Non-equilibrium chemistry and destruction of CO by X-ray flares

Mackey, Jonathan; Walch, Stefanie; Seifried, D.; Glover, Simon C. O.; Wünsch, Richard; Aharonian, F.

doi:10.1093/mnras/stz902

Cited by 34 publications

(34 citation statements)

References 147 publications

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“…We assume that molecular cloud is shielded from the interstellar radiation field. The ionization rate ζ of the molecular gas is assumed to be due to cosmic rays, but we notice that X-rays affect molecular gas similarly (Mackey et al 2019). The cosmic ray ionization rate 1 is allowed to take values in the range 10 −17 − 10 −14 s −1 .…”

Section: C-type Shock Modelmentioning

confidence: 99%

C-type shock modelling – the effect of new H2–H collisional rate coefficients

Nesterenok

Bossion

Scribano

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We consider collisional excitation of H 2 molecules in C-type shocks propagating in dense molecular clouds. New data on collisional rate coefficients for (de-)excitation of H 2 molecule in collisions with H atoms and new H 2 dissociation rates are used. The new H 2 -H collisional data are state of the art and are based on the most accurate H 3 potential energy surface. We re-examine the excitation of rotational levels of H 2 molecule, the para-to-ortho-H 2 conversion, and H 2 dissociation by H 2 -H collisions. At cosmic ray ionization rates ζ 10 −16 s −1 and at moderate shock speeds, the H/H 2 ratio at the shock front is mainly determined by the cosmic ray ionization rate. The H 2 -H collisions play the main role in the para-to-ortho-H 2 conversion and, at ζ 10 −15 s −1 , in the excitation of vibrationally excited states of H 2 molecule in the shock. The H 2 ortho-to-para ratio (OPR) of the shocked gas and column densities of rotational levels of vibrationally excited states of H 2 are found to depend strongly on the cosmic ray ionization rate. We discuss the applicability of the presented results to interpretation of observations of H 2 emission in supernova remnants.

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Section: C-type Shock Modelmentioning

confidence: 99%

C-type shock modelling – the effect of new H2–H collisional rate coefficients

Nesterenok

Bossion

Scribano

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…Figure 1 shows the evolution of the X-ray emission compared to measurements from Type-IIn and Type-IIP SNs respectively. We accounted for potential absorption in the remnant itself and in the dense ISM, calculating the optical depth based on the hydrogen-density from our simulation and the cross-section given by [15,19]. We are likely slightly overestimating the absorption since we can not considering the ionization-state of…”

Section: Resultsmentioning

confidence: 99%

Gamma-ray emission from young supernova remnants in dense circumstellar environments

Brose¹,

Mackey²,

Sushch³

2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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Supernova remnants are known to accelerate cosmic rays (CRs) on account of their non-thermal emission of radio waves, X-rays, and gamma rays. However, the ability to accelerate CRs up to PeV-energies has yet to be demonstrated. The presence of cut-offs in the gamma-ray spectra of several young SNRs led to the idea that PeV energies might only be achieved during the very initial stages of a remnant's evolution. We use the time-dependent acceleration code RATPaC to study the acceleration of cosmic rays in supernovae expanding into dense environments around massive stars, where the plentiful target material might offer a path to the detection of gammarays by current and future experiments. We performed spherically symmetric 1-D simulations in which we simultaneously solve the transport equations for cosmic rays, magnetic turbulence, and the hydrodynamical flow of the thermal plasma in the test-particle limit. We investigated typical parameters of the circumstellar medium (CSM) in the freely expanding winds around red supergiant (RSG) and luminous blue variable (LBV) stars. The maximum achievable energy might be limited to sub-PeV energies despite strong magnetic fields close to the progenitor star that enhance turbulence-damping by cascading: we find a maximum CR energy of 100-200 TeV, reached within one month after explosion. The peak luminosity for a LBV progenitor is 10 43 erg s −1 (10 42 erg s −1 ) at GeV (TeV) energies and, for a RSG progenitor, 10 41 erg s −1 (10 40 erg s −1 ). All calculated SNe reach their peak gamma-ray luminosity after 1 month and then fade at a rate ∼ −1 , as long as the SN shock remains in the freely expanding wind of the progenitor. Potentially detectable gamma-ray signals can be expected in the Fermi-LAT waveband weeks to months after an explosion into a freely expanding wind.

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Section: Resultsmentioning

confidence: 99%

Non-thermal emission from young supernova remnants in dense circumstellar environments

Brose,

Mackey,

Sushch

2021

Preprint

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Supernova remnants are known to accelerate cosmic rays (CRs) on account of their non-thermal emission of radio waves, X-rays, and gamma rays. However, the ability to accelerate CRs up to PeV-energies has yet to be demonstrated. The presence of cut-offs in the gamma-ray spectra of several young SNRs led to the idea that PeV energies might only be achieved during the very initial stages of a remnant's evolution. We use the time-dependent acceleration code RATPaC to study the acceleration of cosmic rays in supernovae expanding into dense environments around massive stars, where the plentiful target material might offer a path to the detection of gammarays by current and future experiments. We performed spherically symmetric 1-D simulations in which we simultaneously solve the transport equations for cosmic rays, magnetic turbulence, and the hydrodynamical flow of the thermal plasma in the test-particle limit. We investigated typical parameters of the circumstellar medium (CSM) in the freely expanding winds around red supergiant (RSG) and luminous blue variable (LBV) stars. The maximum achievable energy might be limited to sub-PeV energies despite strong magnetic fields close to the progenitor star that enhance turbulence-damping by cascading: we find a maximum CR energy of 100-200 TeV, reached within one month after explosion. The peak luminosity for a LBV progenitor is 10 43 erg s −1 (10 42 erg s −1 ) at GeV (TeV) energies and, for a RSG progenitor, 10 41 erg s −1 (10 40 erg s −1 ). All calculated SNe reach their peak gamma-ray luminosity after 1 month and then fade at a rate ∼ 𝑡 −1 , as long as the SN shock remains in the freely expanding wind of the progenitor. Potentially detectable gamma-ray signals can be expected in the Fermi-LAT waveband weeks to months after an explosion into a freely expanding wind.

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Non-equilibrium chemistry and destruction of CO by X-ray flares

Cited by 34 publications

References 147 publications

C-type shock modelling – the effect of new H2–H collisional rate coefficients

C-type shock modelling – the effect of new H2–H collisional rate coefficients

Gamma-ray emission from young supernova remnants in dense circumstellar environments

Non-thermal emission from young supernova remnants in dense circumstellar environments

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