5 The StarFinder code

The StarFinder code has been provided with a collection of auxiliary routines for data visualization and basic image processing, in order to allow the user to analyze a stellar field, produce an output list of objects and compare different lists, e.g. referred to different observations of the same target. The input image is supposed to be just calibrated.

The code is entirely written in the IDL language and has been tested on Windows and Unix platforms supporting IDL v. 5.0 or later. A widget-based graphical user interface has been created. The main widget appearing on the computer screen is nothing more than an interface to call secondary widget-based applications, in order to perform various operations on the image. The basic documentation about the code can be found in the on-line help pages.

Figure 11: Plot of astrometric errors vs. relative magnitude of detected synthetic stars; the errors are quoted in FWHM units ( $\rm 1~FWHM \sim$ 4 pixel) and represent the distance between the calculated and the true position

Figure 12: Plot of photometric errors vs. relative magnitude of detected synthetic stars. The brightest star in the field has mag = 0 by definition

Figure 13: Luminosity function after adding synthetic stars (continuous line) compared to the mean luminosity function resulting from the analysis of the 10 frames with artificial sources (dashed line); the dotted-dashed line indicates the meanluminosity function of the false detections

IDL users might wish to run interactively the StarFinder routines, without the widget facilities: complete documentation on each module is available for this purpose.