How do you analyse hundreds of spectra lines in a convenient way? Try the VWA package.
What can VWA
do?
VWA will help you analyse your normalized stellar spectrum with a certain
degree of manual interaction.
How does VWA
work?
(1)
vwaview: selection of lines.
(2) vwatask: iterative fit of abundances.
(3) vwaexam: check the
fitted lines.
(4) vwares: compare results for different models or different spectra.
The VWA
software package is written in IDL. Thus, you will also need an IDL
licence to run the software. A few Fortran and C-programs also need to be compiled.
The name VWA
is the abbreviation of v sin i, wavelength shift,
abundance analysis
NEWS
2009-14-06 VWA has a new logo - June 2009 Ok,
it's not entirely legal in terms of copyrights. I would like to thank
ESO and Nike for making their cool graphics available on the internet.In other news... Two people have independently downloaded VWA and managed to get it running without any help from me. I take this as a hint that the installation manual is fairly good at this point.
2009-22-05 A new VWA update - May 2009 I have included some new features in vwaview.Go to downloads to get the latest version.
2008-23-11 Renormalization of spectra with VWA - Nov. 2008 A
well-known problem for everyone who has been working with echelle
spectra is the poor normalization that usually comes out of the
reduction pipeline. I have now included the widget program rainbow, which I have found very useful when normalizing by own spectra from FEROS, UVES or HARPS. The rainbow package can be downloaded as a part of VWA from the download page.
Right-click on the image above and select "display image" to see a screenshot from rainbow.
2008-29-10 MARCS models now work with VWA I have included a grid of models from the new grid of MARCS models
that use the revised Solar abundances from Grevesse, Asplund &
Sauval (2007). These models are now part of the VWA distribution. When
you use these models please give reference to Gustafsson et al. 2008 (A&A
486, 951). Note that these MARCS models are now used by default in VWA,
although the ATLAS9 models can of course still be used (only option for stars hotter than 8000 K).
2008-06-05 Major update of VWA - May 2008 The
VWA programs and the manual have had a major overhaul. The
software should be easier to install. The manual has been updated.
Right-click on the image above and select "display image" to see a screenshot from vwaview.
2007-04-03 Programs and Manual
updated for 2007 The yearly update of VWA programs has
been completed. The manual has been expanded and now covers the
analysis of binary stars.
2006-01-12 VWA joins the VSOP
project The VSOP
project collects spectra of interesting variable and peculiar
stars. VWA will be used to determine fundamental parameters and
abundances in the VSOP targets.
2006-26-01 Programs and Manual
updated
The
manual was finally updated with much more elaborate instructions on how
to install the code on your system. I included descriptions on how to
make log-gf correction files. A brief description of how to analyse
double-lined binary stars also included. Some of the core VWA programs have been updated.
2006-25-01 Comparison of ATLAS9
/ MARCS models
To use
MARCS models with VWA you need to change the format of the MARCS
atmosphere model files to that of Kurucz ".krz" files. I have made
comparisons for the Fe1/Fe2 ionization balance found in a
high-resolution and high-S/N spectrum of the Sun when using an
interpolated Heiter et al. (2002) model (modified ALTAS9) and a MARCS
model (provided by U.J. Graae). The difference between the mean Fe1/Fe2
abundances is 0.14 dex for the modified Kurucz ATLAS9 model but only
0.06 dex for the MARCS model. There is still a significant (positive)
correlation of Fe1 abundances and excitation potentials.
2005-17-07 VWA can
now handle binary stars
I have expanded VWA to do abundance analysis of binary stars. You need
to specify the luminosity ratio (e.g. based on the relative radii and
theoretical Planck functions) and
the relative radial velocities of the components. The documentation for
working with binary stars has not been written yet.
The figure below is from automatic fitting with VWA: The crosses mark
the observed spectrum of the binary WZ Oph from FEROS. The fitted Cu at
5505.5 Angstrom line is marked. The dashed line is the synthetic
spectrum of the secondary star and the dash-dotted line is for the
primary star. The combined spectrum is the solid line. The flux ratio
of the binary is close to 1.0
2005-18-04 VWA updated
The official installation and user guide is now available. In addition,
several minor bug fixes.
2004-14-04 VWA is
available for download
After three years of development an interactive version of VWA
is available.
Download
VWA. 
