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21cm-galaxy cross-correlation will play a key role in confirming the cosmological 21cm signal. We investigate which survey configurations detect the 21cm-LAE cross-correlation signal, and assess its ability to distinguish reionisation…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-18 Anne Hutter , Caroline Heneka

One approach to extracting the global 21-cm signal from total-power measurements at low radio frequencies is to parametrize the different contributions to the data and then fit for these parameters. We examine parametrizations of the 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-04 Geraint J. A. Harker , Jordan Mirocha , Jack O. Burns , Jonathan R. Pritchard

ATLAS (Asteroid Terrestrial Last Alert System) is a time-domain survey using four telescopes, covering the entire sky. It has observed over 10,000 spectroscopically confirmed Type Ia supernovae (SNe~Ia), with thousands of cosmology-grade…

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

Current and upcoming 21-cm experiments will soon be able to map 21-cm spatial fluctuations in three dimensions for a wide range of redshifts. However, bright foreground contamination and the nature of radio interferometry create significant…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 Shu-Fan Chen , Kai-Feng Chen , Cora Dvorkin

Foreground subtraction is the biggest challenge for future redshifted 21 cm observations to probe reionization. We use a short GMRT observation at 153 MHz to characterize the statistical properties of the background radiation across ~ one…

Astrophysics · Physics 2009-11-13 SK. Saiyad Ali , Somnath Bharadwaj , Jayaram N. Chengalur

The redshifted 21 cm line signal is a powerful probe of the cosmic dawn and the epoch of reionization. The global spectrum can potentially be detected with a single antenna and spectrometer. However, this measurement requires an extremely…

Instrumentation and Methods for Astrophysics · Physics 2024-12-10 Shijie Sun , Eloy de Lera Acedo , Fengquan Wu , Bin Yue , Jiacong Zhu , Xuelei Chen

A proposed method for dealing with foreground emission in upcoming 21-cm observations from the epoch of reionization is to limit observations to an uncontaminated window in Fourier space. Foreground emission can be avoided in this way,…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-23 Hannes Jensen , Suman Majumdar , Garrelt Mellema , Adam Lidz , Ilian T. Iliev , Keri L. Dixon

Observations of the 21-cm line from primordial hydrogen promise to be one of the best tools to study the early epochs of the Universe: the Dark Ages, the Cosmic Dawn, and the subsequent Epoch of Reionization. In 2018, the EDGES experiment…

Calibration precision is currently a limiting systematic in 21 cm cosmology experiments. While there are innumerable calibration approaches, most can be categorized as either `sky-based,' relying on an extremely accurate model of…

Instrumentation and Methods for Astrophysics · Physics 2021-03-17 Ruby Byrne , Miguel F. Morales , Bryna Hazelton , Michael Wilensky

The radio observation of 21\,cm-line signal from the Epoch of Reionization (EoR) enables us to explore the evolution of galaxies and intergalactic medium in the early universe. However, the detection and imaging of the 21\,cm-line signal…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-30 Shintaro Yoshiura , Hayato Shimabukuro , Kenji Hasegawa , Keitaro Takahashi

21 cm Epoch of Reionization observations promise to transform our understanding of galaxy formation, but these observations are impossible without unprecedented levels of instrument calibration. We present end-to-end simulations of a full…

Instrumentation and Methods for Astrophysics · Physics 2016-06-09 N. Barry , B. Hazelton , I. Sullivan , M. F. Morales , J. C. Pober

Accurate detection of the cosmological 21-cm global signal requires galactic foreground models which can remove power over ~$10^6$. Although foreground and global signal models unavoidably exhibit overlap in their vector-spaces inducing…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-31 Joshua J. Hibbard , David Rapetti , Jack O. Burns , Nivedita Mahesh , Neil Bassett

We propose a continuous wavelet transform based non-parametric foreground subtraction method for the detection of redshifted 21 cm signal from the epoch of reionization. This method works based on the assumption that the foreground spectra…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Junhua Gu , Haiguang Xu , Jingying Wang , Tao An , Wen Chen

Power spectrum of \HI 21-cm radiation is one of the promising probes to study large scale structure of the universe and understand galaxy formation and evolution. The presence of foregrounds, that are orders of magnitude larger in the same…

Instrumentation and Methods for Astrophysics · Physics 2025-05-28 Saikat Gayen , Rashmi Sagar , Sarvesh Mangla , Prasun Dutta , Nirupam Roy , Arnab Chakraborty , Jais Kumar , Abhirup Datta , Samir Choudhuri

Detection of the global redshifted 21-cm signal is an excellent means of deciphering the physical processes during the Dark Ages and subsequent Epoch of Reionization (EoR). However, detection of this faint monopole is challenging due to…

Instrumentation and Methods for Astrophysics · Physics 2015-12-16 Saurabh Singh , Ravi Subrahmanyan , N. Udaya Shankar , A. Raghunathan

Multiple instruments are pursuing constraints on dark energy, observing reionization and opening a window on the dark ages through the detection and characterization of the 21cm hydrogen line across the redshift spectrum, from nearby to…

Instrumentation and Methods for Astrophysics · Physics 2016-10-11 Daniel C. Jacobs , Jacob Burba , Judd Bowman , Abraham R. Neben , Benjamin Stinnett , Lauren Turner

Upcoming 21-cm intensity surveys will use the hyperfine transition in emission to map out neutral hydrogen in large volumes of the universe. Unfortunately, large spatial scales are completely contaminated with spectrally smooth…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-27 Chirag Modi , Martin White , Anze Slosar , Emanuele Castorina

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 present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-16 Steven G. Murray , Cathryn M. Trott , Christopher H. Jordan