SERVAL (SpEctrum Radial Velocity AnaLyser)

calculate radial velocities from stellar spectra

The concept of SERVAL is described in http://adsabs.harvard.edu/abs/2017A&A...609A..12Z [pdf].

Currently, SERVAL can process data from CARM_VIS, CARM_NIR, ELODIE, ESPRESSO, HARPS, HARPN, and SOPHIE.

Install instruction

Requirements:

• python (2.7 or 3.6+) + numpy, scipy, astropy
• gnuplot (for Mac OS hints are given in the wiki)

Setup the path:

export SERVALHOME=~/mzechmeister
export SERVAL=$SERVALHOME/serval/
export PYTHONPATH=$PYTHONPATH:$SERVALHOME/python/

You can include these lines into your ~/.bashrc. Above is for bash; for tcsh:

setenv SERVALHOME ~
...

Download SERVAL and required tools:

mkdir $SERVALHOME
cd $SERVALHOME
git clone https://github.com/mzechmeister/serval.git
git clone https://github.com/mzechmeister/python.git

Make main files executable:

chmod u+x $SERVAL/src/serval.py
chmod u+x $SERVAL/src/read_spec.py

Install barycorrpy:

pip install --user barycorrpy

See also https://github.com/shbhuk/barycorrpy/wiki/1.-Installation for other possibilities.

Some C and Fortran programs must be compiled:

cd $SERVAL/src/
gcc -c  -Wall -O2 -ansi -pedantic -fPIC polyregression.c; gcc -o polyregression.so -shared polyregression.o
gcc -c  -Wall -O2 -ansi -pedantic -fPIC cbspline.c; gcc -o cbspline.so -shared cbspline.o
python -m numpy.f2py -c -m spl_int spl_int.f
cd $SERVAL/src/BarCor
gfortran bary.f -std=legacy -o bary.e

Newer gfortran version may require an additional option gfortran bary.f -fallow-argument-mismatch -std=legacy -o bary.e. (For problems with Mac OS see wiki.)

A first try to check whether there are any conflicts. It should list all available options:

$SERVAL/src/serval.py --help

(For problems with Mac OS see wiki.)

If you have a ~/bin folder, a useful shortcut is:

ln -s $SERVAL/src/serval.py ~/bin/serval
ln -s $SERVAL/src/srv.py ~/bin/srv

Otherwise, an alias can be created and included in ~/.bashrc.

alias serval=$SERVAL/src/serval.py

and you can run it as

serval --help

SERVAL in action

A basic example is:

mkdir data
(cd data; git clone https://github.com/mzechmeister/HARPS.git)
serval gj699 data/HARPS/gj699/ -inst HARPS -targ gj699

-targ requests the coordinates from simbad (otherwise RA and DEC from fits header is used).

After serval has finished, you can inspect the results with srv.py, for instance

srv gj699 -rv -x

The serval file output is described in src/ReadMe.txt.

Tip

You may want to include the following lines in your ~/.gnuplot:

set colors classic
load "~/mzechmeister/python/zoom.gnu"

In gnuplot 5 this uses the old color scheme from gnuplot 4.

And zoom.gnu gives you some additional features, like pan and zoom with keyboard and arrows keys. In particular, very useful for the look and lookt options to explore the spectra.

Further tips are giving in the wiki.