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Understanding diffuse Galactic radio emission is interesting both in its own right and for minimizing foreground contamination of cosmological measurements. Cosmic Microwave Background experiments have focused on frequencies > 10 GHz,…

We study the impact of sky-based calibration errors from source mismodeling on 21\,cm power spectrum measurements with an interferometer and propose a method for suppressing their effects. While emission from faint sources that are not…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Aaron Ewall-Wice , Joshua S. Dillon , Adrian Liu , Jacqueline Hewitt

Distributed calibration based on consensus optimization is a computationally efficient method to calibrate large radio interferometers such as LOFAR and SKA. Calibrating along multiple directions in the sky and removing the bright…

Instrumentation and Methods for Astrophysics · Physics 2021-10-29 Sarod Yatawatta

We present a new approach to multi-frequency synthesis in radio astronomy. Using Bayesian inference techniques, the new technique estimates the sky brightness and the spectral index simultaneously. In principle, the bandwidth of a wide-band…

Instrumentation and Methods for Astrophysics · Physics 2015-09-16 H. Junklewitz , M. A. Bell , T. Enßlin

A new generation of interferometric instruments is emerging which aim to use intensity mapping of redshifted $21\,$cm radiation to measure the large-scale structure of the Universe at $z\simeq 1-2$ over wide areas of sky. While these…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-16 Martin White , Nikhil Padmanabhan

We present design equations for a two-element closely-spaced interferometer for measuring the noise temperature of a uniform sky. Such an interferometer is useful for observing highly diffuse radio sources such as the Milky Way and…

Instrumentation and Methods for Astrophysics · Physics 2020-09-11 Adrian T. Sutinjo , Benjamin McKinley , Leonid Belostotski , Daniel C. X. Ung , Jishnu N. Thekkeppattu

Data from radio interferometers provide a substantial challenge for statisticians. It is incomplete, noise-dominated and originates from a non-trivial measurement process. The signal is not only corrupted by imperfect measurement devices…

Instrumentation and Methods for Astrophysics · Physics 2020-11-11 Philipp Arras , Jakob Knollmüller , Henrik Junklewitz , Torsten A. Enßlin

The radio sky at lower frequencies, particularly below 20 MHz, is expected to be a combination of increasingly bright non-thermal emission and significant absorption from intervening thermal plasma. The sky maps at these frequencies cannot…

Instrumentation and Methods for Astrophysics · Physics 2021-09-01 Akhil Jaini , Avinash A. Deshpande , Sainath Bitragunta

This paper indicates that the sensitivity and accuracy of an infrared radiometer for emissivity measurements depends not only on its design and the measurement method, but also on the spurious radiation. This spurious radiation must be…

We present a visibility based estimator namely, the Tapered Gridded Estimator (TGE) to estimate the power spectrum of the diffuse sky signal. The TGE has three novel features. First, the estimator uses gridded visibilities to estimate the…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-16 Samir Choudhuri

The advent of a new generation of low frequency interferometers has opened a direct window into the Epoch of Reionisation (EoR). However, key to a detection of the faint 21-cm signal, and reaching the sensitivity limits of these arrays, is…

Instrumentation and Methods for Astrophysics · Physics 2018-12-05 Ronniy C. Joseph , Cathryn M. Trott , Randall B. Wayth

We report absolutely calibrated measurements of diffuse radio emission between 90 and 190 MHz from the Experiment to Detect the Global EoR Signature (EDGES). EDGES employs a wide beam zenith-pointing dipole antenna centred on a declination…

Instrumentation and Methods for Astrophysics · Physics 2016-10-25 Thomas. J. Mozdzen , Judd. D. Bowman , Raul. A. Monsalve , Alan. E. E. Rogers

The sky-averaged, or global, background of redshifted $21$ cm radiation is expected to be a rich source of information on cosmological reheating and reionizaton. However, measuring the signal is technically challenging: one must extract a…

Instrumentation and Methods for Astrophysics · Physics 2016-08-03 Tejaswi Venumadhav , Tzu-Ching Chang , Olivier Doré , Christopher M. Hirata

The INTEGRAL observatory has been performing a deep survey of the Galactic central radian since 2003, with the goal of both extracting a catalog of sources and gaining insight into the Galactic diffuse emission. This paper concentrates on…

Astrophysics · Physics 2016-08-30 L. Bouchet , J. P. Roques , P. Mandrou , A. Strong , R. Diehl , F. Lebrun , R. Terrier

Radio Frequency Interference (RFI) presents a significant challenge for carrying out precision measurements in radio astronomy. In particular, RFI can be a showstopper when looking for faint cosmological signals such as the red-shifted…

We present an improved Global Sky Model (GSM) of diffuse galactic radio emission from 10 MHz to 5 THz, whose uses include foreground modeling for CMB and 21 cm cosmology. Our model improves on past work both algorithmically and by adding…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-05 Haoxuan Zheng , Max Tegmark , Joshua S. Dillon , Doyeon A. Kim , Adrian Liu , Abraham Neben , Justin Jonas , Patricia Reich , Wolfgang Reich

In observations of diffuse emissions like, e.g., the Lyman-$\alpha$ heliospheric glow, contributions to the observed signal from point sources (e.g., stars) are considered as a contamination. There are relatively few brightest point sources…

Solar and Stellar Astrophysics · Physics 2020-08-19 Marek Strumik , Maciej Bzowski , Izabela Kowalska-Leszczynska , Marzena A. Kubiak

The Radio Interferometer Measurement Equation (RIME) is a matrix-based mathematical model that describes the response of a radio interferometer. The Jones calculus it employs is not suitable for describing the analogue components of a…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Danny C. Price , Oleg M. Smirnov

We have mapped the total sky brightness at 1465 MHz in two adjacent 60-degree declination bands with the portable 5.5-m parabolic reflector of the Galactic Emission Mapping (GEM) project, an on-going international collaboration to survey…

Astrophysics · Physics 2007-05-23 C. Tello , T. Villela , G. F. Smoot , S. Torres , M. Bersanelli

Upcoming radio surveys will probe the sky with unprecedented depth and sky coverage, enabling a broad range of cosmological and astrophysical applications, as well as powerful synergies with experiments at other wavelengths. The preparation…