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Related papers: Detecting 21 cm EoR Signal using Drift Scans: Corr…

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The redshifted 21cm line of neutral hydrogen (Hi), potentially observable at low radio frequencies (~50-200 MHz), is a promising probe of the physical conditions of the inter-galactic medium during Cosmic Dawn and the Epoch of Reionisation…

Precise measurements in optical and atomic systems often rely on differential interferometry. This method allows to handle large and correlated phase noise contributions -- such as environmental vibrations, thermal fluctuations, or…

Quantum Physics · Physics 2025-03-25 Luca Pezzè , Andrea Santoni , Chiara Mazzinghi , Marco Fattori , Augusto Smerzi

We propose the HI 21-cm power spectrum from the post-reionization epoch as a probe of a cosmological model with decaying dark matter particles. The unstable particles are assumed to undergo a 2-body decay into a massless and massive…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-12 Mohit Yadav , Tapomoy Guha Sarkar

Foreground removal is the most important step in detecting the large-scale redshifted HI 21-cm signal. Modelling foreground spectra is challenging and is further complicated by the chromatic response of the telescope. We present a…

Instrumentation and Methods for Astrophysics · Physics 2017-07-19 Visweshwar Ram Marthi , Suman Chatterjee , Jayaram Chengalur , Somnath Bharadwaj

For the GMRT, we calculate the expected signal from redshifted HI emission at two frequency bands centered at 610 and 325 MHz. The study focuses on the visibility-visibility cross-correlations, proposed earlier as the optimal statistical…

Astrophysics · Physics 2009-11-10 Somnath Bharadwaj , Sanjay K. Pande

We use high resolution hydrodynamical simulations to study the contribution to the X-ray background from high-$z$ energetic sources, such as X-ray binaries, accreting nuclear black holes and shock heated interstellar medium. Adopting the…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-25 Q. Ma , B. Ciardi , M. B. Eide , K. Helgason

We present the early science results from a blind search of the extragalactic HI 21-cm absorption lines at z $\leqslant$ 0.09 with the drift-scan observation of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We carried…

The Heliospheric Imagers (HI) on board the two spacecraft of the Solar Terrestrial Relations Observatory (STEREO) provided white-light images of transients in the solar wind from dual perspectives from 2007 to 2014. In this paper, we…

Solar and Stellar Astrophysics · Physics 2018-09-12 Xiaolei Li , Yuming Wang , Rui Liu , Chenglong Shen , Quanhao Zhang , Bin Zhuang , Jiajia Liu , Yutian Chi

The power spectrum of redshifted 21 cm emission brightness temperature fluctuations is a powerful probe of the Epoch of Reionization (EoR). However, bright foreground emission presents a significant impediment to its unbiased recovery from…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-31 Peter H. Sims , Jonathan C. Pober

Radio interferometers, such as the Low-Frequency Array and the future Square Kilometre Array, are attempting to measure the spherically averaged 21-cm power spectrum from the Epoch of Reionization. Understanding of the dominant physical…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-01 Ivelin Georgiev , Garrelt Mellema , Sambit K. Giri , Rajesh Mondal

Radio interferometers designed to probe the 21cm signal from Cosmic Dawn and the Epoch of Reionisation must contend with systematic effects that make it difficult to achieve sufficient dynamic range to separate the 21cm signal from…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-24 Fraser Kennedy , Philip Bull , Michael Wilensky , Jacob Burba , Samir Choudhuri

The method of time delay interferometry (TDI) is proposed to cancel the laser noise in space-borne gravitational-wave detectors. Among all different TDI combinations, the most commonly used ones are the orthogonal channels A, E and T, where…

Astrophysics of Galaxies · Physics 2023-08-09 Zheng-Cheng Liang , Zhi-Yuan Li , Jun Cheng , En-Kun Li , Jian-dong Zhang , Yi-Ming Hu

In binaural audio synthesis, aligning head-related impulse responses (HRIRs) in time has been an important pre-processing step, enabling accurate spatial interpolation and efficient data compression. The maximum correlation time delay…

Sound · Computer Science 2024-10-22 Chin-Yun Yu , Johan Pauwels , György Fazekas

In the marine environment, many fields have fluctuations over a large range of different spatial and temporal scales. These quantities can be nonlinear \red{and} non-stationary, and often interact with each other. A good method to study the…

Atmospheric and Oceanic Physics · Physics 2014-01-20 Y. X. Huang , Francois G. Schmitt

We present a comprehensive analysis of the 21 cm intensity mapping (IM) data from the Tianlai Cylinder Pathfinder Array (TCPA), focusing on multi-scale foreground mitigation and three-dimensional power spectrum estimation. Utilizing 20 days…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-01 Yikai Deng , Shifan Zuo , Jixia Li , Yougang Wang , Xuelei Chen

We examine the Detrended Fluctuation Analysis (DFA), which is a well-established method for the detection of long-range correlations in time series. We show that deviations from scaling that appear at small time scales become stronger in…

Statistical Mechanics · Physics 2009-11-07 Jan W. Kantelhardt , Eva Koscielny-Bunde , Henio H. A. Rego , Shlomo Havlin , Armin Bunde

The redshifted 21-cm signal from neutral hydrogen (HI) in the intergalactic medium (IGM) is a powerful probe of the Epoch of Reionization (EoR). Owing to the complex growth and morphology of ionized regions, the 21-cm brightness-temperature…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-19 Vishrut Pandya , Leon Noble , Suman Majumdar , Debanjan Sarkar , Mohd Kamran , Abhirup Datta

The epoch of reionization (EoR) 21-cm signal is expected to be highly non-Gaussian in nature and this non-Gaussianity is also expected to evolve with the progressing state of reionization. Therefore the signal will be correlated between…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-14 Suman Majumdar , Jonathan R. Pritchard , Rajesh Mondal , Catherine A. Watkinson , Somnath Bharadwaj , Garrelt Mellema

Measurement of the 21cm hyperfine transition of neutral hydrogen provides a unique probe of the epoch of reionization and the Dark Ages. Three major mechanisms are believed to dominate the radiation process: emission from neutral hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Qian Zheng

Contamination due to foregrounds (Galactic and Extra-galactic), calibration errors and ionospheric effects pose major challenges in detection of the cosmic 21 cm signal in various Epoch of Reionization (EoR) experiments. We present the…

Instrumentation and Methods for Astrophysics · Physics 2018-05-15 B. K. Gehlot , L. V. E. Koopmans , A. G. de Bruyn , S. Zaroubi , M. A. Brentjens , K. M. B. Asad , M. Hatef , V. Jelic , M. Mevius , A. R. Offringa , V. N. Pandey , S. Yatawatta
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