Related papers: Cosmic Rays in a Galactic Breeze
Recent accurate measurements of cosmic-ray (CR) protons and nuclei by ATIC-2, CREAM, and PAMELA reveal: a) unexpected spectral hardening in the spectra of CR species above a few hundred GeV per nucleon, b) a harder spectrum of He compared…
The discovery of the Fermi bubbles---a huge bilobular structure seen in GeV gamma-rays above and below the Galactic center---implies the presence of a large reservoir of high energy particles at $\sim 10 \, \text{kpc}$ from the disk. The…
In this paper we report the Fermi Large Area Telescope (LAT) detection of the gamma-ray emission toward the young star forming region W43. Using the latest source catalog and diffuse background models, the extended gamma-ray excess is…
Cosmic rays (CRs) are thought to be an important feedback mechanism in star-forming galaxies. They can provide an important source of pressure support and possibly drive outflows. We perform multidimensional CR-magnetohydrodynamic…
Cosmic rays (CRs) are dynamically important for the formation and evolution of galaxies by regulating star formation and by powering galactic outflows. However, to what extent CRs regulate galaxy formation depends on the coupling strength…
We discuss the production of $\gamma$-rays from cosmic rays (CR) in the circumgalactic medium (CGM) of Andromeda (M31) in light of the recent detection of $\gamma$-rays from an annular region of $\sim 5.5-120$ kpc away from the M31 disc. We…
The high energy activity in the inner few degrees of the Galactic center is traced by diffuse radio, X-ray and gamma-ray emission. The physical relationship between different components of diffuse gas emitting at multiple wavelengths is a…
The $\gamma$-ray emission from stars is induced by the interaction of cosmic rays with stellar atmospheres and photon fields. This emission is expected to come in two components: a stellar disk emission, where $\gamma$-rays are mainly…
We discuss a scenario in which the highest energy cosmic rays (CR's) and cosmological $\gamma$-ray bursts (GRB's) have a common origin. This scenario is consistent with the observed CR flux above $10^{20}\text{eV}$, provided that each burst…
Most of the celestial gamma rays detected by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons.…
The circumgalactic medium (CGM) contains information on the cumulative effect of galactic outflows over time, generally thought to be caused by feedback from star formation and active galactic nuclei. Observations of such outflows via…
Measurements of the low energy spectrum of Galactic Cosmic Rays (GCR) by detectors at or near the Earth are affected by Solar modulation. To overcome this difficulty, we consider nearby molecular clouds as GCR detectors outside the Solar…
Cosmic rays up to at least PeV energies are usually described in the framework of an elementary scenario that involves acceleration by objects that are located in the disk of the Milky Way, such as supernova remnants or massive star-forming…
We explore the impact of cosmic rays (CRs) on cosmological adaptive-mesh refinement simulations of a forming 10^12 Msolar halo, focusing on the circumgalactic medium (CGM), and its resulting low-redshift structure and composition. In…
Cosmic rays (CRs) can be studied through the galaxy-wide gamma-ray emission that they generate when propagating in the interstellar medium. The comparison of the diffuse signals from different systems may inform us about the key parameters…
We carry out a suite of simulations of the evolution of cosmic-ray (CR) driven, radiatively-cooled cold clouds embedded in hot material, as found in galactic outflows. In such interactions, CRs stream towards the cloud at the Alfv\'en…
Evidence has increasingly mounted in recent decades that outflows of matter and energy from the central parsecs of our Galaxy have shaped the observed structure of the Milky Way on a variety of larger scales. On scales of ~15 pc, the…
The interaction of cosmic rays (CRs) with magnetic fields and the interstelar medium (ISM) leads to the production of nonthermal radiation. Although this has been a topic of study for many years, it still poses many challenges to the…
Recent observations by CREAM and ATIC-2 experiments suggest that (1) the spectrum of cosmic ray (CR) helium is harder than that of CR proton below the knee 10^15 eV and (2) all CR spectra become hard at > 10^11 eV/n. We propose a new…
Galaxies with high star-formation rate surface densities often host large-scale outflows that redistribute energy, momentum, and baryons between the interstellar medium and the halo, making them a key feedback channel regulating galaxy…