ERRATUM: “THE RELATION BETWEEN POST-SHOCK TEMPERATURE, COSMIC-RAY PRESSURE, AND COSMIC-RAY ESCAPE FOR NON-RELATIVISTIC SHOCKS” (2010, ApJ, 722, 1727)

Summary The aim of this study was to evaluate different post-shock temperatures for tetraploid induction in the yellowtail tetra Astyanax altiparanae. Newly fertilized eggs were divided into four groups, three were submitted to heat shock (40°C for 2 min) at 24 min post-fertilization (mpf) and another group remained without shock (control). Groups submitted to temperature shock were further separated at the following temperatures: 22°C, 26°C and 28°C. Survival among embryonic development was counted and at hatching the ploidy was analyzed by flow cytometry. The results showed that the post-shock temperature affects the parameters analyzed and, therefore, must be considered for optimization of the production of tetraploid in A. altiparanae. Those data are innovative and could be used in future studies of basic biology in this species.

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Balmer-dominated shocks in Tycho’s SNR: omnipresence of CRs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317004550 ◽

2017 ◽

Vol 12 (S331) ◽

pp. 248-253

Author(s):

Sladjana Knežević ◽

Ronald Läsker ◽

Glenn van de Ven ◽

Joan Font ◽

John C. Raymond ◽

...

Keyword(s):

Line Width ◽

Cosmic Ray ◽

Wide Field ◽

Hydrogen Atoms ◽

Narrow Line Width ◽

Shock Region ◽

Bayesian Evidence ◽

Post Shock ◽

Spurious Result ◽

First Time

AbstractWe present wide-field, spatially and highly resolved spectroscopic observations of Balmer filaments in the northeastern rim of Tycho’s supernova remnant in order to investigate the signal of cosmic-ray (CR) acceleration. The spectra of Balmer-dominated shocks (BDSs) have characteristic narrow (FWHM ~ 10 km s−1) and broad (FWHM ~ 1000 km s−1) Hα components. CRs affect the Hα-line parameters: heating the cold neutrals in the interstellar medium results in broadening of the narrow Hα-line width beyond 20 km s−1, but also in reduction of the broad Hα-line width due to energy being removed from the protons in the post-shock region. For the first time we show that the width of the narrow Hα line, much larger than 20 km s−1, is not a resolution or geometric effect nor a spurious result of a neglected intermediate (FWHM ~ 100 km s−1) component resulting from hydrogen atoms undergoing charge exchange with warm protons in the broad-neutral precursor. Moreover, we show that a narrow line width ≫ 20 km s−1extends across the entire NE rim, implying CR acceleration is ubiquitous, and making it possible to relate its strength to locally varying shock conditions. Finally, we find several locations along the rim, where spectra are significantly better explained (based on Bayesian evidence) by inclusion of the intermediate component, with a width of 180 km s−1on average.

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Estimate of Plasma Temperatures Across a CME-Driven Shock from a Comparison Between EUV and Radio Data

Solar Physics ◽

10.1007/s11207-020-01686-0 ◽

2020 ◽

Vol 295 (9) ◽

Author(s):

Federica Frassati ◽

Salvatore Mancuso ◽

Alessandro Bemporad

Keyword(s):

Shock Wave ◽

Compression Ratio ◽

Emission Measure ◽

Type Ii ◽

Solar Dynamics Observatory ◽

Radio Data ◽

Shock Temperature ◽

Post Shock ◽

Dem Analysis ◽

Solar Dynamics

Abstract In this work, we analyze the evolution of an EUV wave front associated with a solar eruption that occurred on 30 October 2014, with the aim of investigating, through differential emission measure (DEM) analysis, the physical properties of the plasma compressed and heated by the accompanying shock wave. The EUV wave was observed by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) and was accompanied by the detection of a metric Type II burst observed by ground-based radio spectrographs. The EUV signature of the shock wave was also detected in two of the AIA channels centered at 193 Å and 211 Å as an EUV intensity enhancement propagating ahead of the associated CME. The density compression ratio $X$ X of the shock as inferred from the analysis of the EUV data is $X \approx 1.23$ X ≈ 1.23 , in agreement with independent estimates obtained from the analysis of the Type II band-splitting of the radio data and inferred by adopting the upstream–downstream interpretation. By applying the Rankine–Hugoniot jump conditions under the hypothesis of a perpendicular shock, we also estimate the temperature ratio as $T_{\mathrm{D}}/T_{\mathrm{U}} \approx 1.55$ T D / T U ≈ 1.55 and the post-shock temperature as $T_{\mathrm{D}}\approx 2.75$ T D ≈ 2.75 MK. The modest compression ratio and temperature jump derived from the EUV analysis at the shock passage are typical of weak coronal shocks.

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Cosmic-ray hydrodynamics at relativistic shocks

The Astrophysical Journal ◽

10.1086/166559 ◽

1988 ◽

Vol 331 ◽

pp. 336 ◽

Cited By ~ 7

Author(s):

J. G. Kirk ◽

G. M. Webb

Keyword(s):

Cosmic Ray ◽

Relativistic Shocks

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Reaching thermal noise at ultra-low radio frequencies

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038663 ◽

2020 ◽

Vol 642 ◽

pp. A85 ◽

Cited By ~ 1

Author(s):

F. de Gasperin ◽

G. Brunetti ◽

M. Brüggen ◽

R. van Weeren ◽

W. L. Williams ◽

...

Keyword(s):

Thermal Noise ◽

Signal To Noise Ratio ◽

Low Frequency ◽

Galaxy Cluster ◽

Cosmic Ray ◽

Radio Halo ◽

Cosmic Ray Acceleration ◽

The Galaxy ◽

Background Turbulence ◽

Post Shock

Context. Ultra-low frequency observations (< 100 MHz) are particularly challenging because they are usually performed in a low signal-to-noise ratio regime due to the high sky temperature and because of ionospheric disturbances whose effects are inversely proportional to the observing frequency. Nonetheless, these observations are crucial for studying the emission from low-energy populations of cosmic rays. Aims. We aim to obtain the first thermal-noise limited (∼1.5 mJy beam−1) deep continuum radio map using the Low Frequency Array’s Low Band Antenna (LOFAR LBA) system. Our demonstration observation targeted the galaxy cluster RX J0603.3+4214 (known as the Toothbrush cluster). We used the resulting ultra-low frequency (39–78 MHz) image to study cosmic-ray acceleration and evolution in the post shock region considering the presence of a radio halo. Methods. We describe the data reduction we used to calibrate LOFAR LBA observations. The resulting image was combined with observations at higher frequencies (LOFAR 150 MHz and VLA 1500 MHz) to extract spectral information. Results. We obtained the first thermal-noise limited image from an observation carried out with the LOFAR LBA system using all Dutch stations at a central frequency of 58 MHz. With eight hours of data, we reached an rms noise of 1.3 mJy beam−1 at a resolution of 18″ × 11″. Conclusions. The procedure we developed is an important step towards routine high-fidelity imaging with the LOFAR LBA. The analysis of the radio spectra shows that the radio relic extends to distances of 800 kpc downstream from the shock front, larger than what is allowed by electron cooling time. Furthermore, the shock wave started accelerating electrons already at a projected distance of < 300 kpc from the crossing point of the two clusters. These results may be explained by electrons being re-accelerated downstream by background turbulence, possibly combined with projection effects with respect to the radio halo.

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KINETIC SIMULATIONS OF THE CURRENT-DRIVEN INSTABILITY IN COSMIC RAY MODIFIED RELATIVISTIC SHOCKS

International Journal of Modern Physics D ◽

10.1142/s0218271808013431 ◽

2008 ◽

Vol 17 (10) ◽

pp. 1803-1809 ◽

Cited By ~ 2

Author(s):

M. A. RIQUELME ◽

A. SPITKOVSKY

Keyword(s):

Cosmic Ray ◽

Back Reaction ◽

Speed Of Light ◽

One Dimensional ◽

Particle In Cell ◽

Nonlinear Properties ◽

Relativistic Shock ◽

Relativistic Shocks ◽

Viable Mechanism ◽

Alfven Velocity

We study the current-driven instability predicted by Bell (2004) using particle-in-cell simulations. We use one-dimensional simulations to test the dispersion relation and the nonlinear properties of the instability for the case of a relativistic shock front under idealized conditions. We find that if the cosmic rays (CR) are energetic enough to not get deflected by the generated magnetic field, the instability can grow exponentially until the Alfvén velocity of the plasma becomes comparable to the speed of light. We also use one- and two-dimensional simulations to study the effect of the back reaction of the instability on CR. We find that the deflection and filamentation of CR and background plasma play an important role in the saturation of the instability. The current-driven instability is a viable mechanism for the amplification of magnetic fields in both non-relativistic and relativistic shock environments.

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Probing the effects of hadronic acceleration at the SN 1006 shock front

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313009642 ◽

2013 ◽

Vol 9 (S296) ◽

pp. 315-319

Author(s):

Marco Miceli ◽

F. Bocchino ◽

A. Decourchelle ◽

G. Maurin ◽

J. Vink ◽

...

Keyword(s):

Particle Acceleration ◽

Spectral Analysis ◽

Supernova Remnants ◽

Supernova Remnant ◽

Ambient Medium ◽

Cosmic Ray ◽

X Ray ◽

Spatially Resolved ◽

Large Program ◽

Post Shock

AbstractSupernova remnant shocks are strong candidates for being the source of energetic cosmic rays and hadron acceleration is expected to increase the shock compression ratio, providing higher post-shock densities. We exploited the deep observations of the XMM-Newton Large Program on SN 1006 to verify this prediction. Spatially resolved spectral analysis led us to detect X-ray emission from the shocked ambient medium in SN 1006 and to find that its density significantly increases in regions where particle acceleration is efficient. Our results provide evidence for the effects of acceleration of cosmic ray hadrons on the post-shock plasma in supernova remnants.

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WITHDRAWN: Cosmic ray acceleration at relativistic shocks, shear layers, ...

New Astronomy Reviews ◽

10.1016/j.newar.2008.03.008 ◽

2008 ◽

Cited By ~ 1

Author(s):

Michał Ostrowski

Keyword(s):

Cosmic Ray ◽

Shear Layers ◽

Relativistic Shocks ◽

Cosmic Ray Acceleration

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Active Galactic Nuclei: Jets as the Source of Hadrons and Neutrinos

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2014.01.0269 ◽

2014 ◽

Vol 1 (1) ◽

pp. 269-273

Author(s):

Athina Meli ◽

Paolo Ciarcelluti

Keyword(s):

Active Galactic Nuclei ◽

Gamma Ray ◽

Galactic Nuclei ◽

Cosmic Ray ◽

High Energy ◽

Plasma Jets ◽

Shock Acceleration ◽

Fermi Acceleration ◽

Acceleration Mechanism ◽

Relativistic Shocks

Active galactic nuclei are extragalactic sources, and their relativistic hot-plasma jets are believed to be the main candidates of the cosmic-ray origin, above the so-called knee region of the cosmic-ray spectrum. Relativistic shocks, either single or multiple, have been observed or been theorized to be forming within relativistic jet channels in almost all active galactic nuclei sources. The acceleration of non-thermal particles (e.g. electrons, protons) via the shock Fermi acceleration mechanism, is believed to be mainly responsible for the power-law energy distribution of the observed cosmic-rays, which in very high energies can consequently radiate high energy gamma-rays and neutrinos, through related radiation channels. Here, we will focus on the primary particle (hadronic) shock acceleration mechanism, and we will present a comparative simulation study of the properties of single and multiple relativistic shocks, which occur in AGN jets. We will show that the role of relativistic (quasi-parallel either quasi-perpendicular) shocks, is quite important since it can dramatically alter the primary CR spectral indices and acceleration eciencies. These properties being carried onto gamma-ray and neutrino radiation characteristics, makes the combination of them a quite appealing theme for relativistic plasma and shock acceleration physics, as well as observational cosmic-ray, gamma-ray and neutrino astronomy.

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