Loading Data

Takahe’s loader attempts to infer the right headers by sniffing the filename. As such, to receive the best benefits of using the loader, your files should conform to a certain filename structure.

Firstly, Takahe splits filenames based on the underscore character _. We call each part a “field” of the filename. If it sniffs a field beginning with the letter z, Takahe assumes that this field designates the metallicity of the sample.

If Takahe detects “StandardJJ” in the filename, it presumes you are using J.J. Eldridge’s StandardJJ structure, where the file is structured as follows:

m1 m2 a0 e0 weight evolution_age rejuvenation_age

You cannot currently override the metallicity detection, but you can override the inference on the fields – pass the dictionary name_hints to the loader. Passing this will always override the inference.

Finally, if there is a field _ct in the filename, Takahe assumes the final field is the coalescence time of the system.

On Metallicity

It’s worth mentioning that Takahe, like BPASS, assumes that solar metallicity is 0.020, and generally measures metallicity as relative to this. So Z = 0.010 represents half-solar metallicity. The metallicity field in the filename can be understood as:

  Z \(Z/Z_\odot\)
zem5 0.00001 0.0005
zem4 0.0001 0.005
z001 0.001 0.05
z002 0.002 0.10
z003 0.003 0.15
z004 0.004 0.20
z006 0.006 0.30
z008 0.008 0.40
z010 0.010 0.50
z014 0.014 0.70
z020 0.020 1.00
z030 0.030 1.50
z040 0.040 2.00

Let’s examine how Takahe analyses the file data/Remnant-Birth-bin-imf135_300-z001_StandardJJ_ct.dat:

  1. We strip the file extension and containing directories: Remnant-Birth-bin-imf135_300-z001_StandardJJ_ct
  2. We split the file from the right based on _: Remnant-Birth-bin-imf135_300-z001_StandardJJ, ct
  3. We split the first part of the filename based on -: Remnant, Birth, bin, imf135_300, z001_StandardJJ, ct
  4. We check each field and identify relevant parts: z001, StandardJJ, ct.
  5. We confirm that this represents a 5% solar metallicity file, with headers as given by the StandardJJ prescription, containing coalescence times for the ensemble.

Naming Convention

Takahe employs a naming convention for data files. In future this will be customisable, but for now it is not.

Files in a data directory must be named according to the convention Remnant-Birth-bin-imf135_300-z020_StandardJJ.dat. Optionally, one may suffix this with .gz, and one may customise the metallicity away from z020. One may also add _ct after StandardJJ to indicate the presence of an eigth column indicating the coalescence time.