RVLIN CODE

Current version: 2.12 (10 July 2014, rvlin v.2.1): Now handles fixed periods and circular orbits in combination. dvdt now floats if dvdt is specified by default. Lots of phased plotting fixes. Also handles transit time constraints, including for multiple transiting planets. 2.7 contains bug fixes for tp fixing.

The RVLIN package rvlin.tar.gz for IDL is a set of routines that quickly fits an arbitrary number of Keplerian curves to radial velocity data. It can handle data from multiple telescope (i.e. it solves for the offset), constraints on P, e, and time of peri passage, and now can incorporate transit timing data. To use transit information, fix the transit time of planets using the tts= keyword. For multiplanet systems, the length n vector passed to tts will contain the fixed transit time of the first n planets in the system (sorry, no TTVs or uncertainties allowed!).

To install, download the tarball, gunzip it, and read the readme.pro file.

RVLIN is written by Jason Wright and Andrew Howard based on the exploitation of linear parameters in the Kepler problem, discussed here (ApJS..182..205W).

If you use RVLIN or its derivatives in your research, please cite this paper.

Some tips:

  • This uses a nonlinear L-M fitter. Such fitters are not perfect -- they can get pinned at limits (like e=0) and have trouble finding their way out of shallow local minima, even when primed near the correct solution. Try many initial guesses, perhaps different by only a small amount, to be sure you've converged.
  • Uncertainties should not be derived from the variance covarience matrix (there are two here!). We use bootstrapping, driven by RVLIN.

Send questions and comments to jtwright@astro.psu.edu.

By popular demand! Parameter uncertainties with RVLIN:

Sharon (Xuesong) Wang at Penn State has written a robust parameter uncertainty estimator for RVLIN. It is fast and uses bootstrapping, as described in many papers using RVLIN and documentend in Wang et al. (2012, ApJ accepted, arXiv:1210.6985).

The package (for IDL, of course) is available here: boottran_v1.1.tar.gz. Documentation is in bootttran.pro. Enjoy!

Current version is v.1.1 (2 October 2012)

Send questions and comments to cfaxuesong@gmail.com and jtwright@astro.psu.edu.