Surface Brightness Limit Calculator
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pip install sbcontrast==1.0.1
Authors ------- Michael Alan Keim, Pieter van Dokkum, and Jiaxuan Li. Email ----- michael [dot] keim [at] yale [dot] edu Description ----------- The sbcontrast code is a method to obtain surface brightness limits that accurately reflect an images depth at a given spatial scale. Rather than relying on the naive Poisson expectation, this code will estimate limitations presented by large scale variations. A full description of this method is given in Keim et al. 2022 (https://arxiv.org/pdf/2109.09778.pdf). Usage ----- sbcontrast may be run from the command line. Enter 'sbcontrast -h' for help. It requires only an image fits file to run, however users should also specify a fits file containing masks for genuine sources (via -masks), otherwise no masks will be applied and the reported limit will not be as deep as the true value. Note that if the header does not contain the pixel size and photometric zeropoint as expected, the user will need to provide these (via -pix and -zp). Moreover, sbcontrast defaults to a 1sigma, 60 arcsec scale, though other limits may also be specified (via -N and -s). Additional commands (-binmap and -fluctmap) to save the binned image map and the final fluctuation map used to determine the limit are also available. sbcontrast may also be run within python scripts, using numpy arrays rather than fits files. Simply import the sblimit function from sbcontrast. Note that the specified scale may be rounded so that the binning factors are integers. Note also that the accuracy of this limit is limited by data reduction - for scales exceeding that of background subtraction, genuine features above the calculated limit may have been removed. Moreover, at the single pixel scale sbcontrast may diverge from the true rms due to correlations introduced by re-sampling. Citation -------- We ask that users utilizing this tool please cite Keim et al. 2022 (https://arxiv.org/pdf/2109.09778.pdf).