RelAbund Class¶

Notebooks¶

Overview¶

This class packages the relative abundances of an object, typically an AbsSystem.

Instantation¶

Init¶

One can instantiate via the init and then fill the data dict. This is a bit cumbersome and not especially recommended. But here is an example.

To begin, make a new class instance:

XY = RelAbund()
Loading abundances from Asplund2009

Then load data into the data dict. Here is an example:

XY._data = {6: dict(flag=1, XH=-1., sigXH=0.2, sig=0.05),
         8: dict(flag=2, XH=-1.4, sigXH=0.25, sig=0.05),
         14: dict(flag=1, XH=-1.1, sigXH=0.25, sig=0.05),
         26: dict(flag=1, XH=-1.4, sigXH=0.25, sig=0.05),
         32: dict(flag=3, XH=-0.8, sigXH=0.25, sig=0.05),
         }

The flag value indicate the type of measurement:

Flag	Description
1	Standard value (and error)
2	Lower limit (e.g. saturated line)
3	Upper limit (e.g. blend or non-detection)

Ionic Column Table¶

More frequent usage will be to instantiate using an input table of column density measurements, e.g.:

dla.XY = RelAbund.from_ionclm_table((1,dla.NHI, dla.sig_NHI[0]), dla._ionN)

See pyigm DLA abund Notebook for more.

By Hand¶

For quick and dirty abundance calculations, you may find the from_pair method useful:

Usage¶

You may grab the data for any element with item syntax:

CH = XY[6]
{'flag': 1, 'sig': 0.2, 'val': -1.0}
CH = XY['C']

Element ratios can be accessed by providing a tuple of atomic number or element name:

SiFe = XY['Si', 'Fe']
{'flag': 1, 'sig': 0.070710678118654766, 'val': 0.2999999999999998}

You may generate an astropy Table of the X/Y values:

tbl = XY.table()  # For X/H
tbl = XY.table('Fe')  # For X/Fe

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