MEGAlib - The Medium Energy Gamma-ray Astronomy software library

What is MEGAlib?

The Medium Energy Gamma-ray Astronomy library (MEGAlib) is a set of software tools, which are primarily designed to analyze data of the next generation of Compton telescopes. The library comprises all necessary data analysis steps from simulation/measurements via event reconstruction to image reconstruction.

MEGAlib contains a geometry and detector description tool for the detailed modeling of different detector types and characteristics, and provides interfaces for the simulation tools Geant3, MGeant/MGGPOD and Geant4. For the different Compton telescope candidate detector types (electron tracking, multiple Compton or time of flight based) specialized event reconstruction algorithms are implemented in different approaches (Chi-square and Bayesian). The high level data analysis tools allow to calculate response matrices, reconstruct images (list-mode likelihood algorithm), determine detector resolutions and sensitivities, retrieve spectra, determine polarization modulations, etc.

The highly modular and completely object-oriented library is written in C++ and utilizes ROOT. While it has been originally developed for MEGA, it also has been successfully applied to a wide variety of hard X-ray/gamma-ray telescopes, such as ACT, NCT, NuSTAR, or GRI.

For a general overview consider reading "MEGAlib - Medium Energy Gamma-ray Astronomy Library", or "MEGAlib - Simulation and Data Analysis for Low-to-medium-energy Gamma-ray Telescopes". For details about the algorithms refer to Andreas Zoglauer, "First Light for the Next Generation of Compton and Pair Telescopes" and Florian Schopper, "Entwicklung eines Teleskops zur Abbildung von Gammastrahlung mittels Comptonstoss und Paarerzeugung". For a detailed insight into simulations with Cosima see "Cosima - the Cosmic Simulator of MEGAlib"

Moreover, you might want to take a look at the following posters: "MEGAlib - Simulation and Data Analysis for Low-to-medium-energy Gamma-ray Telescopes" and "Geomega: MEGAlib's geometry and detector description tool for Geant3, MGGPOD, and Geant4"

Requirements

The latest stable release requires the following software components:

1. A fully functional up-to-date Linux OS or Mac OS X (v10.5 or higher) - Windows is definitely not supported and Cygwin has never been tested. The status of the different UNIX systems is unknown (simply because it has not been tested). The reference systems (i.e. the system used to code MEGAlib) is SUSE 11.2 and Ubuntu 9.10. If you want to use anything else, especially newer, you might have to make things compatible by yourself!
2. In addition, make sure you have installed at least gcc 3.3 or icc 11.0.
3. Install ROOT (version 5.22 or higher with the latest patch - do not use a development version (uneven numbers) such as 5.23 or 5.25 or 5.27).
4. It is highly recommended to also install Geant4 (version 9.2 with the latest patch) and completely integrate Mark Kippens G4LECS package into Geant4 before you compile it (i.e. copy the source and header files named G4LECS* into the appropriate directories of the low-energy package)!
5. If you want to do MGGPOD simulations: Install the latest version of Georg Weidenspointner's MGGPOD. In addition you need also the FTOOLS.

License

MEGAlib can be used freely for any astrophysical and/or nuclear science application on the condition that MEGAlib is correctly cited in all resulting publications. However, MEGAlib (or any part of it) may not be used for any commercial or military purposes.

The master reference is:

For more details see the license file.

Download

cvs - Recommended!

If you want the latest version (which is always recommended), or plan to do some development yourself, you should retrieve the sources from the cvs directory. I never check in anything which I expect not to work, thus using this version shoulf be safe. Please use :pserver:anonymous@cvs.mpe.mpg.de:/home/zoglauer/Repository as $CVSROOT. The password for the user anonymous is gamma-ray. This gives you read-only access to the analysis part of MEGAlib. For write access or access to the hardware classes you have to contact me personally! For more details see: MEGAlib/doc/Installation.pdf

tar ball

A tar-ball with the latest publicly available version of MEGAlib can be downloaded from here:

It includes Geomega, Sivan, Revan, Mimrec, Cosima, etc., but excludes hardware related software such as MEGAlyze. This version is in feature freeze but is patched with all bug-fixes from the current development tree.

There is a special web page for older versions.

Preinstalled Ubuntu VirtualBox machine

For testing purposes a VirtualBox is available with MEGAlib and all necessary software already preinstalled in the form of the "Open Virtualization Format":

You need to download both files into the same directory and then use the "Import Appliance" feature in VirtualBox (requires VirtualBox 2.2 and higher) to import the virtual box. The installed operating system is Ubuntu 8.04 LTS. The user name is "megalib", the user/root password is also "megalib". MEGAlib is installed in "~/Science/Software/MEGAlib", all external software such as ROOT, Geant4, LHEASoft, etc. can be found in "~/Science/Software/External". It is adviced to install the VirtualBox "guest additions" for improved performance.

This VirtualBox is NOT updated on a regular basis! To update MEGAlib, simply switch into the MEGAlib directory "cd ~/Science/Software/MEGAlib", call "cvs update", "./configure -linux -optimized", and recompile: "make"

Installation

You can find a detailed installation description in the file MEGAlib/doc/Installation.pdf

If you have trouble setting up your system, you might consider downloading the VirtualBox, and then take a look at the setup, e.g. all the environment variables in "~/.bashrc.local".

Please take also a look at the change log for the important changes between the versions: ChangeLog.txt

Documentation

The definitely not complete documentation can be found in these pdf-file: MEGAlib (general overview, old), Geomega (geometry, up-to-date), Cosima (Geant4 simulations, up-to-date).

Bug reports

Bug reports go to: Andreas Zoglauer, "zog (at) ssl (dot) berkeley (dot) edu" - please be specific, provide me with information about what version you are using, let me know how to reproduce the problem, and send me an example!