Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at $\mathbf{z}\approx 9.1$ from LOFAR

Abstract

A new upper limit on the 21-cm signal power spectrum at a redshift of $z\approx 9.1$ is presented, based on 141 hours of data obtained with the Low-Frequency Array (LOFAR). The analysis includes significant improvements in spectrally-smooth gain-calibration, Gaussian Process Regression (GPR) foreground mitigation and optimally-weighted power spectrum inference. Previously seen `excess power' due to spectral structure in the gain solutions has markedly reduced but some excess power still remains with a spectral correlation distinct from thermal noise. This excess has a spectral coherence scale of $0.25-0.45$\,MHz and is partially correlated between nights, especially in the foreground wedge region. The correlation is stronger between nights covering similar local sidereal times. A best 2-$\sigma$ upper limit of ${\Delta }_{21}^2<(73{)}^2\mathrm{m}{\mathrm{K}}^2$ at $k=0.075\mathrm{h}\mathrm{cMp}{\mathrm{c}}^{-1}$ is found, an improvement by a factor $\approx 8$ in power compared to the previously reported upper limit. The remaining excess power could be due to residual foreground emission from sources or diffuse emission far away from the phase centre, polarization leakage, chromatic calibration errors, ionosphere, or low-level radio-frequency interference. We discuss future improvements to the signal processing chain that can further reduce or even eliminate these causes of excess power.

27 pages, 14 figues, accepted in MNRAS (updated with reference to accompanying paper)

References in corpus (21)

• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• The Epoch of Reionization Window: I. Mathematical Formalism
• The Very Large Array Low-frequency Sky Survey Redux (VLSSr)
• Foreground simulations for the LOFAR - Epoch of Reionization Experiment
• The Epoch of Reionization Window: II. Statistical Methods for Foreground Wedge Reduction
• Signature of Excess Radio Background in the 21-cm Global Signal and Power Spectrum
• First Season MWA EoR Power Spectrum Results at Redshift 7
• A simplified, lossless re-analysis of PAPER-64
• Improving the Epoch of Reionization Power Spectrum Results from Murchison Widefield Array Season 1 Observations
• The Scale of the Problem : Recovering Images of Reionization with GMCA
• 21 cm signal from cosmic dawn: Imprints of spin temperature fluctuations and peculiar velocities
• Constraining the intergalactic medium at $z\approx$ 9.1 using LOFAR Epoch of Reionization observations
• First Season MWA Phase II EoR Power Spectrum Results at Redshift 7
• The LOFAR radio environment
• Distributed Radio Interferometric Calibration
• Mitigating Internal Instrument Coupling II: A Method Demonstration with the Hydrogen Epoch of Reionization Array
• Mitigating Internal Instrument Coupling for 21 cm Cosmology I: Temporal and Spectral Modeling in Simulations
• SZ and CMB reconstruction using Generalized Morphological Component Analysis
• Temporal Variability in Hot Jupiter Atmospheres
• The impact of interference excision on 21-cm Epoch of Reionization power spectrum analyses
• Precision requirements for interferometric gridding in 21-cm power spectrum analysis

Cited by in corpus (226)

• First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
• HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
• The Impact of the First Galaxies on Cosmic Dawn and Reionization
• Astraeus I: The interplay between galaxy formation and reionization
• The search for radio emission from the exoplanetary systems 55 Cancri, $\upsilon$ Andromedae, and $\tau$ Boötis using LOFAR beam-formed observations
• Constraining the intergalactic medium at $z\approx$ 9.1 using LOFAR Epoch of Reionization observations
• Tight Constraints on the Excess Radio Background at $z=9.1$ from LOFAR
• High-redshift radio galaxies: a potential new source of 21-cm fluctuations
• Interpreting LOFAR 21-cm signal upper limits at z~9.1 in the context of high-z galaxy and reionisation observations
• The subtlety of Ly-a photons: changing the expected range of the 21-cm signal
• Emulating the Global 21-cm Signal from Cosmic Dawn and Reionization
• 21cm foregrounds and polarization leakage: a user's guide on cleaning and mitigation strategies
• Simulation-Based Inference of Reionization Parameters From 3D Tomographic 21 cm Lightcone Images
• An Intensity Mapping Detection of Aggregate CO Line Emission at 3 mm
• A new MWA limit on the 21 cm Power Spectrum at Redshifts $\sim$ 13 $-$ 17
• Exploring reionisation and high-z galaxy observables with recent multi-redshift MWA upper limits on the 21-cm signal
• Constraining the state of the intergalactic medium during the Epoch of Reionization using MWA 21-cm signal observations
• First upper limits on the 21 cm signal power spectrum from cosmic dawn from one night of observations with NenuFAR
• Comparing Foreground Removal Techniques for Recovery of the LOFAR-EoR 21cm Power Spectrum
• Redundant-Baseline Calibration of the Hydrogen Epoch of Reionization Array
• Gaussian Process Foreground Subtraction and Power Spectrum Estimation for 21 cm Cosmology
• Measuring the topology of reionization with Betti numbers
• A 21-cm power spectrum at 48 MHz, using the Owens Valley Long Wavelength Array
• A halo model approach for the 21-cm power spectrum at cosmic dawn
• DAYENU: A Simple Filter of Smooth Foregrounds for Intensity Mapping Power Spectra
• Impact of the Primordial Stellar Initial Mass Function on the 21-cm Signal
• Machine learning astrophysics from 21 cm lightcones: impact of network architectures and signal contamination
• The AARTFAAC Cosmic Explorer: observations of the 21-cm power spectrum in the EDGES absorption trough
• Prospects for precision cosmology with the 21 cm signal from the dark ages
• Implicit Likelihood Inference of Reionization Parameters from the 21 cm Power Spectrum
• Redshifted 21-cm Bispectrum I: Impact of the Redshift Space Distortions on the Signal from the Epoch of Reionization
• Gaussian Process Regression for foreground removal in HI intensity mapping experiments
• Exploring the likelihood of the 21-cm power spectrum with simulation-based inference
• Redshift-space distortions in simulations of the 21-cm signal from the cosmic dawn
• A Unified Calibration Framework for 21 cm Cosmology
• Deep learning approach for identification of HII regions during reionization in 21-cm observations
• Elevated UV luminosity density at Cosmic Dawn explained by non-evolving, weakly mass-dependent star formation efficiency
• 21cmEMU: an emulator of 21cmFAST summary observables
• Redshifted 21-cm bispectrum II: Impact of the spin temperature fluctuations and redshift space distortions on the signal from the Cosmic Dawn
• Patterns of primary beam non-redundancy in close-packed 21 cm array observations
• Improving constraints on the reionization parameters using 21-cm bispectrum
• Prospects of constraining reionization model parameters using Minkowski tensors and Betti numbers
• The Second Radio Synchrotron Background Workshop: Conference Summary and Report
• Constraining the X-ray heating and reionization using 21-cm power spectra with Marginal Neural Ratio Estimation
• Array Element Coupling in Radio Interferometry I: A Semi-Analytic Approach
• A numerical study of 21-cm signal suppression and noise increase in direction-dependent calibration of LOFAR data
• Quantifying Excess Power from Radio Frequency Interference in Epoch of Reionization Measurements
• Demonstrating the Tapered Gridded Estimator (TGE) for the Cosmological HI 21-cm Power Spectrum using $150\mathrm{MHz}$ GMRT observations
• Foreground modelling via Gaussian process regression: an application to HERA data
• New EoR Power Spectrum Limits From MWA Phase II Using the Delay Spectrum Method and Novel Systematic Rejection
• Predictions for measuring the 21-cm multi-frequency angular power spectrum using SKA-Low
• COMAP Early Science: IV. Power Spectrum Methodology and Results
• Deeper multi-redshift upper limits on the Epoch of Reionization 21-cm signal power spectrum from LOFAR between z=8.3 and z=10.1
• Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline
• Inferring the properties of the sources of reionization using the morphological spectra of the ionized regions
• Structure Formation and the Global 21-cm Signal in the Presence of Coulomb-like Dark Matter-Baryon Interactions
• The impact of inhomogeneous subgrid clumping on cosmic reionization II: modelling stochasticity
• Improved treatments of the ionizing photon mean free path in semi-numerical simulations of reionization
• Spectral index of synchrotron emission: insights from the diffuse and magnetised interstellar medium
• Assessing the impact of two independent direction-dependent calibration algorithms on the LOFAR 21-cm signal power spectrum
• Cosmic Reionization May Still Have Started Early and Ended Late: Confronting Early Onset with CMB Anisotropy and 21 cm Global Signals
• Studying Cosmic Dawn using redshifted HI 21-cm signal: A brief review
• Modelling and peeling extended sources with shapelets: a Fornax A case study
• The Epoch of Reionization 21-cm Bispectrum: The impact of light-cone effects and detectability
• Shot noise and scatter in the star formation efficiency as a source of 21-cm fluctuations
• Extracting the 21 cm EoR signal using MWA drift scan data
• The impact of non-Gaussianity on the Epoch of Reionization parameter forecast using 21-cm power spectrum measurements
• Statistical recovery of 21cm visibilities and their power spectra with Gaussian constrained realisations and Gibbs sampling
• 21cmfish: Fisher-matrix framework for fast parameter forecasts from the cosmic 21-cm signal
• Deep learning approach for identification of HII regions during reionization in 21-cm observations -- II. foreground contamination
• BEoRN: A fast and flexible framework to simulate the epoch of reionisation and cosmic dawn
• The Impact of Beam Variations on Power Spectrum Estimation for 21-cm Cosmology I: Simulations of Foreground Contamination for HERA
• An Effective Bias Expansion for 21 cm Cosmology in Redshift Space
• Statistical analysis of the causes of excess variance in the 21 cm signal power spectra obtained with the Low-Frequency Array
• Extracting the 21-cm Power Spectrum and the reionization parameters from mock datasets using Artificial Neural Networks
• The bispectrum and 21cm foregrounds during the Epoch of Reionization
• Exploiting synergies between JWST and cosmic 21-cm observations to uncover star formation in the early Universe
• Signatures of Cosmic Ray Heating in 21-cm Observables
• The large-scale 21-cm power spectrum from reionization
• How informative are summaries of the cosmic 21-cm signal?
• Evidence of Ultra-faint Radio Frequency Interference in Deep 21~cm Epoch of Reionization Power Spectra with the Murchison Widefield Array
• The role of Pop III stars and early black holes in the 21cm signal from Cosmic Dawn
• Investigating X-ray sources during the epoch of reionization with the 21 cm signal
• The detectability of strong 21 centimetre forest absorbers from the diffuse intergalactic medium in late reionisation models
• Observing the Reionization : Effect of Calibration and Position Errors on Realistic Observation Conditions
• Impact of dark matter models on the EoR 21-cm signal bispectrum
• 21cmFirstCLASS I. Cosmological tool for $\Lambda$CDM and beyond
• Deep reinforcement learning for smart calibration of radio telescopes
• Methods of Error Estimation for Delay Power Spectra in $21\text{cm}$ Cosmology
• Exploring the cosmic dawn and epoch of reionization with 21cm line
• A Stimulating Explanation of the Extragalactic Radio Background
• POLAR -- I: linking the 21-cm signal from the epoch of reionization to galaxy formation
• Probing Reionization and Early Cosmic Enrichment with the MgII Forest
• A Semi-blind PCA-based Foreground Subtraction Method for 21 cm Intensity Mapping
• Probing early universe through redshifted 21-cm signal: Modelling and observational challenges
• Sky-averaged 21-cm signal extraction using multiple antennas with an SVD framework: the REACH case
• Beyond the horizon: Quantifying the full sky foreground wedge in the cylindrical power spectrum
• Accurate modelling of the Lyman-$\alpha$ coupling for the 21-cm signal, observability with NenuFAR and SKA
• Modelling the star-formation activity and ionizing properties of high-redshift galaxies
• Calibration Requirements for Epoch of Reionization 21-cm signal observations -- I. Effect of time-correlated gains
• Forecasts and Statistical Insights for Line Intensity Mapping Cross-Correlations: A Case Study with 21cm x [CII]
• Detecting the HI Power Spectrum in the Post-Reionization Universe with SKA-Low
• Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum
• The First Billion Years in Seconds: An Effective Model for the 21-cm Signal with Population III Stars
• Implications of the $z>5$ Lyman-$\alpha$ forest for the 21-cm power spectrum from the epoch of reionization
• Constraints on the state of the IGM at $z\sim 8-10$ using redshifted 21-cm observations with LOFAR
• Photoevaporation of Minihalos during Cosmic Reionization: Primordial and Metal-Enriched Halos
• Bayesian approach to constraining the properties of ionized bubbles during reionization
• On the general nature of 21cm-Lyman-$\alpha$ emitters cross-correlations during reionisation
• Persistent topology of the reionization bubble network. II: Evolution & Classification
• Generating extremely large-volume reionisation simulations
• Suppressing variance in 21-cm signal simulations during reionization
• Measurement of the Anisotropy Power Spectrum of the Radio Synchrotron Background
• Redshifted 21-cm bispectrum: Impact of the source models on the signal and the IGM physics from the Cosmic Dawn
• SKA-Low Intensity Mapping Pathfinder Updates: Deeper 21 cm Power Spectrum Limits from Improved Analysis Frameworks
• The multi-frequency angular power spectrum in parameter studies of the cosmic 21-cm signal
• CII and HI 21-cm line intensity mapping from the EoR: Impact of the light-cone effect on auto and cross-power spectra
• All Sky Modelling Requirements for Bayesian 21 cm Power Spectrum Estimation with BayesEoR
• A galaxy-free phenomenological model for the 21-cm power spectrum during reionization
• Probing the primordial Universe with 21-cm line from cosmic dawn/epoch of reionization
• pyC${}^2$Ray: A flexible and GPU-accelerated Radiative Transfer Framework for Simulating the Cosmic Epoch of Reionization
• Transient RFI environment of LOFAR-LBA at 72-75 MHz: Impact on ultra-widefield AARTFAAC Cosmic Explorer observations of the redshifted 21-cm signal
• Degree-Scale Galactic Radio Emission at 122 MHz around the North Celestial Pole with LOFAR-AARTFAAC
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator III: Foreground removal
• PINION: Physics-informed neural network for accelerating radiative transfer simulations for cosmic reionization
• Simulation-Based Inference of the sky-averaged 21-cm signal from CD-EoR with REACH
• Radio-loud fraction of z>6 quasars
• Improved upper limits on the 21-cm signal power spectrum at $z=17.0$ and $z=20.3$ from an optimal field observed with NenuFAR
• Estimation of HII Bubble Size Distribution from 21cm Power Spectrum with Artificial Neural Networks
• Cosmic mysteries and the hydrogen 21-cm line: bridging the gap with lunar observations
• 21cmFirstCLASS II. Early linear fluctuations of the 21cm signal
• A fast method of reionization parameter space exploration using GPR trained SCRIPT
• The Ultramarine Simulation: properties of dark matter haloes before redshift 5.5
• Probing the intergalactic medium during the Epoch of Reionization using 21-cm signal power spectra
• Astrophysical information from the Rayleigh-Jeans Tail of the CMB
• Efficient exploration of reionization parameters for the upcoming 21 cm observations using a photon conserving semi-numerical model SCRIPT
• Mapping discrete galaxies at cosmic dawn with 21-centimeter observations
• Thermal and Reionisation History within a Large-Volume Semi-Analytic Galaxy Formation Simulation
• Distinguishing reionization models using the largest cluster statistics of the 21-cm maps
• Predicting 21cm-line map from Lyman $\alpha$ emitter distribution with Generative Adversarial Networks
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator -- IV. Wideband analysis
• Spectral modelling of Cygnus A between 110 and 250 MHz. Impact on the LOFAR 21-cm signal power spectrum
• Effects of model incompleteness on the drift-scan calibration of radio telescopes
• Ionospheric contributions to the excess power in high-redshift 21-cm power-spectrum observations with LOFAR
• Square Kilometre Array Science Data Challenge 3a: foreground removal for an EoR experiment
• Near-field imaging of local interference in radio interferometric data: Impact on the redshifted 21 cm power spectrum
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator II: Cross-polarization power spectrum
• Validation Solutions to the Full-Sky Radio Interferometry Measurement Equation for Diffuse Emission
• Why and When to Expect Gaussian Error Distributions in Epoch of Reionization 21-cm Power Spectrum Measurements
• The mass distribution of the first stars can be determined via the 21-cm signal
• Impact of the Epoch of Reionization sources on the 21-cm bispectrum
• Delay-Weighted Calibration: Precision Calibration for 21 cm Cosmology with Resilience to Sky Model Error
• First upper limits on the 21-cm signal power spectrum of neutral hydrogen at $z=9.16$ from the LOFAR 3C196 field
• Measurements of one-point statistics in 21 cm intensity maps via foreground avoidance strategy
• Constraints on freeze-in dark matter from Lyman-$\alpha$ forest and 21-cm signal : single-field models
• A Comparative Analysis To Deal With Missing Spectral Information Caused By RFI In Cosmological HI 21CM Observations
• Sensitivity of Bayesian 21 cm power spectrum estimation to foreground model errors
• A Differentiable, End-to-End Forward Model for 21 cm Cosmology: Estimating the Foreground, Instrument, and Signal Joint Posterior
• Rapid and Late Cosmic Reionization Driven by Massive Galaxies: a Joint Analysis of Constraints from 21-cm, Lyman Line & CMB Data Sets
• Search for the Epoch of Reionisation with HERA: Upper Limits on the Closure Phase Delay Power Spectrum
• The Tracking Tapered Gridded Estimator (TTGE) for the power spectrum from drift scan observations
• Towards Optimal Foreground Mitigation Strategies for Interferometric HI Intensity Mapping in the Low-Redshift Universe
• Interpreting the HI 21-cm cosmology maps through Largest Cluster Statistics -- I: Impact of the synthetic SKA1-Low observations
• Studying the Multi-frequency Angular Power Spectrum of the Cosmic Dawn 21-cm Signal
• Linear Polarization of the 21 cm Line from the Epoch of Reionization
• Characterizing Beam Errors for Radio Interferometric Observations of Reionization
• Prospects of FRBs and Large Scale 21 cm Power Spectra in Constraining the Epoch of Reionization
• Large HI optical depth and Redshifted 21-cm signal from cosmic dawn
• Skew spectrum and smoothed skewness of 21-cm signals from epoch of reionization
• Probing the Epoch of Reionization using synergies of line intensity mapping
• Probing isocurvature perturbations with 21-cm global signal in the light of HERA result
• Photometric IGM tomography with Subaru/HSC: the large-scale structure of Ly$\alpha$ emitters and IGM transmission in the COSMOS field at $z\sim 5$
• Improvements to the Search for Cosmic Dawn Using the Long Wavelength Array
• 21-cm Constraints on Dark Matter Annihilation after an Early Matter-Dominated Era
• Constraining cosmic reionization by combining the kinetic Sunyaev-Zel'dovich and the 21 cm power spectra
• Prospects of a statistical detection of the 21-cm forest and its potential to constrain the thermal state of the neutral IGM during reionization
• Deep learning approach for identification of HII regions during reionization in 21-cm observations -- III. image recovery
• Comparison of Bayesian inference methods using the Loreli II database of hydro-radiative simulations of the 21-cm signal
• The impact of lossy data compression on the power spectrum of the high redshift 21-cm signal with LOFAR
• Ionospheric effect on the synthetic Epoch of Reionization observations with the SKA1-Low
• Robust direction-dependent gain-calibration of beam-modelling errors far from the target field
• Effects of Small-Scale Absorption Systems on Neutral Islands during the Late Epoch of Reionization
• Expanded Generalized Needlet Internal Linear Combination (eGNILC) Framework for the 21-cm Foreground Removal
• Reaching small scales with low frequency imaging: applications to the Dark Ages
• HI Intensity Mapping with the MIGHTEE Survey: First Results of the HI Power Spectrum
• Reionization relics in the cross-correlation between the Ly$\alpha$ forest and 21 cm intensity mapping in the post-reionization era
• The 21cm-galaxy cross-correlation: Realistic forecast for 21cm signal detection and reionisation constraints
• Fisher matrix forecasts on the astrophysics of galaxies during the epoch of reionisation from the 21-cm power spectra
• Synthetic Observations with the Square Kilometre Array (SKA) -- development towards an end-to-end pipeline
• Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-Point Statistics
• Impact of Calibration and Position Errors on Astrophysical Parameters of the HI 21cm Signal
• From ANN to BNN: Inferring Reionization Parameters using Uncertainty-aware Emulators of 21-cm Summaries
• Epoch of Reionization Power Spectrum Limits from Murchison Widefield Array Data Targeted at EoR1 Field
• The signature of galaxy formation models in the power spectrum of the hydrogen 21cm line during reionization
• Constraints on the galaxy formation models during epoch of reionization with high redshift observations
• Particle production during inflation: constraints expected from redshifted 21 cm observations from the epoch of reionization
• Extracting the Epoch of Reionization Signal with 3D U-Net Neural Networks Using Data-driven Systematic Effect Model
• An Alcock-Paczynski Test on Reionization Bubbles for Cosmology
• The Optical Depth of Foregrounds for the Highest Redshift 21 cm Signals
• Calibration requirement for Epoch of Reionization 21-cm signal observation -- III. Bias and variance in uGMRT ELAIS-N1 field power spectrum
• The Evolving Power Spectrum for the light cone Epoch of Reionization (EoR) 21-cm signal
• Exploring Machine Learning Regression Models for Advancing Foreground Mitigation and Global 21cm Signal Parameter Extraction
• The impact of lunar topography on the 21-cm power spectrum for grid-based arrays : Insights for the Dark-ages EXplorer (DEX)
• Cosmic backgrounds from the radio to the far-infrared: recent results and perspectives from cosmological and astrophysical surveys
• The Effect of Large Optical Depths on the Non-Gaussian 21-cm signal from Cosmic Dawn
• Impact of anisotropic photon emission from sources during the epoch of reionisation
• Mapping neutral islands during end stages of reionization with photometric intergalactic medium tomography
• The haloes that reionized the Universe
• Radiative transfer of 21-cm line through ionised cavities in an expanding universe
• CHILES VII: Deep Imaging for the CHILES project, a SKA prototype
• First Light: Switching on Stars at the Dawn of Time
• Interpreting the HI 21-cm cosmology maps through Largest Cluster Statistics. Part II. Impact of the realistic foreground and instrumental noise on synthetic SKA1-Low observations
• Direct reconstruction of the Reionization history from 21cm 2D Power Spectra
• Mitigating incoherent excess variance in high-redshift 21 cm observations with multi-output cross-Gaussian process regression
• The 21-cm signal from the Cosmic Dawn: metallicity dependence of high mass X-ray binaries
• Simulation based inference of the ionization history from the 2D 21 cm power spectrum
• BayesEoR: Bayesian 21-cm Power Spectrum Estimation from Interferometric Visibilities
• Power spectrum multipoles and clustering wedges during the Epoch of Reionization
• An Introduction to Single-Antenna Radio Astronomical Polarimetry
• Bayes-SCF: A Bayesian filter to mitigate foreground leakage in the 21-cm power spectrum
• A New Boundary Condition on Reionization
• Mitigating gain calibration errors from EoR observations with SKA1-Low AA*
• CosmoUiT: A Vision Transformer-UNet Hybrid for Fast and Accurate Emulation of 21-cm Maps from the Epoch of Reionization
• The Correlation Calibration of PAPER-64 data
• Beyond the Power Spectrum: A New Framework for Non-Stationary Fields with Applications to Light-Cone Effects in Line Intensity Mapping