activity
20202026
most citedFirst upper limits on the 21 cm signal power spectrum from cosmic dawn from one night of observations with NenuFAR

59 citations · 243 across the 23 of their papers we have counts for

collaborators

24 papers

astro-ph.CO2026

Overview of 21cm Experiments at high redshift with SKAO

CD Science Working Group, Gianni Bernardi, Daniela Breitman +81

We provide an overview of the eight SKAO Science Book chapters that motivate the Epoch of Reionisation and Cosmic Dawn experiments with SKA-Low. We describe the individual SKA-Low…

astro-ph.IM2026

Development of TIFUUN: Terahertz Integral Field Units with Universal Nanotechnology

Akira Endo, Tom J. L. C. Bakx, Jochem J. A. Baselmans +50

TIFUUN (THz Integral Field Units with Universal Nanotechnology) is an ultra-wideband mm-submm wave imaging spectrometer that capitalizes on the highly scalable integrated supercond…

astro-ph.IM2026

gateau: an observation simulator for ground-based submillimeter astronomy with integral field units and kinetic inductance detectors

A. Moerman, N. Soshnin, S. A. Brackenhoff +7

Submillimeter (submm) integral field units (IFUs) utilising kinetic inductance detectors (KIDs) are a promising instrument architecture for the study of galaxies, galaxy clusters,…

astro-ph.IM2025★ 1 cited

The impact of lunar topography on the 21-cm power spectrum for grid-based arrays : Insights for the Dark-ages EXplorer (DEX)

S. Ghosh, L. V. E. Koopmans, C. Brinkerink +17

The Dark Ages (DA) provides a crucial window into the physics of the infant Universe, with the 21-cm signal offering the only direct probe for mapping out the three-dimensional dis…

astro-ph.CO2025★ 11 cited

Improved upper limits on the 21-cm signal power spectrum at and from an optimal field observed with NenuFAR

S. Munshi, F. G. Mertens, J. K. Chege +19

We report the deepest upper limits to date on the power spectrum of the 21-cm signal during the Cosmic Dawn (redshifts: ), using four nights of observations with NenuFAR. The…

astro-ph.CO2025

Mitigating incoherent excess variance in high-redshift 21 cm observations with multi-output cross-Gaussian process regression

S. Munshi, L. V. E. Koopmans, F. G. Mertens +8

Systematic effects that limit the achievable sensitivity of current low-frequency radio telescopes to the 21 cm signal are among the foremost challenges in observational 21 cm cosm…

astro-ph.CO2025★ 14 cited

Constraints on the state of the IGM at using redshifted 21-cm observations with LOFAR

R. Ghara, S. Zaroubi, B. Ciardi +21

The power spectra of the redshifted 21-cm signal from the Epoch of Reionization (EoR) contain information about the ionization and thermal states of the intergalactic medium (IGM),…

astro-ph.CO2025★ 7 cited

First upper limits on the 21-cm signal power spectrum of neutral hydrogen at from the LOFAR 3C196 field

E. Ceccotti, A. R. Offringa, F. G. Mertens +16

The redshifted 21-cm signal of neutral hydrogen from the Epoch of Reionization (EoR) can potentially be detected using low-frequency radio instruments such as the Low-Frequency Arr…

astro-ph.CO2025★ 27 cited

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

F. G. Mertens, M. Mevius, L. V. E. Koopmans +20

We present new upper limits on the 21-cm signal power spectrum from the Epoch of Reionization (EoR), at redshifts , based on reprocessed obse…

astro-ph.CO2025★ 1 cited

The impact of diffuse Galactic emission on direction-independent gain calibration in high-redshift 21 cm observations

C. Höfer, L. V. E. Koopmans, S. A. Brackenhoff +7

This study examines the impact of diffuse Galactic emission (DGE) on sky-based direction-independent (DI) gain calibration using realistic forward simulations of Low-Frequency Arra…

astro-ph.IM2025★ 4 cited

Robust direction-dependent gain-calibration of beam-modelling errors far from the target field

S. A. Brackenhoff, A. R. Offringa, M. Mevius +8

Many astronomical questions require deep, wide-field observations at low radio frequencies. Phased arrays like LOFAR and SKA-low are designed for this, but have inherently unstable…

astro-ph.IM2025★ 9 cited

Square Kilometre Array Science Data Challenge 3a: foreground removal for an EoR experiment

A. Bonaldi, P. Hartley, R. Braun +179

We present and analyse the results of the Science data challenge 3a (SDC3a, https://sdc3.skao.int/challenges/foregrounds), an EoR foreground-removal community-wide exercise organis…

astro-ph.CO2025★ 9 cited

Spectral modelling of Cygnus A between 110 and 250 MHz. Impact on the LOFAR 21-cm signal power spectrum

E. Ceccotti, A. R. Offringa, L. V. E. Koopmans +15

Studying the redshifted 21-cm signal from the the neutral hydrogen during the Epoch of Reionization and Cosmic Dawn is fundamental for understanding the physics of the early univer…

astro-ph.IM2024★ 2 cited

Extracting the Epoch of Reionization Signal with 3D U-Net Neural Networks Using Data-driven Systematic Effect Model

Li-Yang Gao, Léon V. E. Koopmans, Florent G. Mertens +11

Neutral hydrogen (HI) serves as a crucial probe for the Cosmic Dawn and the Epoch of Reionization (EoR). Actual observations of the 21-cm signal often encounter challenges such as…

astro-ph.CO2024★ 9 cited

Ionospheric contributions to the excess power in high-redshift 21-cm power-spectrum observations with LOFAR

S. A. Brackenhoff, M. Mevius, L. V. E. Koopmans +9

The turbulent ionosphere causes phase shifts to incoming radio waves on a broad range of temporal and spatial scales. When an interferometer is not sufficiently calibrated for the…

astro-ph.CO2024★ 4 cited

The impact of lossy data compression on the power spectrum of the high redshift 21-cm signal with LOFAR

J. K. Chege, L. V. E. Koopmans, A. R. Offringa +8

Current radio interferometers output multi-petabyte-scale volumes of data per year making the storage, transfer, and processing of this data a sizeable challenge. This challenge is…

astro-ph.CO2024★ 15 cited

Beyond the horizon: Quantifying the full sky foreground wedge in the cylindrical power spectrum

S. Munshi, F. G. Mertens, L. V. E. Koopmans +8

One of the main obstacles preventing the detection of the redshifted 21-cm signal from neutral hydrogen in the early Universe is the astrophysical foreground emission, which is sev…

astro-ph.CO2023★ 12 cited

Transient RFI environment of LOFAR-LBA at 72-75 MHz: Impact on ultra-widefield AARTFAAC Cosmic Explorer observations of the redshifted 21-cm signal

B. K. Gehlot, L. V. E. Koopmans, S. A. Brackenhoff +13

Measurement of the redshifted 21-cm signal of neutral hydrogen from the Cosmic Dawn (CD) and Epoch of Reionisation (EoR) promises to unveil a wealth of information about the astrop…

astro-ph.CO2023★ 59 cited

First upper limits on the 21 cm signal power spectrum from cosmic dawn from one night of observations with NenuFAR

S. Munshi, F. G. Mertens, L. V. E. Koopmans +24

The redshifted 21 cm signal from neutral hydrogen is a direct probe of the physics of the early universe and has been an important science driver of many present and upcoming radio…

astro-ph.IM2023★ 4 cited

A novel radio imaging method for physical spectral index modelling

E. Ceccotti, A. R. Offringa, L. V. E. Koopmans +9

We present a new method, called "forced-spectrum fitting", for physically-based spectral modelling of radio sources during deconvolution. This improves upon current common deconvol…

astro-ph.CO2022★ 24 cited

Assessing the impact of two independent direction-dependent calibration algorithms on the LOFAR 21-cm signal power spectrum

H. Gan, F. G. Mertens, L. V. E. Koopmans +11

Detecting the 21-cm signal from the Epoch of Reionisation (EoR) is challenging due to the strong astrophysical foregrounds, ionospheric effects, radio frequency interference and in…

astro-ph.IM2021★ 20 cited

DESHIMA 2.0: development of an integrated superconducting spectrometer for science-grade astronomical observations

Akio Taniguchi, Tom J. L. C. Bakx, Jochem J. A. Baselmans +32

Integrated superconducting spectrometer (ISS) technology will enable ultra-wideband, integral-field spectroscopy for (sub)millimeter-wave astronomy, in particular, for uncovering t…

astro-ph.IM2021★ 2 cited

TiEMPO: Open-source time-dependent end-to-end model for simulating ground-based submillimeter astronomical observations

Esmee Huijten, Yannick Roelvink, Stefanie A. Brackenhoff +14

The next technological breakthrough in millimeter-submillimeter astronomy is 3D imaging spectrometry with wide instantaneous spectral bandwidths and wide fields of view. The total…

astro-ph.SR2020★ 9 cited

Detection of polarization neutral points in observations of the combined corona and sky during the 21 August 2017 total solar eclipse

Frans Snik, Steven P. Bos, Stefanie A. Brackenhoff +7

We report the results of polarimetric observations of the total solar eclipse of 21 August 2017 from Rexburg, Idaho (USA). We use three synchronized DSLR cameras with polarization…