CARMA MEMO 59

Monitoring of Secondary Calibrator Fluxes at CARMA

Amber Bauermeister, Statia Cook, Chat Hull (UCB), Woojin Kwon (UIUC), 
Tom Plagge (U Chicago)

A record of historical secondary calibrator fluxes is maintained at CARMA
throug h two types of monitoring: through dedicated flux calibration
(fluxcal) tracks a nd by extracting calibrator fluxes from science
tracks. In this memo, we describ e how each of these is carried out,
emphasizing the changes implemented in flux monitoring using science
tracks in May 2012.  We briefly review the causes of va riation in the
measurements of secondary calibrator fluxes: both the intrinsic v ariability
in the flux of calibration sources (the motivation for flux monitorin g)
as well as system-induced variations. We also present an overview of how
the historical fluxes may be accessed by a CARMA user and how this record
of fluxes should be used in the calibration of a science dataset.