Conveners
Extragalactic diffuse & EBL
- Seth Digel (KIPAC/SLAC)
Understanding the physics of galaxy formation is an outstanding problem in modern astrophysics. Recent cosmological simulations have demonstrated that feedback by star formation, supernovae and active galactic nuclei appears to be critical in obtaining realistic disk galaxies and to slow down star formation to the small observed rates. However the particular physical processes underlying these...
Cosmic rays can be probed by their non-thermal emission in the radio and in gamma-ray bands. One-zone models of cosmic rays have been used to match the integrated emission of starburst galaxies. We construct multi-dimensional models of the local starburst M82 using cosmic ray propagation code GALPROP. Using the integrated gamma-ray and radio spectra, along with the vertical distribution of...
Following evidence for an east-west elongated virial ring around the Coma galaxy cluster in ~220GeV VERITAS data, we search for corresponding signatures in >GeV $\gamma$-rays from Fermi-LAT, and in soft, ~0.1keV X-rays from ROSAT.
For the ring elongation and orientation inferred from VERITAS, we find a 3.4$\sigma$ LAT excess, and a >5$\sigma$ modelled signature in the ROSAT R1+R2 bands; both...
The extragalactic background light (EBL), from ultra-violet to infrared, that encodes the emission from all stars, galaxies and actively accreting black holes in the observable Universe is critically important to probe models of star formation and galaxy evolution, but remains at present poorly constrained. The Large Area Telescope (LAT), on board Fermi, produced an unprecedented measurement...
The extragalactic background light (EBL) in the ultraviolet through optical absorbs gamma rays detectable by Fermi-LAT. We used the absorbed gamma-ray spectra of blazars to make the newest measurements of the EBL absorption optical depth. We fit these measurements with an EBL model that allows the cosmic star formation rate density (CSFRD) to vary, thus making the first accurate...
The aim of our work is to explore the Extra-galactic Unresolved Diffuse Emission of the Local Universe, cross-correlating Fermi LAT Pass8 data with the 2MPZ galaxy catalog.
The main idea behind the work is to use magnitude measurement in B and K band as a tracer respectively of star formation and mass amount, and to isolate the presence of AGNs in the 2MPZ catalog with available AGNs...
In the hierarchical paradigm of structure formation, galaxy clusters are the largest objects ever to virialize.
They are thought to grow by accreting mass through large scale, strong virial shocks.
Such a collisionless shock is expected to accelerate relativistic electrons, thus generating a spectrally flat leptonic virial ring.
However attempts to detect virial rings have all failed,...
The Fermi Large Area Telescope (LAT) has opened the way for comparative studies of cosmic-ray populations and high-energy sources in the Milky Way (MW) and in other external star-forming galaxies. Using more than 7 yr of LAT Pass 8 data in the energy range 0.1-100 GeV, M31 is detected at nearly 10 sigma and is observed to be extended at 4 sigma. Its spectrum is consistent with a power law and...
