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21cm tomography promises to be a powerful tool for estimating cosmological parameters, constraining the epoch of reionization, and probing the so-called dark ages. However, realizing this promise will require the extraction of a…

宇宙学与河外天体物理 · 物理学 2011-06-02 Adrian Liu , Max Tegmark

Angular power spectra and structure functions of the Stokes parameters Q and U and polarized intensity P are derived from three sets of radio polarimetric observations. Two of the observed fields have been studied at multiple frequencies,…

天体物理学 · 物理学 2011-05-23 M. Haverkorn , P. Katgert , A. G. de Bruyn

We quantify the effect of radio frequency interference (RFI) on measurements of the 21-cm power spectrum during the Epoch of Reionization (EoR). Specifically, we investigate how the frequency structure of RFI source emission generates…

天体物理仪器与方法 · 物理学 2020-09-09 Michael J. Wilensky , Nichole Barry , Miguel F. Morales , Bryna J. Hazelton , Ruby Byrne

We present the first of two papers dedicated to verifying the Australian Epoch of Reionisation pipeline (AusEoRPipe) through simulation. The AusEoRPipe aims to disentangle 21-cm radiation emitted by gas surrounding the very first stars from…

天体物理仪器与方法 · 物理学 2024-04-09 J. L. B. Line , C. M. Trott , J. H. Cook , B. Greig , N. Barry , C. H. Jordan

We present the first deep polarimetric study of Galactic synchrotron emission at low radio frequencies. Our study is based on 21 observations of the European Large Area Infrared Space Observatory Survey-North 1 (ELAIS-N1) field using the…

The redshifted cosmological 21 cm signal emitted by neutral hydrogen during the first billion years of the universe is much fainter relative to other galactic and extragalactic radio emissions, posing a great challenge towards detection of…

宇宙学与河外天体物理 · 物理学 2022-07-26 J. Kariuki Chege , C. H. Jordan , C. Lynch , C. M. Trott , J. L. B. Line , B. Pindor , S. Yoshiura

Interfacial polarization-charge accumulation at the heterointerface-is a well-established tool in semiconductors, but its influence in metals remains unexplored. Here, we demonstrate that interfacial polarization can robustly modulate…

Leakage of polarized Galactic diffuse emission into total intensity can potentially mimic the 21-cm signal coming from the epoch of reionization (EoR), as both of them might have fluctuating spectral structure. Although we are sensitive to…

天体物理仪器与方法 · 物理学 2018-02-28 K. M. B. Asad , L. V. E. Koopmans , V. Jelić , A. G. de Bruyn , V. N. Pandey , B. K. Gehlot

The removal of the Galactic and extragalactic foregrounds remains a major challenge for those wishing to make a detection of the Epoch of Reionization 21-cm signal. Multiple methods of modelling these foregrounds with varying levels of…

宇宙学与河外天体物理 · 物理学 2016-09-13 Emma Chapman , Saleem Zaroubi , Filipe Abdalla , Fred Dulwich , Vibor Jelić , Benjamin Mort

Cross-correlating 21cm and Ly$\alpha$ intensity maps of the Epoch of Reionization (EoR) promises to be a powerful tool for exploring the properties of the first galaxies. Next-generation intensity mapping experiments such as the Hydrogen…

宇宙学与河外天体物理 · 物理学 2022-03-02 Tyler A. Cox , Daniel C. Jacobs , Steven G. Murray

A critical challenge in measuring the power spectrum of 21cm emission from cosmic reionization is compensating for the frequency dependence of an interferometer's sampling pattern, which can cause smooth-spectrum foregrounds to appear…

天体物理仪器与方法 · 物理学 2015-06-04 Aaron R. Parsons , Jonathan C. Pober , James E. Aguirre , Christopher L. Carilli , Daniel C. Jacobs , David F. Moore

A number of experiments are set to measure the 21-cm signal of neutral hydrogen from the Epoch of Reionization (EoR). The common denominator of these experiments are the large data sets produced, contaminated by various instrumental…

The upcoming Square Kilometre Array Low Frequency (SKA-Low) interferometer will have the required sensitivity to detect the 21 cm line from neutral hydrogen during the Epoch of Reionisation (EoR). In preparation, we investigated the…

天体物理仪器与方法 · 物理学 2025-09-25 E. Jong , C. Trott , C. D. Nunhokee , Q. Zheng

Polarization induced by cosmological scalar perturbations leads to a typical anisotropy pattern, which can best be analyzed in Fourier domain. This allows one to unambiguously distinguish cosmological signal of polarization from other…

天体物理学 · 物理学 2009-10-28 Uros Seljak

Precise subtraction of foreground sources is crucial for detecting and estimating 21cm HI signals from the Epoch of Reionization (EoR). We quantify how imperfect point source subtraction due to limitations of the measurement dataset yields…

宇宙学与河外天体物理 · 物理学 2015-06-11 Cathryn M. Trott , Randall B. Wayth , Steven J. Tingay

Over the next year, a new era of observations of compact objects in X-ray polarization will commence. Among the key targets for the upcoming Imaging X-ray Polarimetry Explorer mission, will be the magnetars 4U 0142+61 and 1RXS…

高能天体物理现象 · 物理学 2022-06-22 Ilaria Caiazzo , Denis González-Caniulef , Jeremy Heyl , Rodrigo Fernández

We test the hypothesis that limitations in the sky model used to calibrate an interferometric radio telescope, where the model contains extended radio sources, will generate bias in the Epoch of Reionisation (EoR) power spectrum. The…

天体物理仪器与方法 · 物理学 2017-11-29 Cathryn M. Trott , Randall B. Wayth

Detecting redshifted 21cm emission from neutral hydrogen in the early Universe promises to give direct constraints on the epoch of reionization (EoR). It will, though, be very challenging to extract the cosmological signal (CS) from…

Measurement of the global 21-cm signal during Cosmic Dawn (CD) and the Epoch of Reionization (EoR) is made difficult by bright foreground emission which is 2-5 orders of magnitude larger than the expected signal. Fitting for a…

宇宙学与河外天体物理 · 物理学 2024-02-20 Michael Pagano , Peter Sims , Adrian Liu , Dominic Anstey , Will Handley , Eloy De Lera Acedo

We investigate a region of the quiet solar photosphere exhibiting three-lobed Stokes V profiles in the Fe I spectral line at 15648 Angstroem. The data were acquired with the GRIS spectropolarimeter attached to the GREGOR telescope. We aim…

太阳与恒星天体物理 · 物理学 2018-08-29 Christoph Kiess , Juan Manuel Borrero , Wolfgang Schmidt