Fermi Data Release
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[edit] Data Release
On August 25 2009 the Fermi experiment made their dataset public. Since then I've been working with the LAT data with pointsource objectives in mind, and would like feedback on how to make the Fermi data easier to deal with for other IceCube collaborators interested in using the data for analysis. Send a mail to Mike Baker to get in touch about this.
The plan is to have a top-level directory in the Data Warehouse for
Fermi data. However for now we have the data available in Madison for
monkeying around with. As interfacing with the Fermi data becomes more
developed, this page will me merged into the overall Multiwavelength page.
The all-sky photon-by-photon data is separated by week, currently available in:
/data/ana/Fermi/photon
The exposure information is also split up by week (however, the time covered does not entirely overlap each photon data file):
/data/ana/Fermi/spacecraft
with a merged exposure file for all data so far (SCmerged.fits) in the directory.
I have also extracted the Fermi diffuse-class (high quality) photons into root files.
/data/ana/Fermi/photon_root
You can also find the data at the Fermi ftp site.
[edit] Fermi Software
For your own setup of the Fermi tools, the binary files and instructions can be found here.
If you want to have a quick look, there is a set of the tools currently set up for the cobalt64 machines in Madison, which can be set up in two steps:
export FERMI_DIR=/net/user/mfbaker/Fermi/ScienceTools-v9r15p2-fssc-20090808-x86_64-unknown-linux-gnu-libc2.3.4/x86_64-unknown-linux-gnu-libc2.3.4 source $FERMI_DIR/fermi-init.sh
[edit] Other NASA Tools
NASA's HEAsoft toolset has useful commands to manipulate FITS files, to perform tasks like merging files and editing the headers: [1].
There is also a set of the HEAsoft tools set up for cobalt64 machines, which also can be set up in two setps:
export HEADAS=/net/user/mfbaker/heasoft-6.6.1/x86_64-unknown-linux-gnu-libc2.3.4 . $HEADAS/headas-init.sh
Information on the HEAtools: [2]. Information on more fits tools: [3].
[edit] Examining FITS files
FITS files are the standard data storage for NASA, and are also used for things like CCD images. Like ROOT files, they store the data in binary format. Unlike ROOT files, they also have a plain-text header. This means that you can see what kinds of information columns are in the file with a less command.
I'm sure there are a myriad of ways of looking at fits files, here are a few:
- I think that HippoDraw is a great tool for quickly examining what is in a file, and is available through the I3 Ports system.
- AstroRoot is an extension of the ROOT framework for FITS files. However, I have been able to build with ROOT v5.18.00, but not v5.20.00, and haven't played with it much. Let me know if you've found it to be useful, though!
- For analysis, I will usually default to a brute-force method of dealing with fits files, namely dumping them to a text file and working with that to read in or export to a root file.
[edit] Example Scripts
I have up example scripts:
- Going through from a set RA and dec to a FITS file suitable for making a lightcurve: [4].
- Merging the spacecraft data files to one common file: [5].
- Fermi's Analysis Threads also have some useful walk-thrus.
