Abstract Details
| Name: Arnab Chakraborty Affiliation: IIT, Indore Conference ID: ASI2019_81 Title : Detailed study of the ELAIS N1 field with the uGMRT - I. Characterizing the 325 MHz foreground for redshifted 21 cm observation Authors and Co-Authors : Arnab Chakraborty and Abhirup Datta, Samir Choudhuri, Nirupam Roy, Huib Intema, Madhurima Choudhury, Somnath Bharadwaj Abstract Type : Poster Abstract Category : Extragalactic Astronomy Abstract : The major challenge for detecting the redshifted 21-cm signal of neutral hydrogen from Cosmic Dawn, Epoch of Reionization (EoR) and post-reionization epoch is to mitigate the bright Galactic and extragalactic foregrounds. Here, we present initial results of newly upgraded Giant Meterwave Radio Telescope (uGMRT) observation of European Large-Area ISO Survey-North 1 (ELAIS-N1) at 350 MHz. This is the first paper of this series, where we present only recent observation of ELAIS-N1 with 32 MHz bandwidth. In later papers, we will present results from the entire bandwidth of observations of 200 MHz of the same field. We have calibrated the data with and without direction-dependent calibration techniques. We present detailed comparison between these two approaches. We have found that DGSE dominates the sky, after point source subtraction, across the angular multipole range 1115 < l < 5083 and 1565 < l < 4754 for direction-dependent and -independent calibrated visibilities respectively. The statistical fluctuations in diffuse Galactic synchrotron emission (DGSE) has been quantified as a power law. The best fitted values of amplitude and power law index are (62 +/-6 mK^2, 2.55 +/- 0.3) and (48 +/- 4 mK^2, 2.28 +/- 0.4) for these two different calibration approaches. We have also shown that higher tapering of sky response is required to suppress the effect of bright sources for direction-independent calibration technique in comparison with direction-dependent one. For both the cases the slope is consistent with the previous measurements of DGSE in other parts of sky. |