Abstract Details
| Name: Shamik Ghosh Affiliation: Indian Institute of Technology, Kanpur Conference ID: ASI2018_1696 Title : Current status of the radio dipole and its measurement strategy with the SKA Authors and Co-Authors : Pankaj Jain, IIT Kanpur Prabhakar Tiwari, Technion, IIT Abstract Type : Contributed Talk Abstract Category : General Relativity and Cosmology Abstract : In the observed galaxy distribution field we expect to find a dipole which can arise from 1. local structures (clustering dipole) and 2. our local motion (kinematic dipole). It is expected that the clustering dipole, which arises from local structure inhomogeneities should saturate when we go to cosmological distance scales of few hundred Mpc. However, recent studies with the 2MASS catalog has shown found that the clustering dipole does not converge by 300 Mpc/h. With the SKA, one would hope to map the clustering dipole and find scales by which it saturates. On the other hand we expect a dipole in the radio galaxy catalog due to our local motion. The measurement of the kinematic dipole by several authors with the NVSS catalog have shown a large excess in the measured value of the kinematic dipole when compared with expectations. It is important to compare performance of various estimators used in this measurement with the aim of developing multiple bias-corrected measurement pipelines for the SKA. We have found in our work that the radio continuum surveys have serious systematics for which they need correction. I will discuss the techniques which are used to study and eliminate such systematics and their limitations. I will also discuss how flux calibration errors will effect systematics corrections. Finally I discuss the preparation strategy we should take for measurement of the the clustering dipole and the kinematic dipole from the SKA using better modelling for systematics of the continuum survey and the foreground contaminants. |