This tool is designed for quickly identifying which elements (or more specifically which ions) are present in a spectrum.
- Usual data-analysis modules (numpy, scipy, matplotlib)
- mh.spectra -- another repo of mine for working with astrophysical spectra
Basic usage looks like
element_spec spectrum.dat FeI 7500 1
- Arg1: The filename containing the spectrum you are working with.
- Arg2: Ion name
- Arg3: Effective temperature in Kelvin
- Arg4: Abundance in arbitrary units, 1.0 is good starting point for most metals
Other options exist depending what you want to do. For instance, if your spectrum is redshifed by 50km/s, you can use
element_spec spectrum.dat FeI 7500 1 -rv=50
If you think a model looks like a good approximation, you can save it for next time
element_spec spectrum.dat FeI 7500 1 -rv=50 --write
This model will be saved in the current directory, and plotted in blue next time. Multiple models will be combined together, so you can keep track of all lines that you've identified.
Description of other options can be found with
element_spec --help
A good strategy is to start with the most obvious ions, e.g. HI or CaII, and use that to establish the RV, writing the model to disk when you're done. Then work through the next most common ions in your spectrum to mark off the more obvious lines. In the case of D(A)Z white dwarfs this might be Ca, Mg, Fe, and Si where depending on the temperature, neutral and/or first singly ionised lines should be checked. Then the more exotic ions (such as TiI/II, SrII etc) can be checked against the remaining unidentified lines.