Preparation and stability of W/O/W emulsions containing sucrose as weighting agent

Zhang, Jian; Reineccius, Gary A.

doi:10.1002/ffj.3269

Cited by 21 publications

(47 citation statements)

References 33 publications

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“…In case of δ > 1, a large δ value (δ = 16.6) is required to model the SED of knot-B1. This value is comparable with the derived variability Doppler factor of δ = 17 for pc-scale jet in Hovatta et al (2009), but is much larger than that reported by Liodakis et al (2017, δ = 3.7), and even larger than the core-jet value of δ = 7.4 ± 0.9 derived by SED fitting (Zhang et al 2014(Zhang et al , 2015. Therefore, Scenario I could not present a reasonable explanation for the SEDs of knots.…”

Section: Discussionsupporting

confidence: 70%

Leptonic or Hadronic Emission: The X-Ray Radiation Mechanism of Large-scale Jet Knots in 3C 273

Wang

Zhang

Sun

et al. 2020

ApJ

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A comprehensively theoretical analysis on the broadband spectral energy distributions (SEDs) of large-scale jet knots in 3C 273 is presented for revealing their X-ray radiation mechanism. We show that these SEDs cannot be explained with a single electron population model when the Doppler boosting effect is either considered or not. By adding a more energetic electron (the leptonic model) or proton (the hadronic model) population, the SEDs of all knots are well represented. In the leptonic model, the electron population that contributes the X-ray emission is more energetic than the one responsible for the radio-optical emission by almost two orders of magnitude; the derived equipartition magnetic field strengths (B eq ) are ∼ 0.1 mG. In the hadronic model, the protons with energy of ∼ 20 PeV are required to interpret the observed X-rays; the B eq values are several mG, larger than that in the leptonic model. Based on the fact that no resolved substructures are observed in these knots and the fast cooling-time of the high-energy electrons is difficult to explain the observed X-ray morphologies, we argue that two distinct electron populations accelerated in these knots are unreasonable and their X-ray emission would be attributed to the proton synchrotron radiation accelerated in these knots. In case of these knots have relativistic motion towards the observer, the super-Eddington issue of the hadronic model could be avoided. Multiwavelength polarimetry and the γ-ray observations with high resolution may be helpful to discriminate these models.In this scenario, the synchrotron, SSC, and IC/CMB radiations of a single electron population are used to reproduce the broadband SEDs of knots. The radiating electrons are assumed to have the number distribution as Equation (1). The minimum and maximum energies of electrons are taken as E e,min =1 MeV and E e,max =510 TeV, which are respectively corresponding to γ e ∼ 2 and γ e ∼ 10 9 , where γ e is the Lorenz factor of electrons. In case of the knots do not have the relativistic motions, i.e., δ = Γ = 1, the IC component would be dominated by the SSC process since the energy density of the synchrotron radiation photon field (U syn ) is higher than U ′ CMB . A magnetic field strength (B) lower than the equipartition value (B eq ) is also needed (e.g.

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Section: Discussionsupporting

confidence: 70%

Leptonic or Hadronic Emission: The X-Ray Radiation Mechanism of Large-scale Jet Knots in 3C 273

Wang

Zhang

Sun

et al. 2020

ApJ

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“…The bulk Lorentz factor of the emission region is Γ, and the beaming factor should be δ = 1/Γ(1−β cos θ), where θ is the viewing angle. The radiation electron distribution is taken as a broken power-law (Ghisellini et al 2009;Zhang et al 2014Zhang et al , 2015Chen et al 2012), and this distribution is characterized by an electron density parameter (N 0 ), a break energy (γ b ) , and two slope indices (p 1 and p 2 ) below and above the break energy in the energy range of γ e ∈ [γ min , γ max ]. The Klein-Nashina (KN) effect and the absorption of high energy γ-ray photons by extragalactic background light (Franceschini et al 2008) are also taken into account in our model calculations.…”

Section: Sed Modeling and Results For The Core And Knotsmentioning

confidence: 99%

“…As illustrated in Figure 2, the blue bump of the thermal emission from the accretion disk is prominent when the source is in a low state of γ-ray radiation. Following our previous work (Sun et al 2015;Zhang et al 2015), the standard accretion disk spectrum (Davis & Laor 2011) is used to explain this thermal emission. The fitting parameters include the inside (R in ) and outside radii (R out ) of the accretion disk, black hole mass (M BH ), Eddington ratio, and inclination to the line of sight i.…”

Section: The Core Regionmentioning

confidence: 99%

“…The broadband spectral energy distributions (SEDs) of both the radio-core and large-scale jet radiations for radioloud AGNs shows that they are non-thermal emission origin and show a bimodal feature (e.g., Sikora et al 1994;Ghisellini et al 2009;Zhang et al 2010Zhang et al , 2013Zhang et al , 2014Zhang et al , 2018. The high energy radiation beyond the X-ray band of the core region should be dominated by the synchrotron-self-compton scattering (SSC, Sikora et al 1994;Ghisellini et al 2009;Zhang et al 2013) process and/or the inverse scattering the photons of the broad-line region (IC/BLR, Ghisellini et al 2009;Zhang et al 2014Zhang et al , 2015 or torus (IC/torus, Sikora et al 2009;Kang et al 2014). The high energy (the X-ray-γ-ray bands) radiation mechanisms of large-scale jets are still debated (Harris & Krawczynski 2006;Zhang et al 2010;Meyer et al 2015;Zargaryan et al 2017).…”

Section: Introductionmentioning

confidence: 99%

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Jet Radiation Properties of 4C +49.22: from the Core to Large-scale Knots

Zhang

Yao

et al. 2018

ApJ

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4C +49.22 is a γ-ray flat spectrum radio quasar with a bright and knotty jet. We investigate the properties of the core and large-scale knots by using their spectral energy distributions (SEDs). Analyzing its Fermi /LAT data in the past 8 years, a long-term steady γ-ray emission component is found besides bright outbursts. For the core region, the γ-ray emission together with the simultaneous emission in the low-energy bands at different epochs is explained with the single-zone leptonic model. The derived magnetization parameters and radiation efficiencies of the radio-core jet decrease as γ-ray flux decays, likely indicating that a large part of the magnetic energy is converted to the kinetic energy of particles in pc-scale. For the large-scale knots, their radio-optical-X-ray SEDs can be reproduced with the leptonic model by considering the inverse Compton scattering of cosmic microwave background photons. The sum of the predicted γ-ray fluxes of these knots is comparable to that observed with LAT at ∼ 10 24 Hz of the steady γ-ray component, indicating that the steady γ-ray emission may be partially contributed by these large-scale knots. This may conceal the flux variations of the low-level γ-ray emission from the radio-core. The derived bulk Lorentz factors of the knots decrease along the distance to the core, illustrating as deceleration of jet in large-scale. The powers of the core and knots are roughly in the same order, but the jet changes from highly magnetized at the core region into particle-dominated at the large-scale knots.

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“…We note that the adopted value of a affects the feasibility of JCIs: values of α > 1 (e.g. Zhang et al 2015) make it more likely that BLR clouds penetrate powerful jets since JCIs require that R BLR > z min (see Eq. 1 and Sect.…”

Section: Broad-line Regionmentioning

confidence: 99%

Gamma rays from jets interacting with BLR clouds in blazars

Palacio

Bosch‐Ramon

Romero

2019

A&A

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Context. The innermost parts of powerful jets in active galactic nuclei are surrounded by dense, high-velocity clouds from the broadline region, which may penetrate into the jet and lead to the formation of a strong shock. Such jet-cloud interactions are expected to have measurable effects on the γ-ray emission from blazars. Aims. We characterise the dynamics of a typical cloud-jet interaction scenario, and the evolution of its radiative output in the 0.1-30 GeV energy range, to assess to what extent these interactions can contribute to the γ-ray emission in blazars. Methods. We use semi-analytical descriptions of the jet-cloud dynamics, taking into account the expansion of the cloud inside the jet and its acceleration. Assuming that electrons are accelerated in the interaction and making use of the hydrodynamical information, we then compute the high-energy radiation from the cloud, including the absorption of γ-rays in the ambient photon field through pair creation.Results. Jet-cloud interactions can lead to significant γ-ray fluxes in blazars with a broad-line region, in particular when the cloud expansion and acceleration inside the jet are taken into account. This is caused by 1) the increased shocked area in the jet, which leads to an increase in the energy budget for the non-thermal emission; 2) a more efficient inverse Compton cooling with the boosted photon field of the broad-line region; and 3) an increased observer luminosity due to Doppler boosting effects. Conclusions. For typical broad-line region parameters, either (i) jet-cloud interactions contribute significantly to the persistent γ-ray emission from blazars or (ii) the broad-line region is far from spherical or the fraction of energy deposited in non-thermal electrons is small.

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Preparation and stability of W/O/W emulsions containing sucrose as weighting agent

Cited by 21 publications

References 33 publications

Leptonic or Hadronic Emission: The X-Ray Radiation Mechanism of Large-scale Jet Knots in 3C 273

Leptonic or Hadronic Emission: The X-Ray Radiation Mechanism of Large-scale Jet Knots in 3C 273

Jet Radiation Properties of 4C +49.22: from the Core to Large-scale Knots

Gamma rays from jets interacting with BLR clouds in blazars

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