Durham:Physics:JRM

Despite there being some wonderful software resources available to the astronomy community (the excellent STSDAS , IDL ASTROLIB and Coyote's IDL helppages spring instantly to mind), like all astronomy students, I've had to produce my own software packages to assist my data analysis (generally built up using code from the above resources!). Below, you'll find downloads to some of the packages I've created, and think other people may find useful.

I choose to programme in IDL code. I have found that it is easy to script, and there are lots of useful built-in processes and functions that speed up programming and reduce running times. As it is the language of choice for many other astronomers, there is also a wealth of astronomy related IDL tips on the web. However, I've tried to mainly produce GUI based packages, so an in depth knowledge of IDL should not be required.

Before downloading and running any of the below scripts, you should already have a copy of all the IDL Astrolib packages within the IDL search path (UNIX tarball available here).

Note: Each of the following tarballs contains an ASCII instruction manual for the procedure. I'm still working on these packages, and will welcome any suggestions or reports of bugs. Feel free to edit any packages to meet your (or the wider community's) needs. If you send me a copy, I'll put them here with acknowledgements. I don't admit to being an IDL master. The packages should be used with caution. Remember, I am but a lowly postgrad student, trust your own eyes and instincts before trusting anything here!

1. SPANALYSE

A GUI that can be used to quickly analyse spectra. Features include:

In order that this package can be used with a wide range of spectra file formats, it must be accompanied with an IDL script that extracts the data from the file and converts it into a format that the package can recognise. Thus, a little bit of knowledge of IDL is required to use this package. As a guide, I have included some of my own extraction scripts in the tarball.

Note: Requires TeXtoIDL

Many AGN display strong FeII emission lines that often mask other spectral features. This package uses the procedure outlined in Boroson & Green (1992) with the FeII line lists of Veron-Cètty et al. (2004) to interactively remove the FeII lines from AGN spectra.

The red-end of the optical spectrum (i.e. beyond ~690nm) suffers from telluric absorption features due to the earth's atmosphere. If, during your observing run, you observe objects with 'well known spectra' (i.e. calibration stars), then you can determine the strength of these absorption features and remove themfrom your science spectra. There are procedures in IRAF that can be used to do this, but I found them very difficult to use. Therefore, for the spectra I took using the WHT, I wrote my own telluric removal GUI, based on some software I obtained from the near-Infrared telescope, IRTF.

4. KRISIS
Kwik-Reduce ISIS (Sorry!!)

IDL-based ISIS reduction script.

This script will take the raw data files produced by ISIS on the WHT and perform all the necessary steps to produce an extracted, wavelength and flux calibrated object spectrum. Data from both the Red and Blue arms are reduced simultaneously, the appropriate calibration files are used for each. All that must be done prior to running this script is place all the raw data files into the required directories:

This is basically a move away from using IRAF to reduce long slit data. It obviously hasn't been tested as well as IRAF, and should therefore be treated with caution. I hope that people will use it to quickly (and less painfully!) reduce ISIS spectra.

Although very good at what it does, the SDSS spectral fitting pipeline only fits the emission lines with a single Gaussian, no matter how complicated the emission line may be. The emission lines of AGN tend to have broad and narrow components, so need more complex modelling. I am currently working with collaborators at Durham University to create a new SDSS line fitting routine that will fit multiple components using a step-by-step chi-squared minimisation routine. This work is just about complete, but we're still working on publishing the results. Once the results are published, I'll release this software. Contact me if you'd like to use it sooner.

An easy-to-use program that I wrote to assist in a project that I am currently working on with a Masters student at Durham University. It is intended to be used as a quick and easy way to extract line flux measurements of a set of pre-determined emission lines in a large number (~100) SDSS spectra. We didn't want to automate the process, as some of the emission lines in which we are interested are weak and simple fitting routines wouldn't work well. This is unlikely to be as useful as other software here, but you are free to hack it if you could use something similar.

A nice little script that will produce a finder chart that is good enough to submit for a queue observation. Tell it the ra and dec of your object (degrees or sexigesimal) and it will center the image around it. Mark your object with a cross or surround it with a rectangle or circle of any size. You can even change the orientation of your rectangle! Put a scale on your image and adjust the contrast ratio. Don't want to fuss around with downloading your own image?? Then let makefinder query the DSS database for you using either a set of coordinates or a NED resolvable name.

An modified version of plothist (from the IDL astrolibrary). By adding the /ROTATE keyword when calling this routine, the histogram is plotted on its side with bars extending from left to right. All other plothist functions are preserved and can be implemented in the sideways plots.

Durham:Physics:JRM

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