get_sources

sitelle.source.get_sources(detection_frame, mask=False, sigma=5.0, mode='DAO', fwhm=2.5, threshold=None, npix=4, return_segm_image=False)

Main method used to identify sources in a detection frame and estimate their position. Different modes are available, accesible through the mode keyword :

• DAO : uses the photutils.DAOStarFinder method, adapted from DAOPHOT.
• IRAF : uses the photutils.IRAFStarFinder method, adapted from IRAF.
• PEAK : uses the photutils.find_peaks() method, looking for local peaks above a given threshold.
• ORB : uses the orb.utils.astrometry.detect_stars method, fitting stars in the frame
• SEGM : uses the photutils.detect_sources() method, segmenting the image.

The most reliable is SEGM.

Parameters:

• detection_frame (2D ndarray) – Map on which the sources should be visible.
• mask (2D ndarray or bool, Default = False) – (Optional) If passed, only sources inside the mask are detected.
• sigma (float) – (Optional) Signal to Noise of the detections we want to keep. Only used if threshold is None. In this case, the signal and the noise are computed with sigma-clipping on the deteciton frame. Default = 5
• threshold (float or 2D ndarray of floats) – (Optional) Threshold above which we consider having a detection. Default is None
• mode (str) – (Optional) One of the detection mode listed above. Dafault = ‘DAO’
• fwhm (float) – (Optional) Expected FWHM of the sources. Default : 2.5
• npix (int) – (Optional) Only used by the ‘SEGM’ method : minimum number of connected pixels with flux above the threshold to make a credible source. Default = 4
• return_segm_image (bool, Default = False) – (Optional) Only used in the ‘SEGM’ mode. If True, returns the obtained segmentation image.

Returns:

sources – A DataFrame where each row represents a detection, with at least the positions named as xcentroid, ycentroid (WARNING : using astropy convention). The other columns depend on the mode used.

Return type:

DataFrame