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Fermi Gamma-ray Space Telescope

GBM Software Tools


Prior to the launch of Fermi, the GBM team developed a GUI-based spectral analysis software tool in IDL, called RMfit, specializing in the analysis of GBM trigger data. More than 10 years later, an open source, multi-wavelength approach is desirable, integrating with the long-standing community standard fitting engine, XSPEC. GSpec is a replacement of RMfit, implemented in Python, that allows analysis of GBM data via a user-interactive GUI similar to RMfit and additionally enables users to create their own Python scripts using the included libraries. GSpec provides a seamless interface to XSPEC and allows users to define additional data reduction techniques, such as background fitting/estimation and data binning, as Python-based plugins. It is part of a larger effort to produce a set of GBM data tools to allow the broader community to analyze all aspects of GBM data, including the continuous data that GBM produces.

Note: The current release is a preview release that contains most major functionality. A future v1.0 release will contain complete planned functionality an addition to the GBM Data Tools API.


Note: Rmfit will soon be deprecated in favor of GSpec.

The rmfit software package was developed by members of the gamma-ray astronomy group at the University of Alabama in Huntsville. It uses a forward-folding technique to obtain the best-fit parameters for a chosen model given user-selected source and background time intervals from data files containing observed count rates and a corresponding detector response matrix. rmfit displays lightcurves and spectra using a graphical interface that enables user-defined integrated or time-resolved spectral fits and binning in either time or energy. Originally developed for the analysis of BATSE Gamma-Ray Burst (GRB) spectroscopy, rmfit is a tool for the spectroscopy of transient sources. It has evolved considerably to accommodate the Fermi GBM and LAT data. Limited support is available for data from other instruments such as the Swift BAT. More information is available in the installation notes and accompanying tutorial.

You can install the GBM rmfit tool using the precompiled binary. The system requirements are:

Mac OS X 10.6 (Snow Leopard) to OS X 10.10 (Yosemite)


a machine with Linux or a Linux derivative

GBM Response Generator

The Fermi GBM team has provided a portable version of their response matrix generation software and associated calibration files. You will need about 2.5 GB of disk space to install the package. Previously, this software was available to the public only via an interactive web interface. The response file generator facilitates production of response files for a GBM triggered event or for an arbitrary source location at an arbitrary time for each of the GBM detectors. The intent is to better facilitate studies such as candidate, non-triggered GRBs or solar flares, TGFs and searches for electromagnetic counterparts to gravitational waves. We note that a set of standard, optimally generated, response matrices are archived and available for all triggered events and are recommended for use with those data.