VLA/JVLA monitoring of bright northern radio sources^⋆

¹ Tufts University, Medford, MA, 02155 USA
e-mail: anna.sajina@tufts.edu
² Haverford College, Haverford, PA 19041, USA
³ National Radio Astronomy Observatory, Sorocco, NM 87891, USA
⁴ Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
⁵ Instituto de Física de Cantabria (CSIC-Universidad de Cantabria), Avda. los Castros s/n, 39005 Santander, Spain

Received: 20 June 2012
Accepted: 13 November 2012

Abstract

We report multiple epoch VLA/JVLA observations of 89 northern hemisphere sources, most with 37 GHz flux density  >1 Jy, observed at 4.8, 8.5, 33.5, and 43.3 GHz. The high frequency selection leads to a predominantly flat spectrum sample, with 85% of our sources being in the Planck Early Release Compact Source Catalog (ERCSC). These observations allow us to: 1) validate Planck’s 30 and 44 GHz flux density scale; 2) extend the radio spectral energy distributions of Planck sources to lower frequencies allowing for the full 5−857 GHz regime to be studied; and 3) characterize the variability of these sources. At 30 GHz and 44 GHz, the JVLA and Planck flux densities agree to within  ~3%. On timescales of less than two months the median variability of our sources is 2%. On timescales of about a year the median variability increases to 14%. Using the WMAP 7-year data, the 30 GHz median variability on a 1−6 years timescale is 16%.