RadioSource

class dendrocat.RadioSource(hdu, name=None, freq_id=None)

Bases: object

An object to store radio image data.

Parameters:

hdu : PrimaryHDU

An astropy FITS HDU object containing the radio image data and header.

region_id : str, optional

An identifier specifying what sky object the radio image contains.

freq_id : str, optional

An identifier specifying the observation frequency (Ex: 226.0GHz). If not specified, it will be generated from the FITS image header.

Methods Summary

accept(accepted_list)	Accept specific sources in the catalog.
add_sources(*args)	Adds external source entries to the existing catalog.
autoreject([threshold])	Reject noisy detections.
dump(outfile)	Dump the RadioSource object via pickle.
get_pixels(aperture[, catalog, data, …])	Get pixels within an aperture for each entry in the specified catalog.
get_snr([source, background, catalog, data, …])	Return the SNR of all sources in the catalog.
grab(name[, skip_rejects])	Search the catalog for an entry matching a specific name, and return
plot_grid([catalog, data, cutouts, …])	Plot sources in a grid.
reject(rejected_list)	Reject specific sources in the catalog.
reset()	Reset all sources’ rejection flags to 0 (all accepted).
set_metadata()	Sets RadioSource metadata using nu, WCS, and other FITS header data.
to_catalog([dendrogram])	Creates a new position-position catalog of leaves in a dendrogram.
to_dendrogram([min_value, min_delta, …])	Calculates a dendrogram for the image.

Methods Documentation

accept(accepted_list)

Accept specific sources in the catalog.

Parameters:

accpeted_list: list

A list of ``_name``s, for which each corresponding entry will be marked accepted.

add_sources(*args)

Adds external source entries to the existing catalog.

Parameters:

*args: `~astropy.table.Table`

A source catalog containing the sources you wish to add to the existing catalog.

autoreject(threshold=None)

Reject noisy detections.

Parameters:

threshold : float, optional

The signal-to-noise threshold below which sources are rejected

dump(outfile)

Dump the RadioSource object via pickle.

Parameters:

outfile : str

Desired output file path.

get_pixels(aperture, catalog=None, data=None, cutouts=None, save=True)

Get pixels within an aperture for each entry in the specified catalog.

Parameters:

aperture: `~dendrocat.aperture.Aperture`

The aperture determining which pixels to grab.

catalog: `~astropy.table.Table`, optional

A source catalog containing the center positions of each source.

data: array-like

Image data for the sources in the catalog.

cutouts:

For developer use

Returns:

pixels, masks

`~numpy.ndarray`, `~numpy.ndarray`

get_snr(source=None, background=None, catalog=None, data=None, cutouts=None, cutout_data=None, peak=True, save=True)

Return the SNR of all sources in the catalog.

Parameters:

source: array-like

Array of source fluxes to use in SNR calculation.

background: array-like

Array of background fluxes to use in SNR calculation.

catalog: `~astropy.table.Table`

The catalog of sources for which to calculate the SNR.

data: array-like

Image data for the sources in the catalog.

cutouts:

For debugging. Provides a specific set of cutouts instead of letting the function generate them.

cutout_data:

For debugging. Provides a specific set of cutout data instead of letting the function generate it.

peak : bool, optional

Use peak flux of source pixels as ‘signal’. Default is True.

save : bool, optional

If enabled, the snr will be saved as a column in the source catalog and as an instance attribute. Default is True.

Returns:

`~numpy.ndarray`

grab(name, skip_rejects=False)

Search the catalog for an entry matching a specific name, and return

it.

Parameters:

name: tuple, list, or str

The name or names of the sources to search for.

skip_rejects: bool, optional

If enabled, will only search accepted sources.

plot_grid(catalog=None, data=None, cutouts=None, cutout_data=None, source_aperture=None, bkg_aperture=None, skip_rejects=True, outfile=None, figurekwargs={})

Plot sources in a grid.

Parameters:

catalog : astropy.table.Table object, optional

The catalog used to extract source positions.

data : numpy.ndarray, optional

The image data displayed and used to make cutouts.

cutouts : list of astropy.nddata.utils.Cutout2D objects, optional

Image cutout regions to save computation time, if they have already been calculated.

cutout_data : list of numpy.ndarrays, optional

Image cutout region data to save on computation time, if it has already been calculated.

apertures : list of dendrocat.aperture functions, optional

Apertures to plot over the image cutouts.

skip_rejects : bool, optional

If enabled, don’t plot rejected sources. Default is True.

reject(rejected_list)

Reject specific sources in the catalog.

Parameters:

rejected_list: list

A list of ``_name``s, for which each corresponding entry will be marked rejected.

reset()

Reset all sources’ rejection flags to 0 (all accepted).

set_metadata()

Sets RadioSource metadata using nu, WCS, and other FITS header data.

to_catalog(dendrogram=None)

Creates a new position-position catalog of leaves in a dendrogram. This task will overwrite the existing catalog if there is one.

Parameters:

dendrogram : Dendrogram object, optional

The dendrogram object to extract sources from.

Returns:

`~astropy.table.Table`

to_dendrogram(min_value=None, min_delta=None, min_npix=None, save=True)

Calculates a dendrogram for the image.

Parameters:

min_value : float, optional

Minimum detection level to be considered in the dendrogram.

min_delta : float, optional

How significant a dendrogram structure has to be in order to be considered a separate entity.

min_npix : float, optional

Minimum number of pixel needed for a dendrogram structure to be considered a separate entity.

save : bool, optional

If enabled, the resulting dendrogram will be saved as an instance attribute. Default is True.

Returns:

`~astrodendro.dendrogram.Dendrogram` object

A dendrogram object calculated from the radio image.