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The upper $100 \, \mathrm{m}$ to $150 \, \mathrm{m}$ of the polar ice sheet, called the firn, has a time-dependent density due to seasonal variations in the surface temperature and snow accumulation. We present RF simulations of an in-ice…

High Energy Astrophysical Phenomena · Physics 2026-02-18 Alexander Kyriacou , Steven Prohira , Dave Besson

The rapid development of new generation radio interferometers such as the Square Kilometer Array (SKA) has opened up unprecedented opportunities for astronomical research. However, anthropogenic Radio Frequency Interference (RFI) from…

Instrumentation and Methods for Astrophysics · Physics 2022-03-02 Haomin Sun , Hui Deng , Feng Wang , Ying Mei , Tingting Xu , Oleg Smirnov , Linhua Deng , Shoulin Wei

After reionization, emission in the 21 cm hyperfine transition provides a direct probe of neutral hydrogen distributed in galaxies. Different from galaxy redshift surveys, observation of baryon acoustic oscillations in the cumulative 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-14 Xiao-Chun Mao

We have constructed and operated the Survey for Transient Astronomical Radio Emission (STARE) to detect transient astronomical radio emission at 611 MHz originating from the sky over the northeastern United States. The system is sensitive…

Astrophysics · Physics 2009-11-07 C. A. Katz , J. N. Hewitt , B. E. Corey , C. B. Moore

The radio properties of 11 obscured `radio-intermediate' quasars at redshifts z>~2 have been investigated using the European Very-Long-Baseline-Interferometry Network (EVN) at 1.66 GHz. A sensitivity of ~25 micro Jy per 14x17 mas2 beam was…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 H. -R. Kloeckner , A. Martinez-Sansigre , S. Rawlings , M. A. Garrett

Radio Frequency Interference (RFI) from anthropogenic radio sources poses significant challenges to current and future radio telescopes. Contemporary approaches to detecting RFI treat the task as a semantic segmentation problem on radio…

Neural and Evolutionary Computing · Computer Science 2026-01-23 Nicholas J Pritchard , Andreas Wicenec , Mohammed Bennamoun , Richard Dodson

Observations of fluctuations in the redshifted 21 cm radiation from neautral hydrogen (HI) are perceived to be an important future probe of the universe at high redshifts. Under the assumption that at redshifts z less than 6…

Astrophysics · Physics 2009-11-13 Sk. Saiyad Ali , Somnath Bharadwaj , Sanjay K. Pandey

The Medium-Resolution Spectrometer (MRS) provides one of the four operating modes of the Mid-Infrared Instrument (MIRI) on board the James Webb Space Telescope (JWST). The MRS is an integral field spectrometer, measuring the spatial and…

We present a sample of 1317 Infrared-Faint Radio Sources (IFRSs) that, for the first time, are reliably detected in the infrared, generated by cross-correlating the Wide-Field Infrared Survey Explorer (WISE) all-sky survey with major radio…

The "ALFA Ultra Deep Survey" (AUDS) is an ongoing 21-cm spectral survey with the Arecibo 305m telescope. AUDS will be the most sensitive blind survey undertaken with Arecibo's 300 MHz Mock spectrometer. The survey searches for 21-cm HI line…

Radio frequency interference (RFI) and malicious jammers are a significant problem in our wireless world. Detecting RFI or jamming is typically performed with model-based statistical detection or AI-empowered algorithms that use an input…

Signal Processing · Electrical Eng. & Systems 2025-07-29 Christos Ntemkas , Antonios Argyriou

The Murchison Widefield Array (MWA) team has derived new upper limits on the spherically averaged power spectrum of the 21-cm signal at six redshifts in the range $z \approx 6.5-8.7$. We use these upper limits and a Bayesian inference…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-24 Raghunath Ghara , Sambit K. Giri , Benedetta Ciardi , Garrelt Mellema , Saleem Zaroubi

The redshifted 21 cm brightness distribution from neutral hydrogen is a promising probe into the cosmic dark ages, cosmic dawn, and re-ionization. LOFAR's Low Band Antennas (LBA) may be used in the frequency range 45 MHz to 85 MHz (30>z>16)…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 H. K. Vedantham , L. V. E. Koopmans , A. G. de Bruyn , S. J. Wijnholds , B. Ciardi , M. A. Brentjens

A real-time broadband RFI mitigation system has been developed for the Upgraded GMRT (uGMRT). Here, we report the engineering, imaging, and beam/pulsar results from the test observations in all the bands of the uGMRT during the monsoon of…

Instrumentation and Methods for Astrophysics · Physics 2025-06-23 Ruta Kale , Kaushal D. Buch , Sanjay Kudale , Mekhala Muley , Ajith Kumar B.

We present millimeter and radio observations of 13 SDSS quasars at reshifts z~6. We observed eleven of them with the Max-Planck Millimeter Bolometer Array (MAMBO-2) at the IRAM 30m-telescope at 250 GHz and all of them with the Very Large…

Radio Frequency Interference (RFI), the presence of artificial and/or terrestrial signals in astronomical data, poses a great challenge to the search for pulsars and radio transients, such as Rotating Radio Transients (RRATs) and Fast Radio…

Instrumentation and Methods for Astrophysics · Physics 2026-01-15 R. S. Hombal , L. Levin , B. W. Stappers , M. Droog , A. Karastergiou , D. Lumbaa , M. B. Mickaliger , A. Naidu , K. M. Rajwade , J. Sepulveda , B. Shaw , S. Singh , T. Prabu

We measure the radio luminosity function (RLF) of steep-spectrum radio sources using three redshift surveys of flux-limited samples selected at low (151 & 178 MHz) radio frequency, low-frequency source counts and the local RLF. The redshift…

Radio interferometric observations are less susceptible to radio frequency interference (RFI) than single dish observations. This is primarily due to : (1)fringe-frequency averaging at the correlator output and (2) bandwidth decorrelation…

Astrophysics · Physics 2007-05-23 D. Anish Roshi , R. A. Perley

We have used the Fisher matrix formalism to quantify the prospects of detecting the z = 3.35 redshifted 21-cm HI power spectrum with the upcoming radio-imterferometric array OWFA. OWFA's frequency and baseline coverage spans comoving…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-28 Somnath Bharadwaj , Anjan Kumar Sarkar , Sk. Saiyad Ali