Abstract

 

 

   The fundamental need of GMRT users is to search out the best calibrators for a given observing program. For GMRT observations, the user normally refers to the VLA calibrator database (meant for higher frequency VLA observations) and searches suitable calibrators. We present first results from our efforts to provide a list of suitable low frequency GMRT calibrators.

   

   Here we present, selection criteria and presentation methodology for the first released list of calibrator sources to be used at low frequency GMRT observations, including screen-shot, both image and (u, v) plot for user’s perusal, FITS image, source model (files) for use in AIPS/casapy, etc. at 610 and 235 MHz.

 

 

 

 

Objective

 

 

   Currently phase calibrators are searched from VLA calibrator manual. This manual is meant for high radio frequencies. Since GMRT, operating at low radio frequencies and the low frequency sky is full of point radio sources and the mapped field often contain diffuse radio emission as well, therefore, one requires a good model of the calibrator field along with simple (u, v) range.

   

   To provide a list of suitable low frequency calibrators for GMRT giving detailed information of the calibrators, i.e., auxiliary products.