Introduction

EVLA early science is provided by two programs for outside users and one for EVLA commissioning staff. All early science programs are peer-reviewed. In keeping with a primary construction project goal, the EVLA will continue to be used for science throughout the commissioning of the telescope into full operations in 2013. Observing during this period thus involves an element of risk associated with the large stepwise increases in throughput bandwidth that are offered to the community at the start of each new array configuration cycle in 2010, 2011, and 2012.

The Open Shared Risk Observing (OSRO) program provides early science capabilities to the general user community. These capabilities initially provided a maximum 256 MHz bandwidth that increased to 2 GHz for the D configuration in mid-2011 and will increase further to 8 GHz at the end of 2012. The Resident Shared Risk Observing (RSRO) program will provide these capabilities, and other more powerful ones, much sooner to users who can reside in Socorro and help with the EVLA commissioning efforts. These same enhanced capabilities will also be made available to EVLA commissioning staff via the EVLA Commissioning Staff Observing (ECSO) program.