Spatial Structure and Collisionless Electron Heating in Balmer‐dominated Shocks

Adelsberg, Matthew van; Heng, Kevin; McCray, Richard; Raymond, J. C.

doi:10.1086/592680

Cited by 109 publications

(156 citation statements)

References 38 publications

Supporting

Mentioning

149

Contrasting

Order By: Relevance

“…Similar to supernova remnants, cluster merger shocks are expected to be collisionless. In the shock in young supernova remnants, there is a well-known relation between the ratio of the ion and electron temperature T e /T i and shock velocity as T e /T i ∼ v −2 shock (van Adelsberg et al 2008). In the cluster case, nonequilibrium effects such as non-Maxwellian electron distributions (Kaastra et al 2009), nonequipartition of electrons and ions temperature (Takizawa 2005;Rudd & Nagai 2009;Akahori & Yoshikawa 2010), and nonequilibrium ionization are also expected.…”

Section: Possibility Of Nonequilibrium Effectsmentioning

confidence: 99%

SuzakuX-ray study of the double radio relic galaxy cluster CIZA J2242.8+5301

Akamatsu

Weeren

Ogrean

et al. 2015

A&A

105

View full text Add to dashboard Cite

Context. We present the results from Suzaku observations of the merging cluster of galaxies CIZA J2242.8+5301 at z = 0.192. Aims. To study the physics of gas heating and particle acceleration in cluster mergers, we investigated the X-ray emission from CIZA J2242.8+5301, which hosts two giant radio relics in the northern and southern part of the cluster. Methods. We analyzed data from three-pointed Suzaku observations of CIZA J2242.8+5301 to derive the temperature distribution in four different directions. Results. The intracluster medium (ICM) temperature shows a remarkable drop from 8.5 +0.8 −0.6 keV to 2.7 +0.7 −0.4 keV across the northern radio relic. The temperature drop is consistent with a Mach number M n = 2.7 +0.7 −0.4 and a shock velocity v shock:n = 2300 +700 −400 km s −1 . We also confirm the temperature drop across the southern radio relic. However, the ICM temperature beyond this relic is much higher than beyond the northern relic, which gives a Mach number M s = 1.7 +0.4 −0.3 and shock velocity v shock:s = 2040 +550 −410 km s −1 . These results agree with other systems showing a relationship between the radio relics and shock fronts which are induced by merging activity. We compare the X-ray derived Mach numbers with the radio derived Mach numbers from the radio spectral index under the assumption of diffusive shock acceleration in the linear test particle regime. For the northern radio relic, the Mach numbers derived from X-ray and radio observations agree with each other. Based on the shock velocities, we estimate that CIZA J2242.8+5301 is observed approximately 0.6 Gyr after core passage. The magnetic field pressure at the northern relic is estimated to be 9% of the thermal pressure.

show abstract

Section: Possibility Of Nonequilibrium Effectsmentioning

confidence: 99%

SuzakuX-ray study of the double radio relic galaxy cluster CIZA J2242.8+5301

Akamatsu

Weeren

Ogrean

et al. 2015

A&A

105

View full text Add to dashboard Cite

show abstract

“…There are several factors that determine the width of an Hα filament (e.g. van Adelsberg et al 2008), which are shock velocity, neutral fraction, and the pre-shock density. The width of the filament becomes larger when the velocity v s or neutral fraction f n increase and/or when the pre-shock density n 0 decreases.…”

Section: X-ray Synchrotron Emissionmentioning

confidence: 99%

The northwestern ejecta knot in SN 1006

Broersen

Vink

Miceli

et al. 2013

A&A

View full text Add to dashboard Cite

Aims. We want to probe the physics of fast collision-less shocks in supernova remnants. We are interested in the non-equilibration of temperatures and particle acceleration. Specifically, we aim to measure the oxygen temperature with regards to the electron temperature. In addition, we search for synchrotron emission in the northwestern thermal rim. Methods. This study is part of a dedicated deep observational project of SN 1006 using XMM-Newton, which provides us with the currently best resolution spectra of the bright northwestern oxygen knot. We aim to use the reflection grating spectrometer to measure the thermal broadening of the O  line triplet by convolving the emission profile of the remnant with the response matrix. Results. The line broadening was measured as σ e = 2.4 ± 0.3 eV, corresponding to an oxygen temperature of 275 +72 −63 keV. From the EPIC spectra we obtain an electron temperature of 1.35±0.10 keV. The difference in temperature between the species provides further evidence of non-equilibration of temperatures in a shock. In addition, we find evidence of a bow shock that emits X-ray synchrotron radiation, which is at odds with the general idea that because of the magnetic field orientation only in the NE and SW region, X-ray synchrotron radiation should be emitted. We find an unusual Hα and X-ray synchrotron geometry, in that the Hα emission peaks downstream of the synchrotron emission. This may be an indication of a peculiar Hα shock in which the density is lower and the neutral fraction is higher than in other supernova remnants, resulting in a peak in Hα emission further downstream of the shock.

show abstract

“…Steps forward in relaxing the fluid assumption have been made by [14] and [15], even if these works neglect the modification induced by neutrals upstream of the shock. A more reliable interpretation of Balmer line profile requires an accurate description of the CR acceleration process where the mutual interplay between CRs, neutrals, ionized plasma and magnetic turbulence is simultaneously taken into account.…”

Section: Introductionmentioning

confidence: 99%

Using optical lines to study particle acceleration at supernova remnants

Morlino

2014

Nuclear Physics B - Proceedings Supplements

View full text Add to dashboard Cite

The shocks of several young supernova remnants (SNR) are often associated with very thin optical filaments dominated by Balmer emission resulting from charge-exchange and collisional excitation between neutral Hydrogen from the interstellar medium and shocked protons and electrons. Optical lines are a direct probe of the conditions at the shock, in particular the width of the narrow and broad components reflect the temperature upstream and downstream of the shock, respectively. When the shock accelerate efficiently non-thermal particles, the shock structure changes producing anomalous Balmer lines and it is possible to use their line shape and their spatial profile to check the efficiency of SNR shocks in accelerating cosmic rays. Here we illustrate the kinetic theory of shock acceleration in presence of neutrals with some applications to young SNRs. We show that in three cases (RCW 86, SNR 0509-67.5 and Tycho) anomalous Balmer lines can be explained assuming that a fraction of ∼ 10% of the total shock kinetic energy is converted into not thermal particles, while in one single case, the northwestern part of SN 1006, there is no evidence of efficient acceleration.

show abstract

Spatial Structure and Collisionless Electron Heating in Balmer‐dominated Shocks

Cited by 109 publications

References 38 publications

SuzakuX-ray study of the double radio relic galaxy cluster CIZA J2242.8+5301

SuzakuX-ray study of the double radio relic galaxy cluster CIZA J2242.8+5301

The northwestern ejecta knot in SN 1006

Using optical lines to study particle acceleration at supernova remnants

Contact Info

Product

Resources

About