A5035200762- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Antenna Design and Optimization
- Radio Wave Propagation Studies
- Soil Moisture and Remote Sensing
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Cryospheric studies and observations
- Millimeter-Wave Propagation and Modeling
Indian Institute of Technology Kharagpur
2022-2024
Abstract Considering radio-interferometric observations, we present a fast and efficient estimator to compute the binned angular bispectrum (ABS) from gridded visibility data. The makes use of Fast Fourier Transform techniques ABS covering all possible triangle shapes sizes. Here, formalism validate it using simulated data for Murchison Widefield Array observations at ν = 154.25 MHz. We find that our is able faithfully recover sky signal with ≈10%–15% accuracy wide variety sizes across range...
ABSTRACT We present a Wide-band tapered gridded estimator (TGE), which incorporates baseline migration and variation of the primary beam pattern for neutral hydrogen ($H\, {\small I}$) 21-cm intensity mapping (IM) with large frequency bandwidth radio-interferometric observations. Here we have analysed $394-494 \, {\rm MHz}$ (z = 1.9–2.6) uGMRT data to estimate Multifrequency Angular Power Spectrum (MAPS) Cℓ(Δν) from removed foregrounds using polynomial fitting (PF) Gaussian Process...
Abstract Drift scan observations provide the broad sky coverage and instrumental stability needed to measure Epoch of Reionization (EoR) 21-cm signal. In such observations, telescope’s pointing centre (PC) moves continuously on sky. The Tracking Tapered Gridded Estimator (TTGE) combines from different PC estimate $P(k_{\perp}, k_{\parallel})$ power spectrum, centred a tracking (TC) which remains fixed tapering further restricts response small angular region around TC, thereby mitigating...
ABSTRACT Neutral hydrogen (${\rm H\, \small {I}}$) 21-cm intensity mapping (IM) is a promising probe of the large-scale structures in Universe. However, few orders magnitude brighter foregrounds obscure IM signal. Here, we use tapered gridded estimator to estimate multifrequency angular power spectrum Cℓ(Δν) from $24.4\hbox{-} \rm {MHz}$ bandwidth upgraded Giant Metrewave Radio Telescope Band 3 data at $432.8\ {MHz}$. In remain correlated across entire Δν range, whereas signal localized...
Neutral hydrogen ($\rm{HI}$) $21$-cm intensity mapping (IM) offers an efficient technique for the large-scale structures in universe. We introduce 'Cross' Tapered Gridded Estimator (Cross TGE), which cross-correlates two cross-polarizations (RR and LL) to estimate multi-frequency angular power spectrum (MAPS) $C_{\ell}(\Delta\nu)$. expect this mitigate several effects like noise bias, calibration errors etc., affect 'Total' TGE combines polarizations. Here we apply Cross on a $24.4...
ABSTRACT The post-reionization (z ≤ 6) neutral hydrogen (H i) 21-cm intensity mapping signal holds the potential to probe large-scale structures, study expansion history, and constrain various cosmological parameters. Here, we apply Tapered Gridded Estimator (TGE) estimate P(k⊥, k∥) power spectrum of $z = 2.28\, (432.8\, {\rm MHz})$ redshifted using a $24.4\, MHz}$ sub-band drawn from uGMRT Band 3 observations European Large-Area ISO Survey-North 1 (ELAIS-N1). TGE allows us taper sky...