second part, these results are applied to a few stars taken as examples with the aim of evaluating their usefulness when applied to concrete cases. A third part takes stock of what precedes and formulates some guidelines for modelling the radio emission of axisymmetric radio sources, limited however to the mathematics and geometry of the problem, physics considerations being generally ignored.

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Section: Inclination θ Of the Star Axis With Respect To The Line Of Ssupporting

confidence: 81%

Space reconstruction of the morphology and kinematics of axisymmetric radio sources

Diep¹,

Phượng²,

Hoai³

et al. 2016

Mon. Not. R. Astron. Soc.

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“…To illustrate the scenario we proposed for the narrower component, we built a toy model of a rotating disk, two spiral arms and a biconical outflow using the software Shape (Steffen et al 2011). As the overall contribution of noncircular motions along the bar to the gaseous velocity field is unclear, we do not include the bar in our model.…”

Section: The Narrower Componentmentioning

confidence: 99%

Gas inflows towards the nucleus of the Seyfert 2 galaxy NGC 1667

Schnorr-Müller

Storchi‐Bergmann

Ferrari

et al. 2017

Mon. Not. R. Astron. Soc.

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We use optical spectra from the inner 2 × 3 kpc 2 of the Seyfert 2 galaxy NGC 1667, obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈ 240 pc, to assess the feeding and feedback processes in this nearby AGN. We have identified two gaseous kinematical components in the emission line profiles: a broader component (σ ≈ 400 km s −1 ) which is observed in the inner 1-2 ′′ and a narrower component (σ ≈ 200 km s −1 ) which is present over the entire field-ofview. We identify the broader component as due to an unresolved nuclear outflow. The narrower component velocity field shows strong isovelocity twists relative to a rotation pattern, implying the presence of strong non-circular motions. The subtraction of a rotational model reveals that these twists are caused by outflowing gas in the inner ≈ 1 ′′ , and by inflows associated with two spiral arms at larger radii. We calculate an ionized gas mass outflow rate ofṀ out ≈ 0.16 M ⊙ yr −1 . We calculate the net gas mass flow rate across a series of concentric rings, obtaining a maximum mass inflow rate in ionized gas of ≈ 2.8 M ⊙ year −1 at 800 pc from the nucleus, which is two orders of magnitude larger than the accretion rate necessary to power this AGN. However, as the mass inflow rate decreases at smaller radii, most of the gas probably will not reach the AGN, but accumulate in the inner few hundred parsecs. This will create a reservoir of gas that can trigger the formation of new stars.

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“…We visualize the simulations using two softwares namely Visit (used to generate Figures 1, 2, and 3 in this paper; see https://wci.llnl.gov/codes/visit/) and the software SHAPE (Steffen et al 2011) for the other figures. SHAPE is capable of visualizing HDF data in a variety of forbidden emission lines making it an ideal tool for generating observation comparable images and PV diagrams.…”

Section: Visualization and Diagnostic Toolsmentioning

confidence: 99%

Hubble Space Telescope scale 3D simulations of MHD disc winds: a rotating two-component jet structure

Staff

Koning

Ouyed

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We present the results of large scale, three-dimensional magneto-hydrodynamics simulations of disc-winds for different initial magnetic field configurations. The jets are followed from the source to 90 AU scale, which covers several pixels of HST images of nearby protostellar jets. Our simulations show that jets are heated along their length by many shocks. We compute the emission lines that are produced, and find excellent agreement with observations. The jet width is found to be between 20 and 30 AU while the maximum velocities perpendicular to the jet is found to be up to above 100km/s. The initially less open magnetic field configuration simulations results in a wider, two-component jet; a cylindrically shaped outer jet surrounding a narrow and much faster, inner jet. These simulations preserve the underlying Keplerian rotation profile of the inner jet to large distances from the source. However, for the initially most open magnetic field configuration the kink mode creates a narrow corkscrewlike jet without a clear Keplerian rotation profile and even regions where we observe rotation opposite to the disc (counter-rotating). The RW Aur jet is narrow, indicating that the disc field in that case is very open meaning the jet can contain a counterrotating component that we suggests explains why observations of rotation in this jet has given confusing results. Thus magnetized disc winds from underlying Keplerian discs can develop rotation profiles far down the jet that are not Keplerian.

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Shape: A 3D Modeling Tool for Astrophysics

Cited by 197 publications

References 25 publications

Space reconstruction of the morphology and kinematics of axisymmetric radio sources

Space reconstruction of the morphology and kinematics of axisymmetric radio sources

Gas inflows towards the nucleus of the Seyfert 2 galaxy NGC 1667

Hubble Space Telescope scale 3D simulations of MHD disc winds: a rotating two-component jet structure

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