# bunch¶

class ChiantiPy.core.bunch(temperature, eDensity, wvlRange, elementList=None, ionList=None, minAbund=None, keepIons=0, em=None, abundanceName=None, verbose=0, allLines=1)[source] [edit on github]

Calculate the emission line spectrum as a function of temperature and density.

‘bunch’ is very similar to ‘spectrum’ except that continuum is not calculated and the spectrum is not convolved over a filter. However, this can be done with the inherited convolve method

one of the convenient things is that all of the instantiated ion classes, determined through such keywords as ‘elementList’, ‘ionList’, and ‘minAbund’ are kept in a dictionary self.IonInstances where self.IonInstances[‘mg_7’] is the class instance of ChiantiPy.core.ion for ‘mg_7’. All its methods and attributes are available.

includes elemental abundances and ionization equilibria

the set of abundances, a file in \$XUVTOP/abundance, can be set with the keyword argument ‘abundanceName’

temperature and density can be arrays but, unless the size of either is one (1), the two must have the same size

Inherited methods include ‘intensityList’, ‘intensityRatio’ (between lines of different ions), and ‘intensityRatioSave’ and ‘convolve’.

A selection of elements can be make with elementList a list containing the names of elements that are desired to be included, e.g., [‘fe’,’ni’]

A selection of ions can be make with ionList containing the names of the desired lines in Chianti notation, i.e. C VI = c_6

Both elementList and ionList can not be specified at the same time

a minimum abundance can be specified so that the calculation can be speeded up by excluding elements with a low abundance. With solar photospheric abundances -

setting minAbund = 1.e-4 will include H, He, C, O, Ne setting minAbund = 2.e-5 adds N, Mg, Si, S, Fe setting minAbund = 1.e-6 adds Na, Al, Ar, Ca, Ni

At least one of elementList, ionList, or minAbund must be set in order for ‘bunch’ to include any ions.

Setting em will multiply the spectrum at each temperature by the value of em.

em [for emission measure], can be a float or an array of the same length as the temperature/density