source_photometry
- petrofit.segmentation.source_photometry(source, image, segm_deblend, r_list, error=None, cutout_size=None, bg_sub=False, sigma=3.0, sigma_type='clip', method='exact', mask_background=False, plot=False, vmin=0, vmax=None, figsize=[12, 6])[source]
Aperture photometry on a PhotUtils
SourceProperties
.- Parameters:
- source
photutils.segmentation.SourceProperties
SourceProperties
(an entry in aSourceCatalog
)- image2D array
Image to preform photometry on.
- segm_deblend
SegmentationImage
Segmentation map of the image.
- r_listlist
List of aperture radii.
- error2D array
Error image (optional).
- cutout_sizeint
Size of cutout.
- bg_subbool
If the code should subtract the background using the
sigma
provided.- sigmafloat
The sigma value used to determine noise pixels. Once the pixels above this value are masked, a 2D plane is fit to determine the background. The 2D plane model is then converted into an image and subtracted from the cutout of the target source. see the
sigma_type
on how this value will be used.- sigma_type{‘clip’, ‘bound’}, optional
- The meaning of the provided sigma.
'clip'
(default):Uses
astropy.stats.sigma_clipping.sigma_clip
to clip at the providedsigma
std value. Note thatsigma
in this case is the number of stds above the mean.
'bound'
:After computing the mean of the image, clip at
mean - sigma
andmean + sigma
. Note thatsigma
in this case is a value and not the number of stds above the mean.
- method{‘exact’, ‘center’, ‘subpixel’}, optional
The method used to determine the overlap of the aperture on the pixel grid. Not all options are available for all aperture types. Note that the more precise methods are generally slower. The following methods are available:
'exact'
(default): The the exact fractional overlap of the aperture and each pixel is calculated. The returned mask will contain values between 0 and 1.'center'
: A pixel is considered to be entirely in or out of the aperture depending on whether its center is in or out of the aperture. The returned mask will contain values only of 0 (out) and 1 (in).'subpixel'
A pixel is divided into subpixels (see thesubpixels
keyword), each of which are considered to be entirely in or out of the aperture depending on whether its center is in or out of the aperture. Ifsubpixels=1
, this method is equivalent to'center'
. The returned mask will contain values between 0 and 1.
- mask_backgroundbool
Should background pixels, that are not part of any source in the segmentation map, be included? If False, only pixels inside the source’s segmentation are unmasked.
- plotbool
Show plot of cutout and apertures.
- vminint
Min value for plot.
- vmaxint
Max value for plot.
- figsizetuple
Figure size.
- source
- Returns:
- flux_arr, area_arr, error_arr(numpy.array, numpy.array, numpy.array)
Tuple of arrays:
flux_arr
: Photometric sum in aperture.area_arr
: Exact area of aperture.error_arr
: if error map is provided, error of measurements.