.. _RelAbund: ************** RelAbund Class ************** .. index:: RelAbund Notebooks ========= .. toctree:: :maxdepth: 1 Simple Examples 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