scholarly journals The radiative transfer for polarized radiation at second order in cosmological perturbations

2009 ◽  
Vol 41 (11) ◽  
pp. 2587-2595 ◽  
Author(s):  
Cyril Pitrou
Keyword(s):  
Radiative Transfer ◽  
Second Order ◽  
Cosmological Perturbations ◽  
Polarized Radiation

Second-order scattering approximation of pulse vector radiative transfer equation

2003 ◽  
Vol 216 (4-6) ◽  
pp. 273-287
Author(s):  
Sermsak Jaruwatanadilok ◽  
Akira Ishimaru ◽  
Yasuo Kuga
Keyword(s):  
Radiative Transfer ◽  
Transfer Equation ◽  
Radiative Transfer Equation ◽  
Second Order ◽  
Scattering Approximation

scholarly journals Dynamics of cosmological perturbations at first and second order

2018 ◽  
Vol 98 (10) ◽  
Author(s):  
Claes Uggla ◽  
John Wainwright
Keyword(s):  
Second Order ◽  
Cosmological Perturbations

A New Stabilized Finite Element Formulation for Solving Radiative Transfer Equation

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
L. Zhang ◽  
J. M. Zhao ◽  
L. H. Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Radiative Transfer ◽  
Transfer Equation ◽  
Radiative Transfer Equation ◽  
Second Order ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Stabilized Finite Element ◽  
Element Method

A new stabilized finite element formulation for solving radiative transfer equation is presented. It owns the salient feature of least-squares finite element method (LSFEM), i.e., free of the tuning parameter that appears in the streamline upwind/Petrov–Galerkin (SUPG) finite element method. The new finite element formulation is based on a second-order form of the radiative transfer equation. The second-order term will provide essential diffusion as the artificial diffusion introduced in traditional stabilized schemes to ensure stability. The performance of the new method was evaluated using challenging test cases featuring strong medium inhomogeneity and large gradient of radiative intensity field. It is demonstrated to be computationally efficient and capable of solving radiative heat transfer in strongly inhomogeneous media with even better accuracy than the LSFEM, and hence a promising alternative finite element formulation for solving complex radiative transfer problems.

G-INFLATION: INFLATION WITH THE MOST GENERAL SECOND-ORDER FIELD EQUATIONS

2012 ◽  
Vol 10 ◽  
pp. 77-84
Author(s):  
TSUTOMU KOBAYASHI ◽  
MASAHIDE YAMAGUCHI ◽  
JUN'ICHI YOKOYAMA
Keyword(s):  
Power Spectra ◽  
Second Order ◽  
Stability Criteria ◽  
Cosmological Perturbations ◽  
Field Equations ◽  
Special Cases ◽  
Single Field ◽  
The Stability

In this talk, we have discussed generalized Galileons as a framework to develop the most general single-field inflation models ever, (Generalized) G-inflation, containing previous examples such as k-inflation, extended inflation, and new Higgs inflation as special cases. We have also investigated the background and perturbation evolution in this model, calculating the most general quadratic actions for tensor and scalar cosmological perturbations to give the stability criteria and the power spectra of primordial fluctuations.

scholarly journals Spectropolarimetry of SN 2011dh in M51: geometric insights on a Type IIb supernova progenitor and explosion

2015 ◽  
Vol 453 (4) ◽  
pp. 4467-4484 ◽  
Author(s):  
Jon C. Mauerhan ◽  
G. Grant Williams ◽  
Douglas C. Leonard ◽  
Paul S. Smith ◽  
Alexei V. Filippenko ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Position Angle ◽  
Oblique Shock ◽  
Time Variable ◽  
Core Collapse ◽  
Circumstellar Material ◽  
The Core ◽  
Radioactive Heating ◽  
The Continuum ◽  
Polarized Radiation

Abstract We present seven epochs of spectropolarimetry of the Type IIb supernova (SN IIb) 2011dh in M51, spanning 86 d of its evolution. The first epoch was obtained 9 d after the explosion, when the photosphere was still in the depleted hydrogen layer of the stripped-envelope progenitor. Continuum polarization is securely detected at the level of P ≈ 0.5 per cent through day 14 and appears to diminish by day 30, which is different from the prevailing trends suggested by studies of other core-collapse SNe. Time-variable modulations in P and position angle are detected across P-Cygni line features. H α and He i polarization peak after 30 d and exhibit position angles roughly aligned with the earlier continuum, while O i and Ca ii appear to be geometrically distinct. We discuss several possibilities to explain the evolution of the continuum and line polarization, including the potential effects of a tidally deformed progenitor star, aspherical radioactive heating by fast-rising plumes of 56Ni from the core, oblique shock breakout, or scattering by circumstellar material. While these possibilities are plausible and guided by theoretical expectations, they are not unique solutions to the data. The construction of more detailed hydrodynamic and radiative-transfer models that incorporate complex aspherical geometries will be required to further elucidate the nature of the polarized radiation from SN 2011dh and other SNe IIb.

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