3D Astrophysics Newsletter

Models of an xpanding bipolar radio nova.

Models of an expanding bipolar radio nova.

2.3 Today´s new entry:

The Distance to Nova V959 Mon from VLA Imaging

J. D. Linford, V. A. R. M. Ribeiro, L. Chomiuk, T. Nelson, J. L. Sokoloski, M. P. Rupen, K. Mukai, T. J. O’Brien, A. J. Mioduszewski, J. Weston

Determining reliable distances to classical novae is a challenging but crucial step in deriving their ejected masses and explosion energetics. Here we combine radio expansion measurements from the Karl G. Jansky Very Large Array with velocities derived from optical spectra to estimate an expansion parallax for nova V959 Mon, the first nova discovered through its gamma-ray emission. We spatially resolve the nova at frequencies of 4.5-36.5 GHz in nine different imaging epochs. The first five epochs cover the expansion of the ejecta from 2012 October to 2013 January, while the final four epochs span 2014 February to 2014 May. These observations correspond to days 126 through 199 and days 615 through 703 after the first detection of the nova. The images clearly show a non-spherical ejecta geometry. Utilizing ejecta velocities derived from 3D modelling of optical spectroscopy, the radio expansion implies a distance between 0.9 +/- 0.2 and 2.2 +/- 0.4 kpc, with a most probable distance of 1.4 +/- 0.4 kpc. This distance implies a gamma-ray luminosity much less than the prototype gamma-ray-detected nova, V407 Cyg, possibly due to the lack of a red giant companion in the V959 Mon system. V959 Mon also has a much lower gamma-ray luminosity than other classical novae detected in gamma-rays to date, indicating a range of at least a factor of 10 in the gamma-ray luminosities for these explosions.

Journal: Astrophysical Journal
Comments: 11 pages, 8 figures, 3 tables
URL of preprint: http://adsabs.harvard.edu/abs/2015arXiv150303899L
Submitted by: Valerio Ribeiro

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Postdoc position on “3-D View of high-mass star formation at 10-103AU scales”

There is a postdoc position available at INAF-Osservatorio Astrofisico di Arcetri, Florence, Italy, on the subject “3-D View of high-mass star formation at 10-103  AU scales”. For more information have a look at link to the full announcement.

3D Astrophysics Newsletter

3D simulation of a nova explosion.

3D simulation of a nova explosion.

2.2 Today´s new entry:

Simulations of the symbiotic recurrent nova V407 Cyg. I. Accretion and shock evolutions

Kuo-Chuan Pan, Paul Ricker, Ronald Taam

The shock interaction and evolution of nova ejecta with a wind from a red giant star in a symbiotic binary system are investigated via three-dimensional hydrodynamics simulations. We specifically model the March 2010 outburst of the symbiotic recurrent nova V407~Cygni from the quiescent phase to its eruption phase. The circumstellar density enhancement due to wind-white dwarf interaction is studied in detail. It is found that the density-enhancement efficiency depends on the ratio of the orbital speed to the red giant wind speed. Unlike another recurrent nova, RS~Ophiuchi, we do not observe a strong disk-like density enhancement, but instead observe an aspherical density distribution with ∼20% higher density in the equatorial plane than at the poles. To model the 2010 outburst, we consider several physical parameters, including the red giant mass loss rate, nova eruption energy, and ejecta mass. A detailed study of the shock interaction and evolution reveals that the interaction of shocks with the red giant wind generates strong Rayleigh-Taylor instabilities. In addition, the presence of the companion and circumstellar density enhancement greatly alter the shock evolution during the nova phase. The ejecta speed after sweeping out most of the circumstellar medium decreases to ∼100−300 km-s−1, depending on model, which is consistent with the observed extended redward emission in [N~II] lines in April 2011.

Journal: The Astrophysical Journal, in press
URL of preprint: http://arxiv.org/abs/1503.06181
Submitted by: Kuo-Chuan Pan
Email: kuo-chuan.pan@unibas.ch

3D reconstructions with meshes

Fabric is made of a mesh of many aligned threads. Although basically a 2D structure, it can be turned into complex 3D objects.

Fabric is made of a mesh of many aligned threads. Although basically a 2D structure, it can be turned into complex 3D objects.

The fabric that makes up most of our clothes is made up of fine threads that are interwoven and form a mesh structure. We all know that, of course. Bare with me, I will get to what it has to do with 3D astrophysics.

Usually there are two perpendicular sets of threads that interweave and form a two-dimensional sheet. If we number the threads sequentially and separately for each of the two sets, then we can identify the position of a flower on the fabric by providing the numbers of the threads at the nearest intersection point.

A 2D mesh can be molded into a complex 3D nebula.

A 2D mesh can be molded into a complex 3D nebula.

The mechanical flexibility of fabric allows it to be distorted and reshaped into almnost any three-dimensional surface structure that you can imagine. That is why we can wrap ourselves into clothes made from such fabric although we are fully three-dimensional beings.

mesh_render

After assigning physical properties to the volumes enclosed by the meshes, the nebula can be rendered as a image or other form of data.

Now, the cool thing is that however we change the 3-D shape of the sheet, the 2-D coordinates of the flower have not changed if we use the number of threads as coordinates. It is a bit like Einsteins description of the distortion of space-time by gravitational mass. These 2-D coordinate description of a fabric and its deformability into 3-D is a key property of such mesh structures that allows the incredible realism of modern 3-D animation to be computed on a reasonable timescale. Is the idea of using meshes for 3-D modeling at all useful or already being used in astrophysics?  Continue reading

3D Astrophysics Newsletter

3D printed hydrodynamics simulation of the interacting wind region in Eta Carinae. See the 3D interactive features in the preprint PDF file.

3D printed hydrodynamic simulation of the interacting wind region in Eta Carinae. See the 3D interactive features in the preprint PDF file.

2.1 Today’s new entry:

3D Printing Meets Computational Astrophysics: Deciphering the Structure of Eta Carinae’s Inner Colliding Winds

T.I. Madura, N. Clementel, T.R. Gull, C.J.H. Kruip, J.-P. Paardekooper

Abstract: We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (>120 M_Sun), highly eccentric (e ~ 0.9) binary star system Eta Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF journal publication and the benefits of using 3D visualization and 3D printing as tools to analyze data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics (SPH) simulations of Eta Carinae’s inner (r ~ 110 au) wind-wind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown ‘finger-like’ structures at orbital phases shortly after periastron (phi ~ 1.045) that protrude radially outward from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise at the interface between the radiatively-cooled layer of dense post-shock primary-star wind and the fast (3000 km/s), adiabatic post-shock companion-star wind. The success of our work and easy identification of previously unrecognized physical features highlight the important role 3D printing and interactive graphics can play in the visualization and understanding of complex 3D time-dependent numerical simulations of astrophysical phenomena.

Journal: Monthly Notices of the Royal Astronomical Society, in press
URL of preprint: http://arxiv.org/abs/1503.00716 (38 MB !)
Comments: To view 3D interactive figures and movie, use Adobe PDF viewer.
Submitted by: Thomas Madura

3DA Newsletter

Edition 1: March 2015

This is the first edition of the newsletter on 3D Astrophysics. We provide a summary of the papers that have been submitted by the authors. Links to the abstracts and preprints or the published papers are provided.

We are looking forward to the next edition. In order to spread the word on your papers as soon as possible to this group of people with a special interest in 3D astrophysics, in addition to the bimonthly summaries, we publish each submission as a blog post shortly after receiving the abstract. See the title page of the 3DA newsletter for details and a link the submission page.

Wolfgang Steffen & Nico Koning
Editors

1.1 Obscuration-dependent evolution of Active Galactic Nuclei, J. Buchner, A. Georgakakis, K. Nandra, M. Brightman, Ma.-L. Menzel, Z. Liu, Li-T. Hsu, M. Salvato, C. Rangel, J. Aird, A. Merloni, N. Ross, The Astrophysical Journal, in press
URL of preprint: http://arxiv.org/abs/1501.02805
Abstract
Submitted by: Johannes Buchner

1.2 ALMA data suggest the presence of spiral structure in the inner wind of CW Leonis, L. Decin, A. M.S. Richards, D. Neufeld, W. Steffen, G. Melnick, R. Lombaert
Journal: Astronomy & Astrophysics, in press.
URL of preprint: http://adsabs.harvard.edu/abs/2015A%26A…574A…5D
Abstract
Submitted by: Leen Decin (University of Leuven, Belgium)

1.3. Galaxy Emission Line Classification Using Three-dimensional Line Ratio Diagrams, Vogt, F.P.A., Dopita, M.A., Kewley, L.J., Sutherland, R.S., Scharwächter, J., Basurah, H.M., Ali, A., Amer, M.A., The Astrophysical Journal, in press,
URL of preprint: http://arxiv.org/abs/1406.5186
Comments: Interactive 3D HTML model is here:
dx.doi.org/10.1088/0004-637X/793/2/127/data
Abstract
Submitted by: Frédéric Vogt

1.4 Spatially resolved kinematic observations of the planetary nebulae Hen 3-1333 and Hen 2-113, A. Danehkar, Q. Parker, MNRAS Letters,
URL of publication: http://dx.doi.org/10.1093/mnrasl/slv022
Submitted by: Ashkbiz Danehkar