scholarly journals MODELING JET INTERACTIONS WITH THE AMBIENT MEDIUM

2013 ◽  
Vol 53 (A) ◽  
pp. 683-686
Author(s):  
J. H. Beall ◽  
J. Guillory ◽  
D. V. Rose ◽  
Michael T. Wolff
Keyword(s):  
Large Scale ◽  
Ambient Medium ◽  
Time Dependent ◽  
Complex Structures ◽  
Relativistic Hydrodynamic ◽  
Astrophysical Jets ◽  
Hydrodynamic Simulations ◽  
Central Engine ◽  
Interstellar Material ◽  
Jet Interactions

Recent high-resolution (see, e.g., [13]) observations of astrophysical jets reveal complex structures apparently caused by ejecta from the central engine as the ejecta interact with the surrounding interstellar material. These observations include time-lapsed “movies” of both AGN and microquasars jets which also show that the jet phenomena are highly time-dependent. Such observations can be used to inform models of the jet–ambient-medium interactions. Based on an analysis of these data, we posit that a significant part of the observed phenomena come from the interaction of the ejecta with prior ejecta as well as interstellar material. In this view, astrophysical jets interact with the ambient medium through which they propagate, entraining and accelerating it. We show some elements of the modeling of these jets in this paper, including energy loss and heating via plasma processes, and large scale hydrodynamic and relativistic hydrodynamic simulations.

scholarly journals Large-scale Hydrodynamic Simulations of Astrophysical Jets

2018 ◽  
Author(s):  
James H. Beall ◽  
Kevin Lind ◽  
Pieter Meintjes ◽  
Dave Rose ◽  
Michael T. Wolff ◽  
...  
Keyword(s):  
Large Scale ◽  
Astrophysical Jets ◽  
Hydrodynamic Simulations

Simulations of the W50-SS433 system

2018 ◽  
Vol 14 (S342) ◽  
pp. 257-259
Author(s):  
Dimitrios Millas ◽  
Oliver Porth ◽  
Rony Keppens
Keyword(s):  
Radiative Transfer ◽  
Supernova Remnant ◽  
Relativistic Hydrodynamic ◽  
Astrophysical Jets ◽  
Hydrodynamic Simulations ◽  
X Ray ◽  
System A ◽  
The Universe

AbstractSupernovae and astrophysical jets are two of the most energetic and intriguing objects in the universe. We examine an interesting scenario that involves the interaction of these two extreme phenomena, motivated by observations of the W50-SS433 system: a jet launched from the microquasar SS433 (an X-ray binary) located inside a supernova remnant, W50. These observations revealed a unique morphology of the remnant, attributed to the presence of the jet. We performed full 3D relativistic hydrodynamic simulations to better capture the interaction between the remnant and the jet and post-processed the data with a radiative transfer code to create emission maps.

scholarly journals Bent It Like FRs: Extended Radio AGN in the COSMOS Field and Their Large-Scale Environment

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 93
Author(s):  
Eleni Vardoulaki ◽  
Franco Vazza ◽  
Eric F. Jiménez-Andrade ◽  
Ghassem Gozaliasl ◽  
Alexis Finoguenov ◽  
...  
Keyword(s):  
Large Scale ◽  
Ambient Medium ◽  
Adaptive Mesh ◽  
Radio Structure ◽  
X Ray ◽  
Galaxy Groups ◽  
Extended Radio ◽  
Wide Range ◽  
Jet Interactions ◽  
Host Properties

A fascinating topic in radio astronomy is how to associate the complexity of observed radio structures with their environment in order to understand their interplay and the reason for the plethora of radio structures found in surveys. In this project, we explore the distortion of the radio structure of Fanaroff–Riley (FR)-type radio sources in the VLA-COSMOS Large Project at 3 GHz and relate it to their large-scale environment. We quantify the distortion by using the angle formed between the jets/lobes of two-sided FRs, namely bent angle (BA). Our sample includes 108 objects in the redshift range 0.08<z<3, which we cross-correlate to a wide range of large-scale environments (X-ray galaxy groups, density fields, and cosmic web probes) in the COSMOS field. The median BA of FRs in COSMOS at zmed∼0.9 is 167.5−37.5+11.5 degrees. We do not find significant correlations between BA and large-scale environments within COSMOS covering scales from a few kpc to several hundred Mpc, nor between BA and host properties. Finally, we compare our observational data to magnetohydrodynamical (MHD) adaptive-mesh simulations ENZO-MHD of two FR sources at z = 0.5 and at z = 1. Although the scatter in BA of the observed data is large, we see an agreement between observations and simulations in the bent angles of FRs, following a mild redshift evolution with BA. We conclude that, for a given object, the dominant mechanism affecting the radio structures of FRs could be the evolution of the ambient medium, where higher densities of the intergalactic medium at lower redshifts as probed by our study allow more space for jet interactions.

scholarly journals Large-Scale Hydrodynamic Simulations of Astrophysical Jets

2020 ◽  
Author(s):  
James H. Beall ◽  
Kevin Lind ◽  
D.V. Rose ◽  
Michael T._Wolff ◽  
Izak van_der_Westhuizen ◽  
...  
Keyword(s):  
Large Scale ◽  
Astrophysical Jets ◽  
Hydrodynamic Simulations

scholarly journals FROM GALACTIC TO EXTRAGALACTIC JETS: A REVIEW

2013 ◽  
Vol 53 (A) ◽  
pp. 671-676
Author(s):  
James H. Beall
Keyword(s):  
Ambient Medium ◽  
Initial Energy ◽  
Electromagnetic Spectrum ◽  
Astronomical Unit ◽  
Complex Structures ◽  
Astrophysical Jets ◽  
X Ray ◽  
Extragalactic Jets ◽  
First Results ◽  
Centaurus A

An analysis of the data that have recently become available from observing campaigns, including VLA, VLBA, and satellite instruments, shows some remarkable similarities and significant differences in the data from some epochs of galactic microquasars, including GRS 1915+105, the concurrent radio and X-ray data [3] on Centaurus A (NGC 5128), 3C120 [35], and 3C454.3 as reported by Bonning et al. [16], which showed the first results from the Fermi Space Telescope for the concurrent variability at optical, UV, IR, and g-ray variability of that source. In combination with observations from microquasars and quasars from the MOJAVE Collaboration [32], these data provide time-dependent evolutions of radio data at mas (i.e., parsec for AGNs, and Astronomical Unit scales for microquasars). These sources all show a remarkable richness of patterns of variability for astrophysical jets across the entire electromagnetic spectrum. It is likely that these patterns of variability arise from the complex structures through which the jets propagate, but it is also possible that the jets constitution, initial energy, and collimation have significant observational consequences. On the other hand, Ulrich et al. [42] suggest that this picture is complicated for radio-quiet AGN by the presence of significant emission from accretion disks in those sources. Consistent with the jet-ambient-medium hypothesis, the observed concurrent radio and X-ray variability of Centaurus A [3] could have been caused by the launch of a jet element from Cen A’s central source and that jet’s interaction with the interstellar medium in the core region of that galaxy.

scholarly journals Multiscale Modeling of Astrophysical Jets

2014 ◽  
Vol 1 (1) ◽  
pp. 274-277
Author(s):  
James H. Beall ◽  
John Guillory ◽  
David V. Rose ◽  
Michael T. Wolff
Keyword(s):  
Momentum Transfer ◽  
Large Scale ◽  
Energy Deposition ◽  
Galactic Center ◽  
Ambient Medium ◽  
Astrophysical Jets ◽  
Transfer Rates ◽  
Particle In Cell ◽  
Multi Scale ◽  
Astrophysical Jet

<p>We are developing the capability for a multi-scale code to model the energy deposition rate and momentum transfer rate of an astrophysical jet which generates strong plasma turbulence in its interaction with the ambient medium through which it propagates. We start with a highly parallelized version of the VH-1 Hydrodynamics Code (Coella and Wood 1984, and Saxton et al., 2005). We are also considering the PLUTO code (Mignone et al. 2007) to model the jet in the magnetohydrodynamic (MHD) and relativistic, magnetohydrodynamic (RMHD) regimes. Particle-in-Cell approaches are also being used to benchmark a wave-population models of the two-stream instability and associated plasma processes in order to determine energy deposition and momentum transfer rates for these modes of jet-ambient medium interactions. We show some elements of the modeling of these jets in this paper, including energy loss and heating via plasma processes, and large scale hydrodynamic and relativistic hydrodynamic simulations. A preliminary simulation of a jet from the galactic center region is used to lend credence to the jet as the source of the so-called the Fermi Bubble (see, e.g., Su, M. &amp; Finkbeiner, D. P., 2012)</p><p>*It is with great sorrow that we acknowledge the loss of our colleague and friend of more than thirty years, Dr. John Ural Guillory, to his battle with cancer.</p>

Benchmark of Simplified Time-Dependent Density Functional Theory for UV-Vis Spectral Properties of Porphyrinoids

2019 ◽  
Author(s):  
Kamal Batra ◽  
Stefan Zahn ◽  
Thomas Heine
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Large Scale ◽  
Absolute Error ◽  
Time Dependent ◽  
Basis Set ◽  
Basis Sets ◽  
Functional Theory ◽  
Framework Materials ◽  
Dependent Density

<p>We thoroughly benchmark time-dependent density- functional theory for the predictive calculation of UV/Vis spectra of porphyrin derivatives. With the aim to provide an approach that is computationally feasible for large-scale applications such as biological systems or molecular framework materials, albeit performing with high accuracy for the Q-bands, we compare the results given by various computational protocols, including basis sets, density-functionals (including gradient corrected local functionals, hybrids, double hybrids and range-separated functionals), and various variants of time-dependent density-functional theory, including the simplified Tamm-Dancoff approximation. An excellent choice for these calculations is the range-separated functional CAM-B3LYP in combination with the simplified Tamm-Dancoff approximation and a basis set of double-ζ quality def2-SVP (mean absolute error [MAE] of ~0.05 eV). This is not surpassed by more expensive approaches, not even by double hybrid functionals, and solely systematic excitation energy scaling slightly improves the results (MAE ~0.04 eV). </p>

In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects

2004 ◽  
Vol 261-263 ◽  
pp. 1097-1102 ◽  
Author(s):  
Jian Liu ◽  
Xia Ting Feng ◽  
Xiu Li Ding ◽  
Huo Ming Zhou
Keyword(s):  
Rock Mass ◽  
Creep Behavior ◽  
Large Scale ◽  
Time Dependent ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.

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