The MasterCatalog Class

A MasterCatalog object combines multiple RadioSource objects, retaining each object’s attributes while creating a new, combined catalog from the sources contained in their individual catalogs.

The MasterCatalog enables analysis not possible with a single RadioSource object, such as photometry and catalog cross-matching.

Adding Objects

Additional RadioSource or MasterCatalog objects can be added to an existing MasterCatalog using add_objects.

from dendrocat import RadioSource, MasterCatalog
from dendrocat.utils import match
from import fits

source_object1 = RadioSource('file1.fits'), name='so1')
source_object2 = RadioSource('file2.fits'), name='so2')
source_object3 = RadioSource('file3.fits'), name='so3')

If source_object3 is a much lower-resolution image, you may want to forgo generating a dendrogram for it. The source regions from the other two higher-resolution images may be used instead.


mastercatalog = match(source_object1, source_object2)

Adding other RadioSource objects or MasterCatalog objects will preserve the existing MasterCatalog’s source catalog.

>>> mastercatalog.add_objects(source_object3)
>>> mastercatalog.__dict__.keys()
dict_keys(['catalog', 'accepted', 'so1', 'so2', 'so3'])

At this point, performing photometry yields photometry data for all three images, though only two images were used to detect the sources in the first place.

Note that the MasterCatalog which calls add_objects will always have its catalog preserved, and will take RadioSource objects from whatever is added to it.

>>> mastercatalog1 = MasterCatalog(so1, so2, catalog=cat_A)
>>> mastercatalog2 = MasterCatalog(so3, so4, catalog=cat_B)
>>> mastercatalog1.add_objects(mastercatalog2)
>>> mastercatalog1.catalog == cat_A

>>> mastercatalog1.__dict__.keys()
dict_keys(['catalog', 'accepted', 'so1', 'so2', 'so3', 'so4'])

Renaming Sources

Any source can have its _name set for distinguishability. Suppose we have a MasterCatalog object named mc.

#Index of the row in the source catalog containing the old name
index_of_old_name = [mc.catalog['_name'] == '226007']

# Assign new name to the row
mc.catalog['_name'][index_of_old_name] = 'w51d2'

This can also be done in one line.

>>> mc.catalog['_name'][mc.catalog['_name'] == '226007'] = 'w51d2'

Here, we first access the _name column of the catalog. Then, we index the column with the location in the catalog the _name is equal to the old name, '226007'. Then the entry in the catalog is set to be equal to 'w51d2'