1 Overview

SPLAT-VO is a graphical tool for displaying, comparing, modifying and analysing astronomical spectra stored in FITS, VOTABLE, TEXT and NDF/NDX format. It can read spectra from local disk files, download them over the Internet, or it can interact with the Virtual Observatory and query servers for spectral data in a region of the sky.

SPLAT-VO can handle many spectra at the same time and will display these as line plots or point markers. Each display window, of which there can be many, can be used to view one or more spectra at the same time. Display windows can be interactively zoomed and scrolled, centred on specific wavelengths, provide continuous coordinate readout, annotated, produce printable hardcopy and be configured in many ways. They also provide the basis for interactive analysis facilities. All of these functions are displayed in a visually rich format, that is intended to appeal especially to casual users of spectral data analysis facilities.

The current set of analysis facilities include background estimation by the fitting of a polynomial to selected parts of a spectrum or by drawing an interpolated spline, the fitting of Gaussian, Lorentzian and Voigt profiles to emission and absorption lines, the filtering of spectra using average, median and line-shape window functions as well as wavelet denoising and the calculation of statistics. A database of laboratory line positions is available to aid in identification.

SPLAT-VO also supports a full range of coordinate systems for spectra, using the latest facilities of the Starlink AST library. This allows coordinates to be displayed and aligned in many different coordinate systems (wavelength, frequency, energy, velocity) and transformed between these and different standards of rest (topocentric, heliocentric, dynamic and kinematic local standards of rest etc.). It also uses AST to transform spectra between various flux systems, so that spectra from a wide variety of sources can be easily compared and used to produce a spectral energy distribution. This is an important feature for supporting the heterogeneous data supplied in the Virtual Observatory.

Finally, SPLAT-VO can interoperate with other VO enabled desktop tools using the SAMP protocol.

If you have any problems with SPLAT-VO then send these to the Starlink user support email list at:


or to the SPLAT-VO mailing-list at:


where hopefully someone can help you.