sep.flux_radius

sep.flux_radius(data, x, y, rmax, frac, normflux=None, mask=None, maskthresh=0.0, subpix=5)

Return radius of a circle enclosing requested fraction of total flux.

Parameters:

datandarray

2-d array to be summed.

x, yarray_like

Center coordinates and radius (radii) of aperture(s). x corresponds to the second (“fast”) axis of the input array and y corresponds to the first (“slow”) axis. x, y = (0.0, 0.0) corresponds to the center of the first element of the array. Shapes must match.

rmaxarray_like

Maximum radius to analyze. Used as normalizing flux if normflux is None. Shape must match x and y.

fracarray_like

Requested fraction of light (in range 0 to 1). Can be scalar or array.

normfluxarray_like, optional

Normalizing flux for each position. If not given, the sum within rmax is used as the normalizing flux. If given, shape must match x, y and rmax.

maskndarray, optional

Mask array. If supplied, a given pixel is masked if its value is greater than maskthresh.

maskthreshfloat, optional

Threshold for a pixel to be masked. Default is 0.0.

segmapndarray, optional

Segmentation image with dimensions of data and dtype np.int32. This is an optional input and corresponds to the segmentation map output by extract.

seg_idarray_like, optional

Array of segmentation ids used to mask additional pixels in the image. Dimensions correspond to the dimensions of x and y. The behavior differs depending on whether seg_id is negative or positive. If seg_id is positive, all pixels belonging to other objects are masked. (Pixel j, i is masked if seg[j, i] != seg_id and seg[j, i] != 0). If seg_id is negative, all pixels other than those belonging to the object of interest are masked. (Pixel j, i is masked if seg[j, i] != -seg_id). NB: must be included if segmap is provided.

subpixint, optional

Subpixel sampling factor. Default is 5.

Returns:

radiusndarray

The sum of the data array within the aperture(s). Shape is same as x, except if frac is an array; then the dimension of frac will be appended. For example, if x and frac are both 1-d arrays, the result will be a 2-d array with the trailing dimension corresponding to frac.

flagsndarray

Integer giving flags. Same shape as x. (0 if no flags set.)