| Name: | Suman Chatterjee |
| Affiliation: | National Center for Raido Astrophysics, Pune |
| Conference ID : | ASI2023_347 |
| Title : | The Tracking Tapered Gridded Estimator (TTGE) for the power spectrum from drift scan observations |
| Authors : | Suman Chatterjee, Somnath Bharadwaj, Samir Choudhuri, Shiv Sethi and Akash Kumar Patwa |
| Mode of Presentation: | Oral |
| Abstract Category : | General Relativity and Cosmology |
| Abstract : | Intensity mapping with the redshifted 21-cm line is an emerging tool in cosmology.
Drift scan observations, where the antennas are fixed to the ground and the telescope's pointing center (PC) changes continuously on the sky due to earth's rotation, provide broad sky coverage and sustained instrumental stability needed for 21-cm intensity mapping. In this talk, I intend to present the Tracking Tapered Grided Estimator (TTGE) to quantify the power spectrum of the sky signal estimated directly from the visibilities measured in drift scan radio interferometric observations. The TTGE uses the data from the different PC to estimate the power spectrum of the signal from a small angular region located around a fixed tracking center (TC). The size of this angular region is decided by a suitably chosen tapering window function which serves to reduce the foreground contamination from bright sources located at large angles from the TC. It is possible to cover the angular footprint of the drift scan observations using multiple TC, and combine the estimated power spectra to increase the signal to noise ratio. We have validated the TTGE using simulations of $154 \, {\rm MHz}$ MWA drift scan observations. I shall show that the TTGE can recover the input model angular power spectrum $\cl$ within $20 \%$ accuracy over the $\ell$ range $40 < \ell < 700$. |
