Andrei Mesinger
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View article: Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-point Statistics
Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-point Statistics Open
Measuring one-point statistics in redshifted 21 cm intensity maps offers an opportunity to explore non-Gaussian features of the early Universe. We assess the impact of instrumental effects on measurements made with the Hydrogen Epoch of Re…
View article: Updated dark pixel fraction constraints on reionization’s end from the Lyman-series forests of XQR−30
Updated dark pixel fraction constraints on reionization’s end from the Lyman-series forests of XQR−30 Open
The fraction of ‘dark pixels’ in the Ly$\alpha$ and other Lyman-series forests at $z\sim 5$–6 provides a powerful constraint on the end of the reionization process. Any spectral region showing transmission must be highly ionized, while dar…
View article: Sample variance denoising in cylindrical 21 cm power spectra
Sample variance denoising in cylindrical 21 cm power spectra Open
State-of-the-art simulations of re-ionisation-era 21 cm signal have limited volumes, generally orders of magnitude smaller than observations. Consequently, the Fourier modes in common between simulation and observation have limited overlap…
View article: Efficient simulation of discrete galaxy populations and associated radiation fields over the first billion years
Efficient simulation of discrete galaxy populations and associated radiation fields over the first billion years Open
Understanding the epochs of cosmic dawn and reionisation requires us to leverage multi-wavelength and multi-tracer observations, with each dataset providing a complementary piece of the puzzle. To interpret these data, we updated the publi…
View article: Sample Variance Denoising in Cylindrical 21-cm Power Spectra
Sample Variance Denoising in Cylindrical 21-cm Power Spectra Open
State-of-the-art simulations of reionisation-era 21-cm signal have limited volumes, generally orders of magnitude smaller than observations. Consequently, the Fourier modes in common between simulation and observation have limited overlap,…
View article: Investigating mutual coupling in the hydrogen epoch of reionization array and mitigating its effects on the 21-cm power spectrum
Investigating mutual coupling in the hydrogen epoch of reionization array and mitigating its effects on the 21-cm power spectrum Open
Interferometric experiments designed to detect the highly redshifted 21-cm signal from neutral hydrogen are producing increasingly stringent constraints on the 21-cm power spectrum, but some k-modes remain systematics-dominated. Mutual cou…
View article: Mapping reionization bubbles in JWST era
Mapping reionization bubbles in JWST era Open
The James Webb Space Telescope (JWST) is discovering an increasing number of galaxies well into the early stages of the epoch of reionization (EoR). Many of these galaxies are clustered with strong Lyman-alpha (Ly α ) emission, which indic…
View article: Detecting galaxy – 21-cm cross-correlation during reionization
Detecting galaxy – 21-cm cross-correlation during reionization Open
The cosmic 21-cm signal promises to revolutionize studies of the Epoch of Reionization (EoR). Radio interferometers are aiming for a preliminary, low signal-to-noise (S/N) detection of the 21-cm power spectrum. Cross-correlating 21-cm with…
View article: The EDGES measurement disfavors an excess radio background during the cosmic dawn
The EDGES measurement disfavors an excess radio background during the cosmic dawn Open
In 2018 the EDGES experiment claimed the first detection of the global cosmic 21 cm signal, which featured an absorption trough centered around z ∼ 17 with a depth of approximately −500 mK. This amplitude is deeper than the standard predic…
View article: StratLearn-z: Improved photo- <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mi>z</a:mi> </a:math> estimation from spectroscopic data subject to selection effects
StratLearn-z: Improved photo- z estimation from spectroscopic data subject to selection effects Open
A precise measurement of photometric redshifts (photo-z) is crucial for the success of modern photometric galaxy surveys. Machine learning (ML) methods show great promise in this context, but suffer from covariate shift in training sets du…
View article: Erratum: “The Impact of Cosmic Variance on Inferences of Global Neutral Fraction Derived from Ly<i>α</i> Luminosity Functions during Reionization” (2023, ApJ, 953, 29)
Erratum: “The Impact of Cosmic Variance on Inferences of Global Neutral Fraction Derived from Ly<i>α</i> Luminosity Functions during Reionization” (2023, ApJ, 953, 29) Open
View article: Mapping reionization bubbles in JWST era
Mapping reionization bubbles in JWST era Open
Context. Ionized bubble sizes during reionization trace physical properties of the first galaxies. JWST's ability to spectroscopically confirm and measure Lyman-alpha (Ly α ) emission in sub-L ★ galaxies makes it possible to map to map ion…
View article: Impacts and Statistical Mitigation of Missing Data on the 21 cm Power Spectrum: A Case Study with the Hydrogen Epoch of Reionization Array
Impacts and Statistical Mitigation of Missing Data on the 21 cm Power Spectrum: A Case Study with the Hydrogen Epoch of Reionization Array Open
The precise characterization and mitigation of systematic effects is one of the biggest roadblocks impeding the detection of the fluctuations of cosmological 21 cm signals. Missing data in radio cosmological experiments, often due to radio…
View article: Mapping reionization bubbles in the JWST era II: inferring the position and characteristic size of individual bubbles
Mapping reionization bubbles in the JWST era II: inferring the position and characteristic size of individual bubbles Open
The James Webb Space Telescope (JWST) is discovering an increasing number of galaxies well into the early stages of the Epoch of Reionization (EoR). Many of these galaxies are clustered with strong Lyman alpha (Ly$α$) emission, motivating …
View article: Global 21 cm signal: a promising probe of primordial features
Global 21 cm signal: a promising probe of primordial features Open
Inflationary models that involve bursts of particle production generate bump-like features in the primordial power spectrum of density perturbations. These features influence the evolution of density fluctuations, leaving their unique sign…
View article: Percent-level timing of reionisation: Self-consistent, implicit-likelihood inference from XQR-30+ Lyα forest data
Percent-level timing of reionisation: Self-consistent, implicit-likelihood inference from XQR-30+ Lyα forest data Open
The Lyman alpha (Ly $\alpha$ ) forest in the spectra of $z\gt5$ quasars provides a powerful probe of the late stages of the epoch of reionisation (EoR). With the recent advent of exquisite datasets such as XQR-30, many models have struggle…
View article: <tt>matvis</tt>: a matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays
matvis: a matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays Open
Detection of the faint 21 cm line emission from the Cosmic Dawn and Epoch of Reionization will require not only exquisite control over instrumental calibration and systematics to achieve the necessary dynamic range of observations but also…
View article: Percent-level timing of reionization: self-consistent, implicit-likelihood inference from XQR-30+ Ly$α$ forest data
Percent-level timing of reionization: self-consistent, implicit-likelihood inference from XQR-30+ Ly$α$ forest data Open
The Lyman alpha (Lya) forest in the spectra of z>5 quasars provides a powerful probe of the late stages of the Epoch of Reionization (EoR). With the recent advent of exquisite datasets such as XQR-30, many models have struggled to reproduc…
View article: The EDGES measurement disfavors an excess radio background during the cosmic dawn
The EDGES measurement disfavors an excess radio background during the cosmic dawn Open
In 2018 the EDGES experiment claimed the first detection of the global cosmic 21cm signal, which featured an absorption trough centered around $z \sim 17$ with a depth of approximately -500mK. This amplitude is deeper than the standard pre…
View article: A demonstration of the effect of fringe-rate filtering in the hydrogen epoch of reionization array delay power spectrum pipeline
A demonstration of the effect of fringe-rate filtering in the hydrogen epoch of reionization array delay power spectrum pipeline Open
Radio interferometers targeting the 21cm brightness temperature fluctuations at high redshift are subject to systematic effects that operate over a range of different time-scales. These can be isolated by designing appropriate Fourier filt…
View article: Mapping reionization bubbles in the JWST era I: empirical edge detection with Lyman alpha emission from galaxies
Mapping reionization bubbles in the JWST era I: empirical edge detection with Lyman alpha emission from galaxies Open
Ionized bubble sizes during reionization trace physical properties of the first galaxies. JWST's ability to spectroscopically confirm and measure Lyman-alpha (Ly$α$) emission in sub-L* galaxies opens the door to mapping ionized bubbles in …
View article: The importance of stochasticity in determining galaxy emissivities and UV LFs during cosmic dawn and reionization
The importance of stochasticity in determining galaxy emissivities and UV LFs during cosmic dawn and reionization Open
The stochastic nature of star formation and photon propagation in high-redshift galaxies can result in sizable galaxy-to-galaxy scatter in their properties. Ignoring this scatter by assuming mean quantities can bias estimates of their emis…
View article: Mitigating calibration errors from mutual coupling with time-domain filtering of 21 cm cosmological radio observations
Mitigating calibration errors from mutual coupling with time-domain filtering of 21 cm cosmological radio observations Open
The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionization (EoR). This has led to the construction of low-frequency radio interferometric arrays, such as the Hydrogen Epoch of Reioni…
View article: StratLearn-z: Improved photo-$z$ estimation from spectroscopic data subject to selection effects
StratLearn-z: Improved photo-$z$ estimation from spectroscopic data subject to selection effects Open
A precise measurement of photometric redshifts (photo-z) is key for the success of modern photometric galaxy surveys. Machine learning (ML) methods show great promise in this context, but suffer from covariate shift (CS) in training sets d…
View article: Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data
Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data Open
Observations with radio arrays that target the 21-cm signal originating from the early Universe suffer from a variety of systematic effects. An important class of these are reflections and spurious couplings between antennas. We apply a Ha…
View article: Exploring the role of the halo-mass function for inferring astrophysical parameters during reionization
Exploring the role of the halo-mass function for inferring astrophysical parameters during reionization Open
Detecting the 21-cm signal at $z\gtrsim 6$ will reveal insights into the properties of the first galaxies responsible for driving reionization. To extract this information, we perform parameter inference with three-dimensional simulations …
View article: Inferring astrophysical parameters using the 2D cylindrical power spectrum from reionization
Inferring astrophysical parameters using the 2D cylindrical power spectrum from reionization Open
Enlightening our understanding of the first galaxies responsible for driving reionization requires detecting the 21-cm signal from neutral hydrogen. Interpreting the wealth of information embedded in this signal requires Bayesian inference…
View article: Blind QSO reconstruction challenge: exploring methods to reconstruct the Ly α emission line of QSOs
Blind QSO reconstruction challenge: exploring methods to reconstruct the Ly α emission line of QSOs Open
Reconstructing the intrinsic Ly $\alpha$ line flux from high-z QSOs can place constraints on the neutral hydrogen content of the intergalactic medium during reionization. There are now $\gtrsim 10$ different Ly $\alpha$ reconstruction pipe…
View article: Correction to: <scp>21cmemu</scp>: an emulator of <scp>21cmfast</scp> summary observables
Correction to: <span>21cmemu</span>: an emulator of <span>21cmfast</span> summary observables Open
In the HERA sixth season forecast of Breitman et al. ( 2024 ), the standard deviation calculated with the 21 CMSENSE code was misread as the variance when performing inference.This resulted in an o v erly optimistic inference forecast in s…
View article: Direct Optimal Mapping Image Power Spectrum and its Window Functions
Direct Optimal Mapping Image Power Spectrum and its Window Functions Open
The key to detecting neutral hydrogen during the epoch of reionization (EoR) is to separate the cosmological signal from the dominating foreground radiation. We developed direct optimal mapping (DOM) to map interferometric visibilities; it…