# IsophoteList¶

class photutils.isophote.IsophoteList(iso_list)[source]

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 coefficent. a3_err The error associated with a3. a4 A fourth-order harmonic coefficent. a4_err The error associated with a4. b3 A third-order harmonic coefficent. b3_err The error associated with b3. b4 A fourth-order harmonic coefficent. 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) Return the Isophote instance that has the closest semimajor axis length to the input semimajor axis. insert(index, value) Convert an IsophoteList instance to a QTable with the main isophote parameters.

Attributes Documentation

a3

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

a3_err

The error associated with a3.

a4

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

a4_err

The error associated with a4.

b3

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

b3_err

The error associated with b3.

b4

A fourth-order harmonic coefficent. 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

grad_error

grad_r_error

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

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)[source]
extend(value)[source]
get_closest(sma)[source]

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.

insert(index, value)[source]
sort()[source]
to_table()[source]

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

Returns
resultQTable

An astropy QTable with the main isophote parameters.