Open AccessA two‐dimensional Kolmogorov–Smirnov test for crowded field source detection: ROSAT sources in NGC 6397
Author(s) -
Metchev S. A.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05595.x
Subject(s) - physics , rosat , astrophysics , globular cluster , core (optical fiber) , field (mathematics) , cluster (spacecraft) , optics , galaxy , mathematics , computer science , pure mathematics , programming language
We present a two‐dimensional version of the classical one‐dimensional Kolmogorov–Smirnov (KS) test, extending an earlier idea due to Peacock and an implementation proposed by Fasano and Franceschini. The two‐dimensional KS test is used to optimize the goodness of fit in an iterative source‐detection scheme for astronomical images. The method is applied to a ROSAT /HRI X‐ray image of the post‐core‐collapse globular cluster NGC 6397 to determine the most probable source distribution in the cluster core. Comparisons to other widely used source‐detection methods, and to a Chandra image of the same field, show that our iteration scheme is superior in measuring statistics‐limited sources in severely crowded fields.