59 citations · 210 across the 18 of their papers we have counts for
18 papers
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…
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…
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…
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),…
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…
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…
Near-field imaging of local interference in radio interferometric data: Impact on the redshifted 21 cm power spectrum
S. Munshi, F. G. Mertens, L. V. E. Koopmans +24
Radio-frequency interference (RFI) is a major systematic limitation in radio astronomy, particularly for science cases requiring high sensitivity, such as 21 cm cosmology. Traditio…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
Accurate modelling of the Lyman- coupling for the 21-cm signal, observability with NenuFAR and SKA
Benoit Semelin, Romain Mériot, Florent Mertens +6
The measurement of the cm signal from the Cosmic Dawn is a major goal for several existing and upcoming radio interferometers such as NenuFAR and the SKA. During this era befo…