Propagation and Dynamics of Relativistic Jets

Mizuta, Akira; Yamada, Shoichi; Takabe, H.

doi:10.1086/382779

Cited by 47 publications

(78 citation statements)

References 59 publications

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“…The jet is well collimated both inside of the progenitor and as it travels through the ISM. The bow shock develops close to the head of the jet and rises the pressure and the temperature of the envelope region it sweeps up (in agreement with the findings of Mizuta et al 2004). It takes about 3.2 s for the jet to cross the progenitor, hence, the average propagation velocity is ∼ 0.63c.…”

Section: Dynamicssupporting

confidence: 87%

“…In the later case, the occurrence of recollimation shocks much closer to the injection nozzle prevents the development a freely expanding, unshocked jet extending so far away as in the models of this work. Indeed, such internal, recollimation shocks are the responsible of the confinement of the jet (Komissarov & Falle 1997Mizuta et al 2004Mizuta et al , 2006Mimica et al 2008). Nonetheless, the head propagation speed is very similar in Mizuta et al (2006) as it is found here and, hence, also the crossing time of the progenitor by the jet.…”

Section: Acceleration To High Lorentz Factorsupporting

confidence: 76%

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Angular Energy Distribution of Collapsar-Jets

Mizuta

Aloy

2009

ApJ

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122

119

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Collapsars are fast-spinning, massive stars, whose core collapse liberates an energy, that can be channeled in the form of ultrarelativistic jets. These jets transport the energy from the collapsed core to large distances, where it is dissipated in the form of long-duration gamma-ray bursts. In this paper we study the dynamics of ultrarelativistic jets produced in collapsars. Also we extrapolate our results to infer the angular energy distribution of the produced outflows in the afterglow phase. Our main focus is to look for global energetical properties which can be imprinted by the different structure of different progenitor stars. Thus, we employ a number of pre-supernova, stellar models (with distinct masses and metallicities), and inject in all of them jets with fixed initial conditions. We assume that at the injection nozzle, the jet is mildly relativistic (Lorentz factor ∼ 5), has a finite half-opening angle (5 • ), and carries a power of 10 51 erg s −1 . In all cases, well collimated jets propagate through the progenitor, blowing a high pressure and high temperature cocoon. These jets arrive intact to the stellar surface and break out of it. A large Lorentz factor region Γ > ∼ 100 develops well before the jet reaches the surface of the star, in the unshocked part of the beam, located between the injection nozzle and the first recollimation shock. These high values of Γ are possible because the finite opening angle of the jet allows for free expansion towards the radial direction. We find a strong correlation between the angular energy distribution of the jet, after its eruption from the progenitor surface, and the mass of the progenitors. The angular energy distribution of the jets from light progenitor models is steeper than that of the jets injected in more massive progenitor stars. This trend is also imprinted in the angular distribution of isotropic equivalent energy.

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Section: Dynamicssupporting

confidence: 87%

Section: Acceleration To High Lorentz Factorsupporting

confidence: 76%

Angular Energy Distribution of Collapsar-Jets

Mizuta

Aloy

2009

ApJ

Self Cite

122

119

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“…The strong terminal shocks at the hot spots are unlikely to be moving with high bulk Lorentz factors, but moderately relativistic motions (À blk a few) are permitted by hydrodynamic simulations (e.g., Aloy et al 1999). We note that such simulations repeatedly reveal a complex hot spot morphology, especially at the late stages of the jet evolution (e.g., Martí et al 1997;Mizuta et al 2004). Finally, the main-axis expansion of the radio lobe is thought to be subrelativistic; À blk ' 1.…”

Section: Introductionmentioning

confidence: 81%

X‐Ray Emission Properties of Large‐Scale Jets, Hot Spots, and Lobes in Active Galactic Nuclei

Kataoka

Stawarz

2005

ApJ

237

269

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We examine a systematic comparison of jet knots, hot spots, and radio lobes recently observed with Chandra and ASCA. This report discusses the origin of their X-ray emissions and investigates the dynamics of the jets. The data were compiled at well-sampled radio (5 GHz) and X-ray (1 keV ) frequencies for more than 40 radio galaxies. We examine three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC), and external Compton ( EC) on cosmic microwave background (CMB) photons. For the SYN sources-mostly jet knots in nearby low-luminosity radio galaxies-X-ray photons are produced by ultrarelativistic electrons with energies 10-100 TeV that must be accelerated in situ. For the other objects, conservatively classified as SSC or EC sources, a simple formulation of calculating the ''expected'' X-ray fluxes under an equipartition hypothesis is presented. We confirm that the observed X-ray fluxes are close to the expected ones for nonrelativistic emitting plasma velocities in the case of radio lobes and the majority of hot spots, whereas a considerable fraction of jet knots are too bright in X-rays to be explained in this way. We examine two possibilities to account for the discrepancy in a framework of the inverse Compton model: (1) the magnetic field is much smaller than the equipartition value, and (2) the jets are highly relativistic on kiloparsec and megaparsec scales. We conclude that if the inverse Compton model is the case, the X-ray-bright jet knots are most likely far from the minimum-power condition. We also briefly discuss the other possibility, namely, that the observed X-ray emission from all the jet knots is synchrotron in origin.

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“…The 2D special relativistic hydrodynamic equations are solved, using our relativistic hydrodynamic code based on Godunov-type scheme (Mizuta et al, 2004(Mizuta et al, , 2006). An ideal equation of state p = (γ − 1)ρ is also solved to close the equations, where p is pressure, the constant γ (= 4/3) is specific heat ratio, ρ is rest mass density, and is specific internal energy.…”

Section: Modelmentioning

confidence: 99%

Outflow Propagation in Collapsars: Collimated Jets and Expanding Outflows

Mizuta¹,

Yamasaki²,

Nagataki³

et al. 2006

High Energy Density Laboratory Astrophysics

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We investigate the outflow propagation in the collapsar in the context of gamma-ray bursts (GRBs) with 2D relativistic hydrodynamic simulations. We vary the specific internal energy and bulk Lorentz factor of the injected outflow from non-relativistic regime to relativistic one, fixing the power of the outflow to be 10 51 erg s −1 . We observed the collimated outflow, when the Lorentz factor of the injected outflow is roughly greater than 2. To the contrary, when the velocity of the injected outflow is slower, the expanding outflow is observed. The transition from collimated jet to expanding outflow continuously occurs by decreasing the injected velocity. Different features of the dynamics of the outflows would cause the difference between the GRBs and similar phenomena, such as, X-ray flashes.

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Propagation and Dynamics of Relativistic Jets

Cited by 47 publications

References 59 publications

Angular Energy Distribution of Collapsar-Jets

Angular Energy Distribution of Collapsar-Jets

X‐Ray Emission Properties of Large‐Scale Jets, Hot Spots, and Lobes in Active Galactic Nuclei

Outflow Propagation in Collapsars: Collimated Jets and Expanding Outflows

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