Kepler CBV Files

The Cotrending Basis Vectors for data release 14, Q0-Q4, are now available for download. The Q0 CBVs may have limited value. Users should read the Data Release 14 Notes for further information.

As data is reprocessed, so will the CBVs. Be sure to use CBVs with the same Data Release number as your data. Below is the current list of available Cotrending Basis Vector (CBV) files. These data products can be used to remove instrumental systematics from the Kepler light curves. There is one FITS file per quarter. Each file contains 84 extensions, one for each CCD channel, and 16 basis vectors per channel. These basis vectors can be fit to the Kepler SAP flux vector and the best fit vectors subtracted to significantly reduce systematic trends in the time series.

To download a particular file, click on the appropriate File Name below. Alternatively, ftp to archive.stsci.edu and cd to /pub/kepler/cbv/ to see and/or download the complete list. Clicking on the linked data release numbers will display the corresponding data release notes.

See the Kepler Archive Manual for a description of the CBV file format, and see Data Release Notes 12 for more information on the CBV characteristics and how to use them.

For a tool to fit and apply CBVs to your Kepler light curve, see keplergo.arc.nasa.gov/ContributedSoftwareKepcotrend.shtml

CBV Files

File Name	Quarter	Data Release	Delivery Date
kplr2009131105131-q00-d14_lcbv.fits	0	14	March 13,2012
kplr2009166043257-q01-d14_lcbv.fits	1	14	March 13, 2012
kplr2009259160929-q02-d14_lcbv.fits	2	14	March 13, 2012
kplr2009350155506-q03-d14_lcbv.fits	3	14	March 13, 2012
kplr2010078095331-q04-d14_lcbv.fits	4	14	March 13, 2012
kplr2010174085026-q05-d08_lcbv.fits	5	8	November 30, 2011
kplr2010265121752-q06-d09_lcbv.fits	6	9	November 30, 2011
kplr2010355172524-q07-d10_lcbv.fits	7	10	November 30, 2011
kplr2011073133259-q08-d11_lcbv.fits	8	11	November 30, 2011
kplr2011177032512-q09-d12_lcbv.fits	9	12	November 30, 2011
kplr2011271113734-q10-d13_lcbv.fits	10	13	December 20, 2011
kplr2012004120508-q11-d15_lcbv.fits	11	15	March 29, 2012

For a small number of mod.outs, the previously delivered Q0-8 cotrending basis vectors (from Jul 27, 2011) included signal from a single noisy or variable star. For example, the third cotrending basis vector in mod.out 4.3 of Q6 contained features that are not true systematics, but instead the imprint of a variable star. Such signals will degrade the quality of your CBV correction.

The CBVs currently available were generated from an ensemble of light curves that have been iteratively cleaned of noisy or variable stars. All future CBVs will be created from an iteratively cleaned ensemble of light curves. While the problem can still occur, it will be rare and will likely only occur in the weaker vectors (> 5).