Simulated foreground predictions for HI at z = 3.35 with the Ooty Wide Field Array: I. Instrument and the foregrounds
arXiv:1707.05335 · doi:10.1093/mnras/stx1796
Abstract
Foreground removal is the most important step in detecting the large-scale redshifted HI 21-cm signal. Modelling foreground spectra is challenging and is further complicated by the chromatic response of the telescope. We present a multi-frequency angular power spectrum (MAPS) estimator for use in a survey for redshifted HI 21-cm emission from z~3.35, and demonstrate its ability to accurately characterize the foregrounds. This survey will be carried out with the two wide-field interferometer modes of the upgraded Ooty Radio Telescope, called the Ooty Wide Field Array (OWFA), at 326.5 MHz. We have tailored the two-visibility correlation for OWFA to estimate the MAPS and test it with simulated foregrounds. In the process, we describe a software model that encodes the geometry and the details of the telescope, and simulates a realistic model for the bright radio sky. This article presents simulations which include the full chromatic response of the telescope, in addition to the frequency dependence intrinsic to the foregrounds. We find that the visibility correlation MAPS estimator recovers the input angular power spectrum accurately, and that the instrument response to the foregrounds dominates the systematic errors in the recovered foreground power spectra.
16 pages, 13 figures, 1 table. Accepted for publication in MNRAS
References in corpus (30)
- Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
- Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy
- Late-time cosmology with 21cm intensity mapping experiments
- The Epoch of Reionization Window: I. Mathematical Formalism
- Foreground simulations for the LOFAR - Epoch of Reionization Experiment
- Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder
- Possibility of Precise Measurement of the Cosmological Power Spectrum With a Dedicated 21cm Survey After Reionization
- On using visibility correlations to probe the HI distribution from the dark ages to the present epoch I: Formalism and the expected signal
- The Deep SWIRE Field I. 20cm Continuum Radio Observations: A Crowded Sky
- An Improved Method for 21cm Foreground Removal
- Foregrounds for redshifted 21 cm studies of reionization: GMRT 153 MHz observations
- Spectral Index of the Diffuse Radio Background Measured From 100 to 200 MHz
- The multi-frequency angular power spectrum of the epoch of reionization 21 cm signal
- Characterizing Foreground for redshifted 21-cm radiation: 150 MHz GMRT observations
- Will point sources spoil 21 cm tomography?
- De-contamination of cosmological 21-cm maps
- Initial LOFAR observations of Epoch of Reionization windows: II. Diffuse polarized emission in the ELAIS-N1 field
- Constraining massive neutrinos using cosmological 21 cm observations
- Theoretical and observational constraints on the HI intensity power spectrum
- Power spectrum of HI intensity fluctuations in DDO 210
- Visibility based angular power spectrum estimation in low frequency radio interferometric observations
- GMRT observation towards detecting the Post-reionization 21-cm signal
- The impact of Galactic synchrotron emission on CMB anisotropy measurements. I. Angular power spectrum analysis of total intensity all-sky surveys
- Cosmological constraints from 21cm surveys after reionization
- Estimation of Cosmological Parameters from HI Observations of Post-reionization Epoch
- 325-MHz observations of the ELAIS-N1 field using the Giant Metrewave Radio Telescope
- Update on the BINGO 21cm intensity mapping experiment
- The Ooty Wide Field Array
- A High Speed Networked Signal Processing Platform for Multi-element Radio Telescopes
- Simulating the z = 3.35 HI 21-cm visibility signal for the Ooty Wide Field Array(OWFA)