Leben und Werk

We present the results of a joint spectral analysis of RXTE PCA, ASCA SIS, and ROSAT PSPC data of the supernova remnant SN 1006. This work represents the first attempt to model both the thermal and nonthermal X-ray emission over the entire X-ray energy band. The thermal flux is described by a nonequilibrium ionization model with an electron temperature kT e = 0.6 keV, an ionization timescale n 0 t = 9 × 10 9 cm −3 s, and a relative elemental abundance of silicon that is 10-18 times larger than the solar abundance. The nonthermal X-ray spectrum is described by a broken power law model with low-and high-energy photon indices Γ 1 = 2.1 and Γ 2 = 3.0, respectively. Since the nonthermal X-ray spectrum steepens with increasing energy, the results of the present analysis corroborate previous claims that the nonthermal X-ray emission is produced by synchrotron radiation. We argue that the magnetic field strength is significantly larger than previous estimates of about 10 µG and arbitrarily use a value of 40 µG to estimate the parameters of the cosmic-ray electron, proton, and helium spectra of the remnant. The results for the ratio of the number densities of protons and electrons (R = 160 at 1 GeV), the total energy in cosmic rays (E cr = 1 × 10 50 ergs), and the spectral index of the electrons at 1 GeV (Γ e = 2.14 ± 0.12) are consistent with the hypothesis that Galactic cosmic rays are accelerated predominantly in the shocks of supernova remnants. Yet, the remnant may or may not accelerate nuclei to energies as high as the energy of the "knee," depending on the reason why the maximum energy of the electrons is only 10 TeV.

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“…9). Within the rather large uncertainties of our estimates, this ratio is consistent with the ratio observed at Earth (Meyer 1969).…”

Section: Cosmic Rayssupporting

confidence: 90%

X‐Ray Synchrotron Emission from 10–100 TeV Cosmic‐Ray Electrons in the Supernova Remnant SN 1006

Allen

Petre

Gotthelf

2001

ApJ

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“…Assuming that ∼ 10% of the energy goes into non-thermal protons, the inferred electron-to-proton injection ratio at > ∼ GeV energies is Kep ∼ 0.01. This value is in agreement with the observed cosmic ray composition at Earth (e.g., Meyer 1969;Picozza et al 2013). On the other hand, if we assume equipartition between the non-thermal protons and magnetic field, p ∼ B ∼ 0.2, then one finds e ∼ 0.008 and Kep ∼ 0.002 in agreement with particle-in-cell simulations (e.g., Park et al 2015) and modeling of young SNRs at X-rays and GeV energies (e.g., Völk et al 2005).…”

Section: Discussionsupporting

confidence: 92%

Radio SNRs in the Magellanic Clouds as probes of shock microphysics

Duran

Whitehead

Giannios

2016

Monthly Notices of the Royal Astronomical Society: Letters

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A large number of supernova remnants (SNRs) in our Galaxy and galaxies nearby have been resolved in various radio bands. This radio emission is thought to be produced via synchrotron emission from electrons accelerated by the shock that the supernova ejecta drives into the external medium. Here we consider the sample of radio SNRs in the Magellanic Clouds. Given the size and radio flux of a SNR, we seek to constrain the fraction of shocked fluid energy in non-thermal electrons ( e ) and magnetic field ( B ), and find e B ∼ 10 −3 . These estimates do not depend on the largely uncertain values of the external density and the age of the SNR. We develop a Monte Carlo scheme that reproduces the observed distribution of radio fluxes and sizes of the population of radio SNRs in the Magellanic Clouds. This simple model provides a framework that could potentially be applied to other galaxies with complete radio SNRs samples.

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Leben und Werk

Cited by 2 publications

References 17 publications

X‐Ray Synchrotron Emission from 10–100 TeV Cosmic‐Ray Electrons in the Supernova Remnant SN 1006

X‐Ray Synchrotron Emission from 10–100 TeV Cosmic‐Ray Electrons in the Supernova Remnant SN 1006

Radio SNRs in the Magellanic Clouds as probes of shock microphysics

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