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The 21-cm brightness temperature fluctuation from the Dark Ages ($z \simeq 30-100$) will allow us to probe the inflationary epoch on very small scales ($>0.1 \, \mbox{Mpc}^{-1}$), inaccessible to cosmic microwave background experiments.…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-28 Giorgio Orlando , Thomas Flöss , P. Daniel Meerburg , Joseph Silk

In a companion paper, we presented BayesCal, a mathematical formalism for mitigating sky-model incompleteness in interferometric calibration. In this paper, we demonstrate the use of BayesCal to calibrate the degenerate gain parameters of…

Instrumentation and Methods for Astrophysics · Physics 2022-07-20 Peter H. Sims , Jonathan C. Pober , Jonathan L. Sievers

Chemical multisensor devices need calibration algorithms to estimate gas concentrations. Their possible adoption as indicative air quality measurements devices poses new challenges due to the need to operate in continuous monitoring modes…

Artificial Intelligence · Computer Science 2020-02-14 S. De Vito , E. Esposito , M. Salvato , O. Popoola , F. Formisano , R. Jones , G. Di Francia

We have constructed a Bayesian neural network able of retrieving tropospheric temperature profiles from rotational Raman-scatter measurements of nitrogen and oxygen and applied it to measurements taken by the RAman Lidar for Meteorological…

Atmospheric and Oceanic Physics · Physics 2023-04-12 Ghazal Farhani , Giovanni Martucci , Tyler Roberts , Alexander Haefele , Robert J. Sica

The Epoch of Reionization (EoR) and Cosmic Dawn (CD) are pivotal stages during the first billion years of the universe, exerting a significant influence on the development of cosmic structure. The detection of the redshifted 21-cm signal…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Anshuman Tripathi , Abhirup Datta , Aishrila Mazumder , Suman Majumdar

The aim of the new generation of radio synthesis arrays such as LOFAR and SKA is to achieve much higher sensitivity, resolution and frequency coverage than what is available now, especially at low frequencies. To accomplish this goal, the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 S. Kazemi , S. Yatawatta , S. Zaroubi , A. G. de Bruyn , L. V. E. Koopmans , J. Noordam

The resonance scattering of Ly$\alpha$ photons with neutral hydrogen atoms in the intergalactic medium not only couples the spin temperature to the kinetic temperature but also leads to a heating of the gas. We investigate the impact of…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Raghunath Ghara , Garrelt Mellema

Optical quantum computing, as well as quantum communication and sensing technology based on quantum correlations are in preparation. These require photodiodes for the detection of about 10^16 photons per second with close to perfect quantum…

Quantum Physics · Physics 2026-02-16 Leif Albers , Jan-Malte Michaelsen , Roman Schnabel

We introduce CALAMITY, a precision bandpass calibration method for radio interferometry. CALAMITY can solve for direction independent gains with arbitrary frequency structure to the high precision required for 21 cm cosmology with minimal…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-01 Aaron Ewall-Wice , Joshua S. Dillon , Bharat Gehlot , Aaron Parsons , Tyler Cox , Daniel C. Jacobs

Searching for gravitational-wave signals is a challenging and computationally intensive endeavor undertaken by multiple independent analysis pipelines. While detection depends only on observed noisy data, it is sometimes inconsistently…

General Relativity and Quantum Cosmology · Physics 2024-03-15 Matthew Mould , Christopher J. Moore , Davide Gerosa

Observations of 21cm line from neutral hydrogen promise to be an exciting new probe of astrophysics and cosmology during the Cosmic Dawn and through the Epoch of Reionization (EoR) to when dark energy accelerates the expansion of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-24 Tyler A. Cox , Aaron R. Parsons , Joshua S. Dillon , Aaron Ewall-Wice , Robert Pascua

We present here 21 cm predictions from high dynamic range simulations for a range of reionization histories that have been tested against available Lyman-alpha and CMB data. We assess the observability of the predicted spatial 21 cm…

Astrophysics of Galaxies · Physics 2016-09-13 Girish Kulkarni , Tirthankar Roy Choudhury , Ewald Puchwein , Martin G. Haehnelt

We revisit the global 21cm signal calculation incorporating a possible radio background at early times, and find that the global 21cm signal shows a much stronger absorption feature, which could enhance detection prospects for future 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 Chang Feng , Gilbert Holder

21 cm cosmology, the statistical observation of the high redshift universe using the hyperfine transition of neutral hydrogen, has the potential to revolutionize our understanding of cosmology and the astrophysical processes that underlie…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-10 Joshua S. Dillon

The cross-correlation between fluctuations in the electron scattering optical depth $\tau_{\rm es}$ as probed by future Cosmic Microwave Background (CMB) experiments, and fluctuations in the 21cm differential brightness temperature $\Delta…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-07 Anirban Roy , Andrea Lapi , David Spergel , Soumen Basak , Carlo Baccigalupi

The upcoming radio interferometer Square Kilometre Array (SKA) is expected to directly detect the redshifted 21-cm signal from the neutral hydrogen present during the Cosmic Dawn. Temperature fluctuations from X-ray heating of the neutral…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-15 Hannah E. Ross , Keri L. Dixon , Raghunath Ghara , Ilian T. Iliev , Garrelt Mellema

This paper presents a polarization calibration method applied to a microwave polarimeter demonstrator based on a near-infrared (NIR) frequency up-conversion stage that allows both optical correlation and signal detection at a wavelength of…

Instrumentation and Methods for Astrophysics · Physics 2022-10-25 Francisco J. Casas , Patricio Vielva , R. Belen Barreiro , Enrique Martínez-González , G. Pascual-Cisneros

We re-examine the role of collisions in decoupling the HI 21-cm spin temperature from the cosmic microwave background (CMB). The cross section for de-exciting the 21-cm trasition in collisions with free electrons is more than 10 times…

Astrophysics · Physics 2009-11-10 Adi Nusser

Detecting and characterizing the Epoch of Reionization and Cosmic Dawn via the redshifted 21-cm hyperfine line of neutral hydrogen will revolutionize the study of the formation of the first stars, galaxies, black holes and intergalactic gas…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 F. G. Mertens , A. Ghosh , L. V. E. Koopmans

Bayesian inference is a widely used technique for real-time characterization of quantum systems. It excels in experimental characterization in the low data regime, and when the measurements have degrees of freedom. A decisive factor for its…

Quantum Physics · Physics 2025-07-10 Alexandra Ramôa , Raffaele Santagati , Nathan Wiebe