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arxiv: 2607.01045 · v1 · pith:3NKSC4ULnew · submitted 2026-07-01 · 🌌 astro-ph.IM

Studying Ionosphere Using SKA-Low and SKA-Mid

Abhirup Datta , Samit Kumar Pal , Sarvesh Mangla , Bhuvnesh Brawar , Sumanjit Chakraborty , Sudipta Sasmal , Anshuman Tripathi This is my paper

Pith reviewed 2026-07-02 05:19 UTC · model grok-4.3

classification 🌌 astro-ph.IM
keywords ionosphereradio interferometrySKATEC gradientscalibrationimaging fidelitypathfinder telescopesscintillation
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The pith

Observations from uGMRT, VLA, MWA and LOFAR allow forecasts of ionospheric turbulence effects on SKA-Low and SKA-Mid calibration and imaging.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper compares ionospheric disturbances across four pathfinder telescopes at different magnetic latitudes to sample complementary regimes. It uses antenna-based and field-based analyses to measure phase fluctuations, positional offsets, scintillation and TEC gradients that exceed GNSS sensitivity. These measurements quantify how turbulence affects calibration and imaging fidelity under varying geomagnetic conditions. The combined results are applied to predict the scale of similar effects during SKA-Low and SKA-Mid observations. A reader would care because such forecasts directly inform the design of mitigation strategies for low-frequency interferometry.

Core claim

By analyzing observations from the uGMRT, VLA, MWA, and LOFAR across a wide range of geographic and geomagnetic conditions, the study quantifies ionospheric phase fluctuations, positional offsets and scintillation. The measured TEC gradients provide higher spatial and temporal sensitivity than GNSS data. Combining these multi-telescope results assesses the impact of turbulence on calibration and imaging fidelity and supplies forecasts for the expected ionospheric effects on SKA-Low and SKA-Mid observations.

What carries the argument

Comparative antenna-based and field-based quantification of TEC gradients, phase fluctuations and scintillation across pathfinder arrays at different magnetic latitudes.

If this is right

  • Ionospheric turbulence will impose measurable limits on calibration accuracy and image fidelity for extended baselines at SKA frequencies.
  • SKA-Low and SKA-Mid observations will require latitude-specific mitigation strategies derived from the pathfinder measurements.
  • TEC gradient variations can be tracked at finer scales than GNSS allows, improving real-time correction models.
  • Heightened geomagnetic activity will amplify positional offsets and scintillation in proportion to the patterns seen in the pathfinder data.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same comparative method could be applied to other planned low-frequency arrays to generate site-specific ionospheric budgets before construction.
  • If pathfinder data are archived with uniform calibration metadata, they could serve as a training set for machine-learning ionospheric predictors tailored to SKA.
  • Extending the study across a full solar cycle would test whether the current forecasts remain stable under changing solar activity.

Load-bearing premise

The ionospheric regimes sampled by the pathfinder telescopes at their magnetic latitudes are representative of conditions at the SKA sites.

What would settle it

Direct SKA-Low or SKA-Mid observations that show TEC gradients, phase fluctuation statistics or scintillation indices differing substantially from the values extrapolated from the pathfinder data.

Figures

Figures reproduced from arXiv: 2607.01045 by Abhirup Datta, Anshuman Tripathi, Bhuvnesh Brawar, Samit Kumar Pal, Sarvesh Mangla, Sudipta Sasmal, Sumanjit Chakraborty.

Figure 1
Figure 1. Figure 1: Schematic overview of four calibration regimes discussed by Lonsdale (2005) for low-frequency arrays. The quantities A, S, and V are the array size on the ground, the ionospheric irregularities scale size, and the FoV at projected ionospheric altitude, respectively. For isoplanatic conditions (V<<S; Regime 1 and 2), the ionospheric phase rotation does not vary much within the FoV of each antenna. For non-i… view at source ↗
Figure 2
Figure 2. Figure 2: The differential TEC (𝛿TEC) variations are plotted as a function of time for multiple antennas located in the Central Square and along the arms of the GMRT. The 𝛿TEC values were computed along each antenna’s line of sight relative to the line of sight of the designated reference antenna (see Mangla et al., 2023) formally designated as the antenna-based method, and it is specifically designed to investigate… view at source ↗
Figure 3
Figure 3. Figure 3: The fitted coefficients (p0 to p4) along the observation. These coefficients are fitted using the second-order polynomial equation independently for each time step using each of the antenna pairs. The estimated error for each coefficient is also mentioned in the respective panel. Adapted from Mangla et al. (2023) Thus, equation 5 transforms into the following form: 𝛿TEC𝑖 − 𝛿TEC𝑗 = 𝑝0 (𝑥𝑖 − 𝑥 𝑗) + 𝑝1 (𝑦𝑖 − … view at source ↗
Figure 4
Figure 4. Figure 4: Figure shows measured TEC gradients 𝑍ˆ 𝑥 and 𝑍ˆ 𝑦 in 𝑥 and 𝑦 directions respectively (Adapted from Brawar et al., 2025). Using these TEC gradients 𝑍ˆ 𝑥 and 𝑍ˆ 𝑦 with grad2surf provides a TEC map with a mean value of zero, so to get a near true TEC measurement, we need to provide boundary conditions or an integral constant. grad2surf relies on the mathematical principle of integration (∫ 𝑓 (𝑥) 𝑑𝑥), and obta… view at source ↗
Figure 5
Figure 5. Figure 5: TEC map profile over the GMRT from (a)IRI-2016 and (b)Reconstruction from gradients during the observation period. Histograms provide the TEC fluctuation values within the area (Adapted from Brawar et al., 2025). 4 Exploring ionospheric structures using Field Based Method Unlike the antenna-based approach, wide-field radio interferometers are capable of simultaneously observing many celestial sources, resu… view at source ↗
Figure 6
Figure 6. Figure 6: Simulated Kolmogorov’s turbulence TEC screen was generated using the FFT algorithm. Adapted from Pal et al. (2025). both the inner (𝑙0) and outer (𝐿0) scales of the turbulence. The power spectrum of the spatial phase fluctuations, Φ( ®𝑘), is defined by [PITH_FULL_IMAGE:figures/full_fig_p016_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Left: Ionospheric-induced phase variations between the beginning and end of a band of 1, 5, and 10 SKA-Low AA4 sub bands (1SB ≃ 0.006 MHz). Assumed 𝛿TEC is 0.4, 0.7, 1.0 TECU. These values were considered for baseline lengths of a few tens of kilometers. SKA-Low frequency bandwidth is 50-350 MHz. Right: Dynamic range (𝐷𝑅) as a function of frequency for sub bands 1, 5, and 10 (1SB ≃ 0.006 MHz). The phase er… view at source ↗
Figure 8
Figure 8. Figure 8: Left: Ionospheric-induced phase variations between the beginning and end of a band of 1, 5, and 10 SKA-Mid AA4 sub bands (1SB ≃ 0.01375 MHz). Assumed 𝛿TEC is 0.8, 1.4, 2.0 TECU. SKA-Mid frequency bandwidths are 0.350-1.05 GHz (Band 1; violet), 0.95-1.76 GHz (Band 2; red), and 4.6-15.3 GHz (Band 5; yellow). Right: Dynamic range (𝐷𝑅) as a function of frequency for sub bands 1, 5, and 10 (1SB ≃ 0.01375 MHz). … view at source ↗
read the original abstract

The Earth's ionosphere introduces systematic effects that limit the performance of radio interferometers operating at low frequencies ($\lesssim 1$\,GHz). These ionospheric effects intensify during periods of heightened geomagnetic activity or for observations with extended baseline configurations. As each Pathfinder telescope operates at a different magnetic latitude, they experience distinct ionospheric regimes, offering complementary insights into ionospheric behaviour. In this work, we present a comparative study of ionospheric disturbances using observations from the uGMRT, VLA, MWA, and LOFAR, spanning a wide range of geographic and geomagnetic conditions. We present both antenna-based and field-based analyses to quantify phase fluctuations, positional offsets, and scintillation effects across these arrays. The measured total electron content (TEC) gradients reveal variations in spatial and temporal ionospheric structures with sensitivities that exceed those achievable with Global Navigation Satellite System (GNSS) measurements. By combining multi-telescope results, we assess the impact of ionospheric turbulence on calibration and imaging fidelity, and use these findings to forecast the expected ionospheric effects on observations with SKA-Low and SKA-Mid.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 0 minor

Summary. The manuscript presents a comparative study of ionospheric disturbances observed with uGMRT, VLA, MWA, and LOFAR across a range of geographic and geomagnetic conditions. It reports both antenna-based and field-based analyses that quantify phase fluctuations, positional offsets, and scintillation, compares measured TEC gradients to GNSS sensitivities, evaluates impacts on calibration and imaging fidelity, and uses the combined results to forecast ionospheric effects expected for SKA-Low and SKA-Mid.

Significance. If the representativeness of the pathfinder regimes for SKA sites can be established, the multi-telescope comparison would supply useful empirical constraints on ionospheric turbulence statistics at low frequencies and aid SKA observing strategies. The emphasis on TEC gradients exceeding GNSS sensitivity is a concrete strength of the approach.

major comments (1)
  1. [Abstract] Abstract: the forecasting step for SKA-Low and SKA-Mid rests on the assumption that ionospheric turbulence statistics measured at the pathfinder sites can be mapped or extrapolated to the SKA sites. No quantitative comparison of geomagnetic latitudes, no adjustment via an ionospheric model (e.g., IRI or NeQuick) for latitude or solar-cycle differences, and no cross-validation against independent SKA-site data or simulations are described. This assumption is load-bearing for the central claim.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for highlighting this important point regarding the extrapolation to SKA sites. We address the concern directly below and will revise the manuscript to provide a clearer justification.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the forecasting step for SKA-Low and SKA-Mid rests on the assumption that ionospheric turbulence statistics measured at the pathfinder sites can be mapped or extrapolated to the SKA sites. No quantitative comparison of geomagnetic latitudes, no adjustment via an ionospheric model (e.g., IRI or NeQuick) for latitude or solar-cycle differences, and no cross-validation against independent SKA-site data or simulations are described. This assumption is load-bearing for the central claim.

    Authors: We agree that the manuscript does not contain an explicit quantitative comparison of geomagnetic latitudes or model-based adjustments, and that this weakens the forecasting claim. The pathfinders were chosen to sample a range of latitudes and conditions (MWA at a latitude comparable to SKA-Low; LOFAR, VLA and uGMRT providing mid- and higher-latitude coverage), but we did not tabulate or scale the statistics accordingly. In revision we will add a concise comparison of geomagnetic latitudes for all sites versus the SKA locations, together with a short discussion of latitude-dependent ionospheric behaviour drawn from the literature. We will also note the solar-cycle phase of the observations. This will make the extrapolation step more transparent. We do not have access to independent SKA-site data or new simulations, so cross-validation of that form is not feasible at present. revision: yes

Circularity Check

0 steps flagged

No circularity; empirical comparison across independent instruments

full rationale

The paper describes a data-driven comparative analysis of ionospheric effects measured directly from uGMRT, VLA, MWA, and LOFAR observations at different latitudes. These measurements are used to assess impacts and forecast SKA effects via empirical combination. No equations, fitted parameters renamed as predictions, self-citations as load-bearing premises, or self-definitional steps appear in the provided text. The forecasting step relies on an external representativeness assumption rather than reducing to the input data by construction. This is a standard observational study with independent external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review; no free parameters, axioms, or invented entities are specified in the available text.

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discussion (0)

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Reference graph

Works this paper leans on

181 extracted references · 136 canonical work pages · 38 internal anchors

  1. [1]

    The Cosmic 21-cm Revolution , publisher =

    Chapman, Emma and Jeli\'c, Vibor , title =. The Cosmic 21-cm Revolution , publisher =. 2019 , series =. doi:10.1088/2514-3433/ab4a73ch6 , isbn =

    work page doi:10.1088/2514-3433/ab4a73ch6 2019

  2. [2]

    , volume =

    Mesarcik, Michael and Boonstra, Albert-Jan and Ranguelova, Elena and van Nieuwpoort, Rob V , title =. , volume =. 2022 , month =. doi:10.1093/mnras/stac2503 , url =

    work page doi:10.1093/mnras/stac2503 2022

  3. [3]

    , keywords =

    RFI detection with spiking neural networks. , keywords =. doi:10.1017/pasa.2024.27 , archivePrefix =. 2311.14303 , primaryClass =

    work page doi:10.1017/pasa.2024.27 2024

  4. [4]

    2010 , month = mar, journal =

    Post-correlation radio frequency interference classification methods. MNRAS , keywords =. doi:10.1111/j.1365-2966.2010.16471.x , archivePrefix =. 1002.1957 , primaryClass =

    work page doi:10.1111/j.1365-2966.2010.16471.x 2010

  5. [5]

    Understanding Instrumental Stokes Leakage in Murchison Widefield Array Polarimetry

    Understanding instrumental Stokes leakage in Murchison Widefield Array polarimetry. Radio Science , keywords =. doi:10.1002/2014RS005517 , archivePrefix =. 1412.4466 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1002/2014rs005517

  6. [6]

    The Effects of Polarized Foregrounds on 21cm Epoch of Reionization Power Spectrum Measurements

    The Effects of Polarized Foregrounds on 21 cm Epoch of Reionization Power Spectrum Measurements. , keywords =. doi:10.1088/0004-637X/769/2/154 , archivePrefix =. 1302.0876 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/769/2/154

  7. [7]

    , keywords =

    On the contamination of the global 21-cm signal from polarized foregrounds. , keywords =. doi:10.1093/mnras/stz2425 , archivePrefix =. 1908.05303 , primaryClass =

    work page doi:10.1093/mnras/stz2425 1908

  8. [8]

    Simulations of Galactic polarized synchrotron emission for Epoch of Reionization observations

    Simulations of Galactic polarized synchrotron emission for Epoch of Reionization observations. , keywords =. doi:10.1093/mnras/sty1457 , archivePrefix =. 1802.03060 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/sty1457

  9. [9]

    Constraining Polarized Foregrounds for EoR Experiments. II. Polarization Leakage Simulations in the Avoidance Scheme. , keywords =. doi:10.3847/1538-4357/aa8b73 , archivePrefix =. 1707.04109 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/aa8b73

  10. [10]

    Polarization leakage in epoch of reionization windows: III. Wide-field effects of narrow-field arrays

    Polarization leakage in epoch of reionization windows - III. Wide-field effects of narrow-field arrays. , keywords =. doi:10.1093/mnras/sty258 , archivePrefix =. 1706.00875 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/sty258

  11. [11]

    Polarization leakage in epoch of reionization windows: II. Primary beam model and direction dependent calibration

    Polarization leakage in epoch of reionization windows - II. Primary beam model and direction-dependent calibration. , keywords =. doi:10.1093/mnras/stw1863 , archivePrefix =. 1604.04534 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stw1863

  12. [12]

    Polarization leakage in Epoch of Reionization windows: I. LOFAR observations of the 3C196 field

    Polarization leakage in epoch of reionization windows - I. Low Frequency Array observations of the 3C196 field. , keywords =. doi:10.1093/mnras/stv1107 , archivePrefix =. 1503.01644 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stv1107

  13. [13]

    A 189 MHz, 2400 square degree polarization survey with the Murchison Widefield Array 32-element prototype

    A 189 MHz, 2400 deg ^ 2 Polarization Survey with the Murchison Widefield Array 32-element Prototype. , keywords =. doi:10.1088/0004-637X/771/2/105 , archivePrefix =. 1305.6047 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/771/2/105

  14. [14]

    , keywords =

    LOFAR Deep Fields: Probing faint Galactic polarised emission in ELAIS-N1. , keywords =. doi:10.1051/0004-6361/202245124 , archivePrefix =. 2303.13152 , primaryClass =

    work page doi:10.1051/0004-6361/202245124

  15. [15]

    Faraday tomography of LoTSS-DR2 data. III. Revealing the Local Bubble and the complex of local interstellar clouds in the high-latitude inner Galaxy. , keywords =. doi:10.1051/0004-6361/202450082 , archivePrefix =. 2406.14679 , primaryClass =

    work page doi:10.1051/0004-6361/202450082

  16. [16]

    Faraday tomography of LoTSS-DR2 data. I. Faraday moments in the high-latitude outer Galaxy and revealing Loop III in polarisation. , keywords =. doi:10.1051/0004-6361/202142244 , archivePrefix =. 2203.01351 , primaryClass =

    work page doi:10.1051/0004-6361/202142244

  17. [17]

    Faraday Rotation Measure Synthesis

    Faraday rotation measure synthesis. , keywords =. doi:10.1051/0004-6361:20052990 , archivePrefix =. astro-ph/0507349 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361:20052990

  18. [18]

    Low frequency observations of linearly polarized structures in the interstellar medium near the south Galactic pole

    Low-frequency Observations of Linearly Polarized Structures in the Interstellar Medium near the South Galactic Pole. , keywords =. doi:10.3847/0004-637X/830/1/38 , archivePrefix =. 1607.05779 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/0004-637x/830/1/38

  19. [19]

    , keywords =

    The GMRT EoR experiment: limits on polarized sky brightness at 150 MHz. , keywords =. doi:10.1111/j.1365-2966.2009.14980.x , archivePrefix =. 0807.1056 , primaryClass =

    work page doi:10.1111/j.1365-2966.2009.14980.x 2009

  20. [20]

    Linear polarization structures in LOFAR observations of the interstellar medium in the 3C196 field

    Linear polarization structures in LOFAR observations of the interstellar medium in the 3C 196 field. , keywords =. doi:10.1051/0004-6361/201526638 , archivePrefix =. 1508.06650 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201526638

  21. [21]

    Initial LOFAR observations of epoch of reionization windows. II. Diffuse polarized emission in the ELAIS-N1 field. , keywords =. doi:10.1051/0004-6361/201423998 , archivePrefix =. 1407.2093 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201423998 2093

  22. [22]

    Foregrounds for observations of the cosmological 21 cm line. II. Westerbork observations of the fields around 3C 196 and the North Celestial Pole. , keywords =. doi:10.1051/0004-6361/200913420 , archivePrefix =. 1002.4177 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/200913420

  23. [23]

    Foregrounds for observations of the cosmological 21 cm line. I. First Westerbork measurements of Galactic emission at 150 MHz in a low latitude field. , keywords =. doi:10.1051/0004-6361/200911627 , archivePrefix =. 0904.0404 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/200911627

  24. [24]

    and Lightman, Alan P

    Rybicki, George B. and Lightman, Alan P. , title =. 1979 , address =

    1979

  25. [25]

    , title =

    Pacholczyk, Andrzej G. , title =. 1970 , address =

    1970

  26. [26]

    Burn, B. J. , title =. , year =

  27. [27]

    2010 , month = mar, journal =

    Realistic simulations of the Galactic polarized foreground: consequences for 21-cm reionization detection experiments. , keywords =. doi:10.1111/j.1365-2966.2010.17407.x , archivePrefix =. 1007.4135 , primaryClass =

    work page doi:10.1111/j.1365-2966.2010.17407.x 2010

  28. [28]

    2015 , publisher=

    Advancing Astrophysics with the Square Kilometre Array (AASKA14) , author=. 2015 , publisher=

    2015

  29. [29]

    and Morales, Miguel F

    Wilensky, Michael J. and Morales, Miguel F. and Hazelton, Bryna J. and Star, Pyxie L. and Barry, Nichole and Byrne, Ruby and Jordan, C. H. and Jacobs, Daniel C. and Pober, Jonathan C. and Trott, C. M. , year=. Evidence of Ultrafaint Radio Frequency Interference in Deep 21 cm Epoch of Reionization Power Spectra with the Murchison Wide-field Array , volume=...

    work page doi:10.3847/1538-4357/acffbd

  30. [30]

    Satellite

    Wang, Yu and Zhang, Hai-Yan and Hu, Hao and Huang, Shi-Jie and Zhu, Wei-Wei and Zhi, Guo-Ping and Zhang, Tao and Fan, Zhan-Chun and Yang, Li , year =. Satellite. doi:10.1088/1674-4527/21/1/18 , journal =

    work page doi:10.1088/1674-4527/21/1/18

  31. [31]

    Aggregate Interference Analysis of a LEO Satellite Constellation into the Radio Astronomy Observatory , year=

    Yilmaz, Mustafa Harun , booktitle=. Aggregate Interference Analysis of a LEO Satellite Constellation into the Radio Astronomy Observatory , year=

  32. [32]

    Proceedings of the 4th URSI Atlantic Radio Science Conference (AT-RASC) , year =

    Giorgio Siringo and Sean Dougherty , title =. Proceedings of the 4th URSI Atlantic Radio Science Conference (AT-RASC) , year =

  33. [33]

    Radio frequency interference from radio navigation satellite systems: simulations and comparison to

    Engelbrecht, Brandon N and Santos, Mario G and Fonseca, José and Li, Yichao and Wang, Jingying and Irfan, Melis O and Harper, Stuart E and Grainge, Keith and Bull, Philip and Carucci, Isabella P and Cunnington, Steven and Pourtsidou, Alkistis and Spinelli, Marta and Wolz, Laura , year =. Radio frequency interference from radio navigation satellite systems...

    work page doi:10.1093/mnras/stae2649

  34. [34]

    and Zarka, P

    Zhang, X. and Zarka, P. and Viou, C. and Loh, A. and Bassa, C. G. and Duchene, Q. and Tasse, C. and Grießmeier, J.-M. and Turner, J. D. and Ulyanov, O. and Koopmans, L. V. E. and Mertens, F. and Zakharenko, V. and Briand, C. and Cecconi, B. and Vermeulen, R. and Konovalenko, O. and Girard, J. N. and Corbel, S. , year=. Broadband polarized radio emission d...

    work page doi:10.1051/0004-6361/202554152

  35. [35]

    and De Pree, Christopher G

    Nhan, Bang D. and De Pree, Christopher G. and Iverson, Matt and Gregory, Brenne and Dueri, Daniel and Beasley, Anthony and Schepis, Brian , year =. Toward. doi:10.3847/2041-8213/ad6b24 , journal =

    work page doi:10.3847/2041-8213/ad6b24 2041

  36. [36]

    Astronomy & Astrophysics , keywords =

    Unintended electromagnetic radiation from Starlink satellites detected with LOFAR between 110 and 188 MHz. Astronomy & Astrophysics , keywords =. doi:10.1051/0004-6361/202346374 , archivePrefix =. 2307.02316 , primaryClass =

    work page doi:10.1051/0004-6361/202346374

  37. [37]

    , keywords =

    Comparing foreground removal techniques for recovery of the LOFAR-EoR 21 cm power spectrum. , keywords =. doi:10.1093/mnras/staa3446 , archivePrefix =. 2011.01284 , primaryClass =

    work page doi:10.1093/mnras/staa3446 2011

  38. [38]

    A.Tripathi,A.Datta,A.Mazumder,andS.Majumdar.J.Cosmol.Astropart.Phys.,2025(10):035, Oct

    Comparing sampling techniques to chart parameter space of 21 cm global signal with Artificial Neural Networks. , keywords =. doi:10.1088/1475-7516/2024/10/041 , archivePrefix =. 2406.15832 , primaryClass =

    work page doi:10.1088/1475-7516/2024/10/041 2024

  39. [39]

    , volume =

    Tripathi, Anshuman and Datta, Abhirup and Choudhury, Madhurima and Majumdar, Suman , title = ". , volume =. 2024 , month =. doi:10.1093/mnras/stae078 , url =

    work page doi:10.1093/mnras/stae078 2024

  40. [40]

    , keywords =

    Extracting the 21 cm Global signal using artificial neural networks. , keywords =. doi:10.1093/mnras/stz3107 , archivePrefix =. 1911.02580 , primaryClass =

    work page doi:10.1093/mnras/stz3107 1911

  41. [41]

    , keywords =

    Using artificial neural networks to extract the 21-cm global signal from the EDGES data. , keywords =. doi:10.1093/mnras/stab180 , archivePrefix =. 2012.00028 , primaryClass =

    work page doi:10.1093/mnras/stab180 2012

  42. [42]

    The Tiered Radio Extragalactic Continuum Simulation (T-RECS)

    The Tiered Radio Extragalactic Continuum Simulation (T-RECS). , keywords =. doi:10.1093/mnras/sty2603 , archivePrefix =. 1805.05222 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/sty2603

  43. [43]

    , keywords =

    Observing the reionization: effect of calibration and position errors on realistic observation conditions. , keywords =. doi:10.1093/mnras/stac1994 , archivePrefix =. 2207.06169 , primaryClass =

    work page doi:10.1093/mnras/stac1994

  44. [44]

    , keywords =

    Extracting the 21-cm power spectrum and the reionization parameters from mock data sets using artificial neural networks. , keywords =. doi:10.1093/mnras/stac736 , archivePrefix =. 2112.13866 , primaryClass =

    work page doi:10.1093/mnras/stac736

  45. [45]

    arXiv e-prints , keywords =

    Impact of Calibration and Position Errors on Astrophysical Parameters of the 21cm Signal. arXiv e-prints , keywords =. doi:10.48550/arXiv.2502.20962 , archivePrefix =. 2502.20962 , primaryClass =

    work page doi:10.48550/arxiv.2502.20962

  46. [46]

    image recovery , author=

    Deep learning approach for identification of Hii regions during reionization in 21-cm observations--III. image recovery , author=. , pages=. 2025 , publisher=

    2025

  47. [47]

    Foreground contamination , author=

    Deep learning approach for identification of h ii regions during reionization in 21-cm observations--II. Foreground contamination , author=. , volume=. 2024 , publisher=

    2024

  48. [48]

    , volume=

    Deep learning approach for identification of H II regions during reionization in 21-cm observations , author=. , volume=. 2021 , publisher=

    2021

  49. [49]

    arXiv preprint arXiv:2508.13265 , year=

    Field-level Reconstruction from Foreground-Contaminated 21-cm Maps , author=. arXiv preprint arXiv:2508.13265 , year=

    work page arXiv

  50. [50]

    , volume=

    Recovering the wedge modes lost to 21-cm foregrounds , author=. , volume=. 2021 , publisher=

    2021

  51. [51]

    Physical Review D , volume=

    21-cm foreground removal using AI and the frequency-difference technique , author=. Physical Review D , volume=. 2024 , publisher=

    2024

  52. [52]

    Journal of Cosmology and Astroparticle Physics , volume=

    deep21: a deep learning method for 21 cm foreground removal , author=. Journal of Cosmology and Astroparticle Physics , volume=. 2021 , publisher=

    2021

  53. [53]

    , volume=

    Separating the EoR signal with a convolutional denoising autoencoder: a deep-learning-based method , author=. , volume=. 2019 , publisher=

    2019

  54. [54]

    The Astrophysical Journal , volume=

    Extracting the Epoch of Reionization Signal with 3D U-Net Neural Networks Using a Data-driven Systematic Effect Model , author=. The Astrophysical Journal , volume=. 2025 , publisher=

    2025

  55. [55]

    , volume=

    Retrieving the 21-cm signal from the Epoch of Reionization with learnt Gaussian process kernels , author=. , volume=. 2024 , publisher=

    2024

  56. [56]

    , volume=

    21-cm signal from the Epoch of Reionization: a machine learning upgrade to foreground removal with Gaussian process regression , author=. , volume=. 2024 , publisher=

    2024

  57. [57]

    , volume=

    Optimal identification of H II regions during reionization in 21-cm observations , author=. , volume=. 2018 , publisher=

    2018

  58. [58]

    arXiv preprint arXiv:2505.06350 , year=

    Mapping neutral islands during end stages of reionization with photometric intergalactic medium tomography , author=. arXiv preprint arXiv:2505.06350 , year=

    work page arXiv

  59. [59]

    1990 , publisher=

    Ionospheric radio , author=. 1990 , publisher=

    1990

  60. [60]

    and Juan, J

    Hernández-Pajares, M. and Juan, J. M. and Sanz, J. , title =. Journal of Geophysical Research: Space Physics , volume =. doi:10.1029/2005JA011474 , abstract =

    work page doi:10.1029/2005ja011474

  61. [61]

    Synthesis Imaging in Radio Astronomy II , year = 1999, editor =

    Fundamentals of Radio Interferometry. Synthesis Imaging in Radio Astronomy II , year = 1999, editor =

    1999

  62. [62]

    Radio Science , keywords =

    Estimate of higher order ionospheric errors in GNSS positioning. Radio Science , keywords =. doi:10.1029/2007RS003817 , adsurl =

    work page doi:10.1029/2007rs003817

  63. [63]

    A. S. Cohen and H. J. A. Röttgering , title =. The Astronomical Journal , abstract =. doi:10.1088/0004-6256/138/2/439 , url =

    work page doi:10.1088/0004-6256/138/2/439

  64. [64]

    A New Technique for Spectral Analysis of Ionospheric TEC Fluctuations Observed with the Very Large Array VHF System: From QP Echoes to MSTIDs

    A new technique for spectral analysis of ionospheric TEC fluctuations observed with the Very Large Array VHF system: From QP echoes to MSTIDs. Radio Science , keywords =. doi:10.1029/2011RS004787 , archivePrefix =. 1201.3874 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1029/2011rs004787

  65. [65]

    Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array

    Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array. Radio Science , keywords =. doi:10.1002/2015RS005711 , archivePrefix =. 1506.01798 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1002/2015rs005711

  66. [66]

    Current Science , year = 1991, month = jan, volume =

    The Giant Metre-Wave Radio Telescope. Current Science , year = 1991, month = jan, volume =

    1991

  67. [67]

    Current Science , year = 2017, month = aug, volume =

    The upgraded GMRT: opening new windows on the radio Universe. Current Science , year = 2017, month = aug, volume =. doi:10.18520/cs/v113/i04/707-714 , adsurl =

    work page doi:10.18520/cs/v113/i04/707-714 2017

  68. [68]

    Nature , year = 1946, month = may, volume =

    Two Anomalies in the Ionosphere. Nature , year = 1946, month = may, volume =. doi:10.1038/157691a0 , adsurl =

    work page doi:10.1038/157691a0 1946

  69. [69]

    Radio Science , keywords =

    Ionospheric Irregularities Observed During the GLEAM Survey. Radio Science , keywords =. doi:10.1029/2020RS007106 , adsurl =

    work page doi:10.1029/2020rs007106

  70. [70]

    Radio Science , keywords =

    A study of precursors to equatorial spread F using the Giant Meterwave Radio Telescope. Radio Science , keywords =. doi:10.1029/2007RS003667 , adsurl =

    work page doi:10.1029/2007rs003667

  71. [71]

    and van der Tol, S

    Mevius, M. and van der Tol, S. and Pandey, V. N. and Vedantham, H. K. and Brentjens, M. A. and de Bruyn, A. G. and Abdalla, F. B. and Asad, K. M. B. and Bregman, J. D. and Brouw, W. N. and Bus, S. and Chapman, E. and Ciardi, B. and Fernandez, E. R. and Ghosh, A. and Harker, G. and Iliev, I. T. and Jelić, V. and Kazemi, S. and Koopmans, L. V. E. and Noorda...

    work page doi:10.1002/2016rs006028

  72. [72]

    10.1051/0004-6361/201833012

    The effect of the ionosphere on ultra-low-frequency radio-interferometric observations , DOI= "10.1051/0004-6361/201833012", url= "https://doi.org/10.1051/0004-6361/201833012", journal =

    work page doi:10.1051/0004-6361/201833012

  73. [73]

    Wayth, R. B. and Lenc, E. and Bell, M. E. and Callingham, J. R. and Dwarakanath, K. S. and Franzen, T. M. O. and For, B.-Q. and Gaensler, B. and Hancock, P. and Hindson, L. and et al. , year=. GLEAM: The GaLactic and Extragalactic All-Sky MWA Survey , volume=. doi:10.1017/pasa.2015.26 , journal=

    work page doi:10.1017/pasa.2015.26 2015

  74. [74]

    Climatology of Mid-latitude Ionospheric Disturbances from the Very Large Array Low-frequency Sky Survey

    Climatology of midlatitude ionospheric disturbances from the Very Large Array Low-frequency Sky Survey. Radio Science , keywords =. doi:10.1029/2012RS005025 , archivePrefix =. 1209.1030 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1029/2012rs005025

  75. [75]

    Radio Science , keywords =

    Bounding higher-order ionosphere errors for the dual-frequency GPS user. Radio Science , keywords =. doi:10.1029/2007RS003772 , adsurl =

    work page doi:10.1029/2007rs003772

  76. [76]

    Synthesis Imaging in Radio Astronomy II , year = 1999, editor =

    Self-Calibration. Synthesis Imaging in Radio Astronomy II , year = 1999, editor =

    1999

  77. [77]

    Advances in Space Research , keywords =

    Performance of NavIC for studying the ionosphere at an EIA region in India. Advances in Space Research , keywords =. doi:10.1016/j.asr.2019.12.019 , archivePrefix =. 2001.02964 , primaryClass =

    work page doi:10.1016/j.asr.2019.12.019 2019

  78. [78]

    LOFAR facet calibration

    LOFAR Facet Calibration. ApJS , keywords =. doi:10.3847/0067-0049/223/1/2 , archivePrefix =. 1601.05422 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/0067-0049/223/1/2

  79. [79]

    G and Kelley, M

    Fejer, B. G and Kelley, M. C. , title =. Reviews of Geophysics , volume =. doi:https://doi.org/10.1029/RG018i002p00401 , url =. https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/RG018i002p00401 , abstract =

    work page doi:10.1029/rg018i002p00401

  80. [80]

    and La Hoz, César , title =

    Woodman, Ronald F. and La Hoz, César , title =. Journal of Geophysical Research (1896-1977) , volume =. doi:https://doi.org/10.1029/JA081i031p05447 , abstract =

    work page doi:10.1029/ja081i031p05447 1977

Showing first 80 references.