The IDL/GDL version of FAT is now archived and will not be developed further. Please see https://github.com/PeterKamphuis/pyFAT-astro for a python version that is still in development.
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The Fully Automated TiRiFiC is an IDL/GDL wrapper around the tilted ring fitting code (TiRiFiC) that aims to fully automate the process of fitting simple tilted ring models to line emission cubes. This code is still in the development phase and hence errors and bugs can be present. Nevertheless, the code has extensively been tested and the results and a more extensive description of the code are documented in Kamphuis et al. 2015
The file Current_Status.pdf provides an overview of plots from Kamphuis et al. (2015) which illustrate the performance of the current version of FAT. This fully tested version is available on the master branch. Typically the current version works much better then the version from 2015. However, as we have also reduced the applied errors the plots in this document show that performance is comparable, i.e. the fits are equally accurate with smaller errors. Additionally, as FAT now employs a Monte Carlo method in the regularisation of the parameters the final model can sometimes differ slightly. However this should always be within the calculated errors. If not please open an issue on the GitHub.
For a long time development of FAT has now been done under GDL. As of v2.0.1 accurate performance is no longer guaranteed under IDL, even though there is no reason that GDL code would not run under IDL. As such the recommended way to run now is under GDL. This also means that the installation check does not necessarily work for IDL as small differences can occur between the IDL and GDL runs. When running under IDL and obtaining decent output for the check one can ignore the message that the differences are outside the tolerances. As of the release v2.0 further development of FAT will be done in python (https://github.com/PeterKamphuis/pyFAT)and only bug fixes will be applied to this version.
If you are looking for specific functionality or find that FAT is not performing well despite the galaxy having regular rotation or just want to chat about tilted ring modelling pipelines please do not hesitate to contact me.
It is important to remember that FAT is meant for batch fitting. Hence, the aim of the code is to provide tilted ring models that are accurate for a large fraction of galaxies. Ideally, FAT should identify galaxies that are not fitted well however this feature is not optimal yet. When fitting individual galaxies it is recommended to run FAT and then fine tune the model by hand in TiRiFiC. In most cases such fine tuning will be limited to a few outer rings but in the case of complex galaxies with significant non-cylindrically symmetric motions the models can fail (Or in the case of very bad data but that is not a FAT issue).
FAT is not an automated version of the extended functionality of TiRiFiC. FAT fits simple rotationally symmetric discs with asymmetric warps and surface brightness distributions. However, TiRiFiC itself provides a much more extended functionality and should be used for identifying significant non-cylindrically symmetric motions, thick discs, bars and other such HI features. When modelling such galaxies ideally FAT can provide a base model and setup a .def file with merely a thin disc. These can then be used in TiRiFiC in order to explore large scale motions not captured by FAT’s simple model. For examples of such modelling please see Kamphuis et al. (2011), Zschaechner et al. (2011), Kamphuis et al. (2013), Gentile et al. (2013).
A docker image with FAT can be found here: https://hub.docker.com/r/alankardutta/fat_gdl
If you prefer a local installation please follow the instructions below.
The code requires full installation of:
IDL 7.0 or higher or GDL 0.9.6 or higher with astrolib
TiRiFiC v2.2.3 or higher
SoFiA v 0.4.0 or higher
mpfit package
Standard unix commands pwd, mkdir, rm, cp, ls, python
astrolib (note the Coyote Library Dependencies for newer versions), GDL, IDL,TiRiFiC, SoFiA
IDL/GDL needs to be able to execute tirific, sofia, rename and the standard unix commands from a spawn command. All other dependencies should be in IDL and available with the normal IDL distributions.
To run under GDL you will additionally need the package mpfit for GDL by Ole Streicher (https://packages.debian.org/sid/all/gdl-mpfit/download). Since version 6.0 mpfit is also a requirement when run under idl. The IDL version can be found here: https://cow.physics.wisc.edu/~craigm/idl/fitqa.html#download
The GDL version is tested under Ubuntu 16.04 and runs after running the command
sudo apt-get install gnudatalanguage gdl-astrolib gdl-mpfit libplplot-dev
Under ubuntu the astrolib package and mpfit package were not found after installation and hence a .gdlstartup file is required with the line
!PATH=!PATH+':/usr/share/gnudatalanguage/astrolib:/usr/share/gnudatalanguage/coyote:/usr/share/gnudatalanguage/mpfit'
Unpack the zip file in a desired directory and you are ready to run FAT from this directory under IDL. The rename command might have to be aliased to rename -s, as this depends on which exact rename command and their are many versions available the code excutes the command "rename originalstring replacestring filesonwhichtoexecute" make sure that this is what the rename command does in the shell that is run by IDL.
You will also have to make a softlink in the Support directory to file sofia_pipeline.py in the sofia distribution i.e.:
cd Support/
ln -s pathtosofiainstallation/sofia_pipeline.py sofia_pipeline.py
Where pathtosofiainstallation is the name of the PATH leading to your local installation of SoFiA.
Once you have installed FAT you can check that it has been installed properly by running FAT as
IDL/GDL>.r FAT.pro
IDL/GDL>FAT, /installation_check
This should take typically 10 min and should finish with the message:
!!!!--------------------------------------------!!!!!
!!!! As far as we can tell FAT is installed !!!!!
!!!! properly and runs smoothly. !!!!!
!!!!--------------------------------------------!!!!!
The check consists of fitting a flat disk on NGC 2903. The data for this galaxy were take as part of the WHISP program. This survey is decribed in van der Hulst et al. (2001) and the data can be found at Westerbork on the Web or the WHISP page.
If you get any other message please do not hesitate to file an issue here.
The fit done to check the installation will only leave the .def file and the overview plot that is produced. The directory Installation_Check will contain three overview files. Overview.png is the plot produced by your installation. Overview_IDL.png is for comparison with and IDL run and Overview_GDL.png for comparison with a GDL fit.
The plots should look like this:
Sometimes, due to updates in SoFiA or TiRiFiC, the check might show small difference beyond the tolerance limits. If these are small and you have checked the individual installations of SoFiA, GDL/IDL, TiRiFiC and the Installation Check files are older than the latest SoFiA or TiRiFiC update, then the installation is probably correct and you can continue. Please do post an issue about the outdated installation check.
FAT is currently run under GDL/IDL. It is called as a regular GDL/IDL program, i.e. in GDL/IDL:
IDL/GDL >.r FAT.pro
IDL/GDL >FAT,configuration_file='pathtodir/configfile.config',support='pathtosupportfilesdir'
All information that the code needs about output directories fitting steps and input parameters are taken from the configfile. If a config file is not given it will look for the file 'FAT_INPUT.config' in the directory from which FAT is run. The default support directory is ./Support however you can specify an alternative directory with the keyword support.
A configuration file will require the following parameters:
catalogue=Path_to_catalog_dir/Catalog.txt
The code requires a catalogue with input sources to know which cubes to fit and where they are (See Below) the catalogue keyword should provide the path to this catalogue. There is no default for this.
maindir=Path_to_dir_with_input/
maindir should contain the path where the directories for all galaxies are stored. FAT can produce large amounts of output if requested (e.g. Models for each step, xvdiagrams, Fitting logs, see maps_output parameter). In order to keep this managable each galaxy requires its own directory. There is no default for this parameter.
outputcatalogue=Path/nameofresult.txt
In these three variables Path_to_catalog_dir,Path_to_dir_with_input and Path should be replaced with the local path name to where your input catalog can be found, the path to the directory where the galaxy directories reside and the path to where you want the output catalog to be.
The code will write a summary of the succes of the fit for each galaxy in this file.
new_output='y'
new_ouput controls whether you want a new output catalogue with the summary of the fits done by FAT. If set to 'n' the existing catalogue will be appendended. Typically you would want new output when starting a new batch fit and append if you are restarting a batch fit. Default ='y'
startgalaxy=0
The catalogue number at which the code should start. The default is 0 which is the first line
endgalaxy=-1
The catalogue number at which the code should stop. The default is -1 which means that it should run until the end of the catalog.
outputlog=fitlog.txt
The name of a log file that will trace the iterations and steps that the code is executing for each galaxy. This file is written into the galaxy directory. If left out no log file will be written and additional output will be printed to the terminal.
new_log='y'
Do you want to write a new log file. If set to 'n' the existing log file will be appendended. Default='y'
velocity_resolution=1
The velocity resolution of the data cubes. If set to zero the code assume that the instrumental dispersion is equal to a (1.2 x channel)/(2 x SQRT(2ln2)) otherwise (1+vresolution) x channel/(2 x SQRT(2ln2)). That is, if set to 1 it assumes Hanning smoothing. Default=1.
maps_output = 2
Maps_output controls the amount of outpur created by FAT. 0.= all possible output (This is a lot), 1= all steps model + maps + def files, 2 = Final model + maps + def files for steps + logs, 3 = Only final model def + logs. Default = 2
warp_output = 0
FAT provides the possibility to get information about the fitted warp (Tiltograms, Warp radius, Max angle) if this is required warp_output should be set to 1.
allnew=1.
Parameter for setting the type of input for the initial guesses. possible setting are -1, 0, 1, 2 -1) Start from orginal cube. 0) use initial guesses produced by FAT in a previous run. This is not recommended but can slightly speed up the start of the fitting. However it can lead to mismatches if slight changes have occured between runs.
-
Start from header and blank adjusted cube (i.e _preprocessed) (default)
-
Pre-produced SoFiA output should be used for the initial guesses. These need to be specified in the input catalog (See input catalog)
finishafter=2.
Parameter for finishing the fitting process early. if set to one the program finishes after fitting the flat disk. Default = 2
opt_pixelbeam=4.
The amount of pixels in the FWHM of the minor axis. Default = 4.
A default config file (FAT_INPUT.config) is included in the distribution.
The input catalog should have at least 4 columns named as
number|distance|directoryname|cubename
and seperated by | The number is an easy identifier to keep track of which galaxy is being fitted. the distance is the distance to the galaxy in Mpc. This is used to make some initial guesses for the structure of the galaxy. If it is unknown it should be set to 1. The directory name is the name of the directory of the galaxy to be fitted. This directory should be located in the specified maindir in the config file. cubename is the name of the cube to be fitted. This should be without the fits extension.
An example catalog is included in the distribution. This also gives examples for how to set up a catalog when using pre-made sofia input, i.e. allnew=2
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