Starlink Project
Starlink User Note 180.5

Norman Gray
Mark Taylor
Grant Privett

30 September 2008

ESP — Extended Surface Photometry

Version 0.11-4

User’s Manual


ESP (Extended Surface Photometry) is a package of application programs developed to allow you to determine the photometric properties of galaxies and other extended objects.

It has applications that: detect flatfielding faults, remove cosmic rays, median filter images, determine image statistics, determine local background values, perform galaxy profiling, fit 2-D Gaussian profiles to galaxies, generate pie slice cross-sections of galaxies and display profiling results.


1 Introduction
 1.1 An overview
 1.2 What’s new in this release
 1.3 A little more detail
2 Installing ESP
3 Starting up ESP
4 Simple ESP Sessions
 4.1 Getting Help
 4.2 Session 1 — Getting image statistics
 4.3 Session 2 — Interactive profiling by intensity analysis
 4.4 Session 3 — File based profiling by intensity analysis
 4.5 Session 4 — Obtaining galaxy pieslice cross-section
 4.6 Session 5 — Examining profiling results
 4.7 Session 6 — Looking at the image background variation
 4.8 Session 7 — Interactively obtaining 2-D Gaussian source profiles
  4.8.1 GAUFIT: original fitting algorithm
  4.8.2 GAUFIT: least-square fits
5 Deriving accurate background values
 5.1 Global background value determination
 5.2 Local background value determination
6 Removing image contamination
 6.1 Removing consistent image faults
 6.2 Removing other image contamination
7 Removing cosmic rays and bright regions
8 Examining image flatness
9 Highlighting faint diffuse objects
 9.1 Self-correlation
 9.2 Cross-correlation
 9.3 Hybrid cross/self-correlation
10 Obtaining galaxy cross-sections
11 Profiling galaxies using intensity analysis
12 Profiling galaxies using contour analysis
13 Choosing between ELLPRO and ELLFOU
 13.1 Limitations of ELLPRO and ELLFOU
14 Displaying the profiling results
15 Output file formats
16 Incorporating HISTPEAK into your own ADAM applications
17 Acknowledgements
A Alphabetical list of ESP routines.
B Description of the ESP routines
 B.1 Complete routine descriptions
CORR–Performs cross-correlations on an image using a galaxy template
ELLFOU–Ellipse fitting galaxy profiles using contour analysis
ELLPRO–Performs an ellipse fitting galaxy profile using simple intensity analysis
FASTMED–Applies a square median filter of user defined size to an input image
GAUFIT–Performs a 2-D Gaussian fit of multiple sources
GRAPHS–Displays/analyses the results generated using SECTOR, ELLFOU or ELLPRO
HISTPEAK–Establish the mean, mode, median and other statistics for NDF image files
HSUB–A subroutine version of HISTPEAK for developers
LOBACK–Establishes the local mode values for parts of an image
MASK–Uses an ARD file to set some pixels of a given image to bad
MIXUP–To mixup the position of all the pixels in an image
SECTOR–May be used to display the average pixel values within a wedge shaped sector/slice of the image
SELFC–To perform self-correlations on an NDF image file
SELFCW–To perform mixed cross-self-correlations on an NDF image file
SKEW–Generates a skewness representation of the image
TOPPED–Remove all pixel values above a certain limit from an NDF image file

C Bad data masks (ARD)
 C.1 Detailed description of ARD files
D Supported HDS Data Types
E Position angle convention
F Examples of output file formats and glossary
G Backpage alphabetical listing