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COSMAX, Cosmic accelerators at home


The COSMAX project aims at allowing anyone interested to have a glimpse at the ever-changing gamma-ray sky. Periods where particularly interesting and spectacular events (solar outburts, gamma-ray bursts, flaring actrive galactic nuclei, novas….) took place can be selected, or alternatively the sky can be watched « live ». The project makes use of the publicly-available data of the Large Area Telescope (LAT) aboard the NASA Fermi satellite. The goal is to increase the awareness of the general public towards violent phenomena of the Universe, all exhibiting extraordinary properties, with some of them showing strong temporal variability (or a transient character) contrasting with the seemingly steadiness of the sky.

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Cosmic rays detected at Earth are direct (and historically the earliest one, since the 100th anniversary of their discovery was celebrated in 2012) evidence for the existence of cosmic accelerators in the Universe. The nature of these accelerators long remained a mystery, mainly because cosmic rays are randomly deflected in the magnetic fields permeating the cosmos. The information related to their direction is thus lost.

Gamma rays are a privileged means to study gamma cosmic accelerators, whether they are the sources of cosmic rays or otherwise : gamma-rays are only produced by high-energy particles interacting with matter, magnetic fields or low-energy electromagnetic radiations (like visible light) and are immune to magnetic deflection. Different accelerator classes including pulsars, supernova remnants, X-ray binaries, novae, active galactic nuclei, gamma-ray bursts… have been detected in gamma rays. Thanks to its exceptional data, the Fermi-LAT (Large Area Telescope) has allowed a major leap forward in our knowledge of these objects. The possibility of exploring the Fermi-LAT data in a simple fashion rests on several unique properties shown by these data: they are public (as are all analysis tools), span the entire sky (the sky is surveyed every 3 hours), quite easy to comprehend (consisting of a simple list of photon parameters: sky coordinates, energy, detection time...) and quickly available (less than 12 hours elapsed between the detection and the posting on the internet). It is thus possible for non-experts to generate full sky maps (or restricted to user-defined regions) similar to those illustrating most of the LAT press releases. Many of these press releases report interesting transient events (e.g., spectacular flares experienced by different sources). The sky can also be watched “live” by using the very latest data (bright flaring sources detected at any given moment are listed on the Fermi blog at The brightness variations can be followed as a function of time as well.


Installation instructions are given in the COSMAX tutorial document (pages 5-9).

VMWare Scilinux5.7 (mostly for PC owners, as VMWare does not offer free software for Macs)

VirtualBox Scilinux 5.7 (.vbox and .vmdk) (NEW! April 26, 2016. For both Mac and PC owners)

Linux tar file