Cosmic-ray-induced H₂ line emission

Time Delays in Cosmic Ray Propagation

Cosmic Rays (CR) travel at speeds essentially indistinguishable from the speed of light. However whilst travelling through magnetic fields, both regular and turbulent, they are delayed behind the light since they are usually charged particles and their paths are not linear. Those delays can be so long that they are an impediment to correctly identifying sources which may be variable in time. Fu...

Detecting Radio Emission from Cosmic Ray

GRB hosts through cosmic time ∗ VLT / X - Shooter emission - line spectroscopy † of 96 γ - ray - burst -

We present data and initial results from VLT/X-Shooter emission-line spectroscopy of 96 galaxies selected by long γ-ray bursts (GRBs) at 0.1 < z < 3.6, the largest sample of GRB host spectra available to date. Most of our GRBs were detected by Swift and 76% are at 0.5 < z < 2.5 with a median zmed ∼ 1.6. Based on Balmer and/or forbidden lines of oxygen, nitrogen, and neon, we measure systemic re...

Iron line emission in X–ray afterglows

Recent observations of X–ray afterglows reveal the presence of a redshifted Kα iron line in emission in four bursts. In GRB 991216, the line was detected by the low energy grating of Chandra, which showed the line to be broad, with a full width of ∼15,000 km s. These observations indicate the presence of a > 1 M⊙ of iron rich material in the close vicinity of the burst, most likely a supernova ...

X - and Gamma - Ray Line Emission Processes

This chapter is intended to provide a general presentation of the atomic and nuclear processes responsible for X-ray line and gamma-ray line emission in various astrophysical environments. I consider line production from hot plasmas, from accelerated particle interactions , from the decay of radioactive nuclei synthesized in stars and from positron annihilation. Spectroscopic properties of thes...