CONSTRAINTS ON COSMIC-RAY PROPAGATION MODELS FROM A GLOBAL BAYESIAN ANALYSIS

By Igor V. Moskalenko, Roberto Trotta, G. Jóhannesson, Troy A. Porter, R. Ruiz de Austri, A. Strong. 2010

255 citations recorded by the source corpus.

Research in many areas of modern physics such as, e.g., indirect searches for dark matter and particle acceleration in supernova remnant shocks rely heavily on studies of cosmic rays (CRs) and associated diffuse emissions (radio, microwave, X-rays, γ-rays). While very detailed numerical models of CR propagation exist, a quantitative statistical analysis of such models has been so far hampered by the large computational effort that those models require. Although statistical analyses have been carried out before using semi-analytical models (where the computation is much faster), the evaluation of the results obtained from such models is difficult, as they necessarily suffer from many simplifying assumptions. The main objective of this paper is to present a working method for a full Bayesian parameter estimation for a numerical CR propagation model. For this study, we use the GALPROP code, the most advanced of its kind, which uses astrophysical information, and nuclear and particle data as inputs to self-consistently predict CRs, γ-rays, synchrotron, and other observables. We demonstrate that a full Bayesian analysis is possible using nested sampling and Markov Chain Monte Carlo methods (implemented in the SuperBayeS code) despite the heavy computational demands of a numerical propagation code. The best-fit values of parameters found in this analysis are in agreement with previous, significantly simpler, studies also based on GALPROP.

Subfields: Nuclear and High Energy Physics, Radiation

View Paper: https://www.semanticscholar.org/paper/f93055049344c7dc3ac74ee40f60b8521125c325

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Nuclear and High Energy Physics

1. A. Strong
2. E. Orlando
3. E. Amato
4. Troy A. Porter
5. P. Serpico
6. T. Jaffe
7. I. Grenier
8. G. Zaharijas

In Radiation

1. R. Cameron

Citations in the corpus

• The Nine Lives of Cosmic Rays in Galaxies (2015, background): “The scale-height of the CR halo can be constrained by the 10Be/9Be ratio but is still uncertain (Putze, Derome & Maurin 2010; Strong, Moskalenko & Ptuskin 2007; Trotta et al. 2011).”
• Theoretical Challenges in Galaxy Formation (2016, unknown): “The propagation of cosmic rays through the ISM is complex and often approximated by diffusion with coefficients of the order κCR ∝ 1028−1029cms−1 (e.g. Strong & Moskalenko 1998, Tabatabaei et al. 2013, Trotta et al. 2011).”
• Diffusive propagation of cosmic rays from supernova remnants in the Galaxy. I: spectrum and chemical composition (2011, methodology): “st expression clarifies that the flux of CRs scales with H/D(E), a result that remains valid even in more complex versions of the calculation and in fact found also in propagation codes such as GALPROP [19] and DRAGON [26]. The second expression in Eq. 3.3 clarifies that the observed density of CRs is ”
• FERMI-LAT OBSERVATIONS OF HIGH-ENERGY γ-RAY EMISSION TOWARD THE GALACTIC CENTER (2015, background): “This halo height is the closest in the IEM grid7 to the halo height distribution mean (∼ 5.5 kpc) determined by Trotta et al. (2011); the exact value of the halo height is not critical for the analysis.”
• The interstellar cosmic-ray electron spectrum from synchrotron radiation and direct measurements. (2011, background): “An extensive review of CR propagation including electrons can be found in Strong et al. (2007); a recent global viewpoint for the Milky Way is given in Strong et al. (2010), and a propagation parameter study in Trotta et al. (2011).”
• PROBING THE PULSAR ORIGIN OF THE ANOMALOUS POSITRON FRACTION WITH AMS-02 AND ATMOSPHERIC CHERENKOV TELESCOPES (2013, methodology): “Specifically, we employ here the best-fitting Bayesian model of Trotta et al. (2011), which finds a posterior mean for the diffusion constant of 8.32×1028 cm2s−1, normalized at 4 GeV, with an energy index δ = 0.3, nearly equivalent to that first proposed by Kolmogorov (1941).”
• Astrophysical models for the origin of the positron (2011, background): “Of course, the need for an additional component can be confirmed in more refined statistical analyses, see [29, 30, 31], but we believe that it is important to stress the simplicity and generality of the basic argument.”