Introduction

SExtractor (Source-Extractor) is a program that builds a catalog of objects from an astronomical image. It is particularly oriented towards the reduction of large scale galaxy-survey data, but it also performs well on moderately crowded star fields. Its main features are:

• Support for multi-extension FITS (MEF)
• Speed: up to about 50 Mpixel/s or 10,000 sources/s with a 3 GHz processor
• Ability to work with very large images (up to 2Gx2G pixels on 64 bit machines) thanks to buffered image access
• Real-time filtering of images to improve detectability
• Robust deblending of overlapping extended objects
• Flexible catalog output of desired parameters only
• Pixel-to-pixel photometry in dual-image mode
• Fast and accurate Point-Spread-Function and galaxy model fitting.
• Handling of weight maps and flag maps.
• Optimum handling of images with variable SNR.
• Built-in catalog cross-identification.
• Special mode for photographic scans.
• XML VOTable-compliant catalog output.
• XSLT filter sheet provided for convenient access to metadata from a regular web browser.