scholarly journals Observations and spectral modelling of the narrow-lined Type Ic SN 2017ein

2021 ◽  
Vol 502 (3) ◽  
pp. 3829-3842
Author(s):  
J J Teffs ◽  
S J Prentice ◽  
P A Mazzali ◽  
C Ashall
Keyword(s):  
Monte Carlo ◽  
Radiation Transport ◽  
Emission Feature ◽  
High Mass ◽  
Single Star ◽  
Transport Code ◽  
Consistent Model ◽  
The Face ◽  
Low Mass ◽  
Compact Cluster

ABSTRACT SN 2017ein is a narrow-lined Type Ic SN that was found to share a location with a point-like source in the face on spiral galaxy NGC 3938 in pre-supernova images, making SN 2017ein the first credible detection of a Type Ic progenitor. Results in the literature suggest that this point-like source is likely a massive progenitor of 60–80 M⊙, depending on if the source is a binary, a single star, or a compact cluster. Using new photometric and spectral data collected for 200 d, including several nebular spectra, we generate a consistent model covering the photospheric and nebular phase using a Monte Carlo radiation transport code. Photospheric phase modelling finds an ejected mass 1.2–2.0 M⊙ with an Ek of ∼(0.9 ± 0.2) × 1051 erg, with approximately 1 M⊙ of material below 5000 km s−1 found from the nebular spectra. Both photospheric and nebular phase modelling suggests a 56Ni mass of 0.08–0.1 M⊙. Modelling the [O i] emission feature in the nebular spectra suggests that the innermost ejecta are asymmetric. The modelling results favour a low-mass progenitor of 16–20 M⊙, which is in disagreement with the pre-supernova derived high-mass progenitor. This contradiction is likely due to the pre-supernova source not representing the actual progenitor.

Integrating Circuit Level Simulation and Monte-Carlo Radiation Transport Code for Single Event Upset Analysis in SEU Hardened Circuitry

2008 ◽  
Vol 55 (6) ◽  
pp. 2886-2894 ◽  
Author(s):  
Kevin M. Warren ◽  
Andrew L. Sternberg ◽  
Robert A. Weller ◽  
Mark P. Baze ◽  
Lloyd W. Massengill ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Radiation Transport ◽  
Single Event Upset ◽  
Single Event ◽  
Transport Code

scholarly journals No missing photons for reionization: moderate ionizing photon escape fractions from the FIRE-2 simulations

2020 ◽  
Vol 498 (2) ◽  
pp. 2001-2017 ◽  
Author(s):  
Xiangcheng Ma ◽  
Eliot Quataert ◽  
Andrew Wetzel ◽  
Philip F Hopkins ◽  
Claude-André Faucher-Giguère ◽  
...  
Keyword(s):  
Large Fraction ◽  
High Mass ◽  
Population Synthesis ◽  
Single Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Sample Average ◽  
Dense Shell ◽  
Low Mass ◽  
Dust Attenuation

ABSTRACT We present the escape fraction of hydrogen ionizing photons (fesc) from a sample of 34 high-resolution cosmological zoom-in simulations of galaxies at z ≥ 5 in the Feedback in Realistic Environments project, post-processed with a Monte Carlo radiative transfer code for ionizing radiation. Our sample consists of 8500 haloes in Mvir ∼ 108–$10^{12}\, M_{\odot }$ (M* ∼ 104–$10^{10}\, M_{\odot }$) at z = 5–12. We find the sample average 〈fesc〉increases with halo mass for Mvir ∼ 108–$10^{9.5}\, M_{\odot }$, becomes nearly constant for 109.5–$10^{11}\, M_{\odot }$, and decreases at ${\gtrsim}10^{11}\, M_{\odot }$. Equivalently, 〈fesc〉 increases with stellar mass up to $M_{\ast }\sim 10^8\, M_{\odot }$ and decreases at higher masses. Even applying single-star stellar population synthesis models, we find a moderate 〈fesc〉 ∼ 0.2 for galaxies at $M_{\ast }\sim 10^8\, M_{\odot }$. Nearly half of the escaped ionizing photons come from stars 1–3 Myr old and the rest from stars 3–10 Myr old. Binaries only have a modest effect, boosting 〈fesc〉 by ∼25–35 per cent and the number of escaped photons by 60–80 per cent. Most leaked ionizing photons are from vigorously star-forming regions that usually contain a feedback-driven kpc-scale superbubble surrounded by a dense shell. The shell is forming stars while accelerated, so new stars formed earlier in the shell are already inside the shell. Young stars in the bubble and near the edge of the shell can fully ionize some low-column-density paths pre-cleared by feedback, allowing a large fraction of their ionizing photons to escape. The decrease of 〈fesc〉 at the high-mass end is due to dust attenuation, while at the low-mass end, 〈fesc〉 decreases owing to inefficient star formation and hence feedback. At fixed mass, 〈fesc〉 tends to increase with redshift. Although the absolute 〈fesc〉does not fully converge with resolution in our simulations, the mass- and redshift-dependence of 〈fesc〉 is likely robust. Our simulations produce sufficient ionizing photons for cosmic reionization.

Acceleration of a Monte Carlo radiation transport code

1996 ◽  
Author(s):  
Reuben D. Hochstedler ◽  
L. Montgomery Smith
Keyword(s):  
Monte Carlo ◽  
Radiation Transport ◽  
Transport Code

Comparing Id and Haskell in a Monte Carlo photon transport code

1995 ◽  
Vol 5 (3) ◽  
pp. 283-316 ◽  
Author(s):  
Jeffrey Hammes ◽  
Olaf Lubeck ◽  
Wim Böhm
Keyword(s):  
Monte Carlo ◽  
Data Structures ◽  
Radiation Transport ◽  
Large Problem ◽  
Good Test ◽  
Transport Code ◽  
Recursive Data Structures ◽  
Recursive Data ◽  
Monte Carlo Transport ◽  
Simulation Exercises

AbstractIn this paper we present functional Id and Haskell versions of a large Monte Carlo radiation transport code, and compare the two languages with respect to their expressiveness. Monte Carlo transport simulation exercises such abilities as parsing, input/output, recursive data structures and traditional number crunching, which makes it a good test problem for languages and compilers. Using some code examples, we compare the programming styles encouraged by the two languages. In particular, we discuss the effect of laziness on programming style. We point out that resource management problems currently prevent running realistically large problem sizes in the functional versions of the code.

scholarly journals Virtual Igor: an analytical phantom for the simulation of the Saint Petersburg brick phantom in arbitrary layouts in MCNP

2021 ◽  
Author(s):  
Oliver Meisenberg
Keyword(s):  
Monte Carlo ◽  
User Interfaces ◽  
Radiation Transport ◽  
Computer Code ◽  
Graphical User Interfaces ◽  
Whole Body ◽  
Saint Petersburg ◽  
Transport Code ◽  
Drill Holes ◽  
Computational Phantoms

AbstractA computer code called Virtual Igor is presented. The code generates an analytical representation of the Saint Petersburg brick phantom family (Igor, Olga, Irina), which is frequently used for the calibration of whole-body counters, in arbitrary user-defined layouts for the use in the Monte-Carlo radiation transport code MCNP. The computer code reads a file in the ldraw format, which can easily be produced by simple freeware software with graphical user interfaces and which contains the types and coordinates of the bricks. Ldraw files with the canonical layouts of the brick phantom are provided with Virtual Igor. The code determines the positions of (2.75 cm)3 segments of the bricks, where 2.75 cm is the smallest length in the layout and, therefore, represents the spacing of the segment lattice. Each segment contains the exact geometry of the respective part of the brick, using cuboid and cylindrical surfaces. The user can define which rod source drill holes of which bricks contain the rod-type radionuclide sources. The method facilitates the comparison of different layouts of the Saint Petersburg brick phantom with each other and with anthropomorphic computational phantoms.

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