sep.sum_circle(data, x, y, r, err=None, var=None, mask=None, maskthresh=0.0, segmap=None, seg_id=None, bkgann=None, gain=None, subpix=5)

Sum data in circular aperture(s).


2-d array to be summed.

x, y, rarray_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. These inputs obey numpy broadcasting rules.

err, varfloat or ndarray

Error or variance (specify at most one).

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.

bkganntuple, optional

Length 2 tuple giving the inner and outer radius of a “background annulus”. If supplied, the background is estimated by averaging unmasked pixels in this annulus. If supplied, the inner and outer radii obey numpy broadcasting rules along with x, y and r.

gainfloat, optional

Conversion factor between data array units and poisson counts, used in calculating poisson noise in aperture sum. If None (default), do not add poisson noise.

subpixint, optional

Subpixel sampling factor. If 0, exact overlap is calculated. Default is 5.


The sum of the data array within the aperture.


Error on the sum.


Integer giving flags. (0 if no flags set.)