IsophoteList

class photutils.isophote.IsophoteList(iso_list)

Bases: object

Container class that provides the same attributes as the Isophote class, but for a list of isophotes.

The attributes of this class are arrays representing the values of the attributes for the entire list of Isophote instances. See the Isophote class for a description of the attributes.

The class extends the list functionality, thus provides basic list behavior such as slicing, appending, and support for ‘+’ and ‘+=’ operators.

Parameters:

iso_listlist of Isophote

A list of Isophote instances.

Attributes Summary

a3	A third-order harmonic coefficient.
a3_err	The error associated with a3.
a4	A fourth-order harmonic coefficient.
a4_err	The error associated with a4.
b3	A third-order harmonic coefficient.
b3_err	The error associated with b3.
b4	A fourth-order harmonic coefficient.
b4_err	The error associated with b3.
ellip_err	The ellipticity error.
eps	The ellipticity of the ellipse.
grad	The local radial intensity gradient.
grad_error	The measurement error of the local radial intensity gradient.
grad_r_error	The relative error of local radial intensity gradient.
int_err	The error of the mean intensity (rms / sqrt(# data points)).
intens	The mean intensity value along the elliptical path.
ndata	The number of extracted data points.
nflag	The number of discarded data points.
niter	The number of iterations used to fit the isophote.
npix_c	The total number of valid pixels inside a circle with the same sma as the ellipse.
npix_e	The total number of valid pixels inside the ellipse.
pa	The position angle (radians) of the ellipse.
pa_err	The position angle error (radians).
pix_stddev	The estimate of pixel standard deviation (rms * sqrt(average sector integration area)).
rms	The root-mean-square of intensity values along the elliptical path.
sample	The isophote EllipseSample information.
sarea	The average sector area on the isophote (pixel**2).
sma	The semimajor axis length (pixels).
stop_code	The fitting stop code.
tflux_c	The sum of all pixels inside a circle with the same sma as the ellipse.
tflux_e	The sum of all pixels inside the ellipse.
valid	The status of the fitting operation.
x0	The center x coordinate (pixel).
x0_err	The error associated with the center x coordinate.
y0	The center y coordinate (pixel).
y0_err	The error associated with the center y coordinate.

Methods Summary

append(value)
extend(value)
get_closest(sma)	Return the Isophote instance that has the closest semimajor axis length to the input semimajor axis.
get_names()	Print the names of the properties of an IsophoteList instance.
insert(index, value)
sort()
to_table([columns])	Convert an IsophoteList instance to a QTable with the main isophote parameters.

Attributes Documentation

a3

A third-order harmonic coefficient. See the fit_upper_harmonic() function for details.

a3_err

The error associated with a3.

a4

A fourth-order harmonic coefficient. See the fit_upper_harmonic() function for details.

a4_err

The error associated with a4.

b3

A third-order harmonic coefficient. See the fit_upper_harmonic() function for details.

b3_err

The error associated with b3.

b4

A fourth-order harmonic coefficient. See the fit_upper_harmonic() function for details.

b4_err

The error associated with b3.

ellip_err

The ellipticity error.

eps

The ellipticity of the ellipse.

grad

The local radial intensity gradient.

grad_error

The measurement error of the local radial intensity gradient.

grad_r_error

The relative error of local radial intensity gradient.

int_err

The error of the mean intensity (rms / sqrt(# data points)).

intens

The mean intensity value along the elliptical path.

ndata

The number of extracted data points.

nflag

The number of discarded data points. Data points can be discarded either because they are physically outside the image frame boundaries, because they were rejected by sigma-clipping, or they are masked.

niter

The number of iterations used to fit the isophote.

npix_c

The total number of valid pixels inside a circle with the same sma as the ellipse.

npix_e

The total number of valid pixels inside the ellipse.

pa

The position angle (radians) of the ellipse.

pa_err

The position angle error (radians).

pix_stddev

The estimate of pixel standard deviation (rms * sqrt(average sector integration area)).

rms

The root-mean-square of intensity values along the elliptical path.

sample

The isophote EllipseSample information.

sarea

The average sector area on the isophote (pixel**2).

sma

The semimajor axis length (pixels).

stop_code

The fitting stop code.

tflux_c

The sum of all pixels inside a circle with the same sma as the ellipse.

tflux_e

The sum of all pixels inside the ellipse.

valid

The status of the fitting operation.

x0

The center x coordinate (pixel).

x0_err

The error associated with the center x coordinate.

y0

The center y coordinate (pixel).

y0_err

The error associated with the center y coordinate.

Methods Documentation

append(value)

extend(value)

get_closest(sma)

Return the Isophote instance that has the closest semimajor axis length to the input semimajor axis.

Parameters:

smafloat

The semimajor axis length.

Returns:

isophoteIsophote instance

The isophote with the closest semimajor axis value.

get_names()

Print the names of the properties of an IsophoteList instance.

insert(index, value)

sort()

to_table(columns='main')

Convert an IsophoteList instance to a QTable with the main isophote parameters.

Parameters:

columnslist of str

A list of properties to export from the isophote list. If columns is ‘all’ or ‘main’, it will pick all or few of the main properties.

Returns:

resultQTable

An astropy QTable with the main isophote parameters.