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We report a novel radio autocorrelation (AC) search for extraterrestrial intelligence (SETI). For selected frequencies across the terrestrial microwave window (1-10 GHz) observations were conducted at the Allen Telescope Array to identify…

Precision measurements are reported of the cross-spectrum of rotationally-induced differential position displacements in a pair of colocated 39 m long, high power Michelson interferometers. One arm of each interferometer is bent…

Long-period radio transients (LPTs) are a recently identified phenomenon that challenge our current understanding of compact objects and coherent radio emission mechanisms. These objects emit radio pulses similar to those of pulsars, but at…

Free electrons in the interstellar medium cause frequency-dependent delays in pulse arrival times due to both scattering and dispersion. Multi-frequency measurements are used to estimate and remove dispersion delays. In this paper, we focus…

High Energy Astrophysical Phenomena · Physics 2015-06-23 M. T. Lam , J. M. Cordes , S. Chatterjee , T. Dolch

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

We measured signals of low amplitudes originating from cosmic rays, using two rectangular-block scintillation detectors at various positions. The signals were analyzed by a slightly modified signal analyzer from project 'MuonLab', designed…

Instrumentation and Detectors · Physics 2022-11-10 Jan Oldenziel

Interstellar signals might be intermittent for many reasons, such as targeted sequential transmissions, or isotropic broadcasts that are not on continuously, or many other reasons. The time interval between such signals would be important,…

Instrumentation and Methods for Astrophysics · Physics 2021-10-26 Robert H. Gray

Radio waves propagating from distant pulsars in the interstellar medium (ISM), are refracted by electron density inhomogeneities, so that the intensity of observed pulses fluctuates with time. The theory relating the observed pulse…

Astrophysics · Physics 2009-11-10 Stanislav Boldyrev , Carl R. Gwinn

A number of radio interferometers are currently being planned or constructed to observe 21 cm emission from reionization. Not only will such measurements provide a detailed view of that epoch, but, since the 21 cm emission also traces the…

The frequency dependence of radio pulse arrival times provides a probe of structures in the intervening media. Demorest et al. 2013 was the first to show a short-term (~100-200 days) reduction in the electron content along the line of sight…

The dynamic spectrum of a radio pulsar is an in-line digital hologram of the ionised interstellar medium. It has previously been demonstrated that such holograms permit image reconstruction, in the sense that one can determine an…

Astrophysics · Physics 2009-11-13 Mark Walker , Leon Koopmans , Dan Stinebring , Willem van Straten

We present a theoretical background for the data analysis of the gravitational-wave signals from spinning neutron stars for Earth-based laser interferometric detectors. We introduce a detailed model of the signal including both the…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Piotr Jaranowski , Andrzej Królak , Bernard F. Schutz

The long-standing assumption of symmetric radio emission beams from the two magnetic poles of pulsars is challenged by observational evidence of asymmetry and underfill. Direct testing of this symmetry remains difficult for most pulsars. As…

High Energy Astrophysical Phenomena · Physics 2026-05-01 Xiancong Wu , Hongguang Wang , Hao Tong , Rui Luo , Pengfei Wang , Chengbing Lyu , Hai Lei

The precise measurement of the sky-averaged HI absorption signal between 50 and 200 MHz is the primary goal of global 21-cm cosmology. This measurement has the potential to unravel the underlying physics of cosmic structure formation and…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-04 Emma Shen , Dominic Anstey , Marta Spinelli , Eloy de Lera Acedo , Anastasia Fialkov

Global (i.e. sky-averaged) $21$~cm signal experiments can measure the evolution of the universe from the Cosmic Dawn to the Epoch of Reionization. These measurements are challenged by the presence of bright foreground emission that can be…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 Marta Spinelli , Gianni Bernardi , Mario G. Santos

The Parkes telescope has been monitoring 286 radio pulsars approximately monthly since 2007 at an observing frequency of 1.4 GHz. The wide dispersion measure (DM) range of the pulsar sample and the uniformity of the observing procedure make…

High Energy Astrophysical Phenomena · Physics 2021-01-06 H. Kumamoto , S. Dai , S. Johnston , M. Kerr , R. M. Shannon , P. Weltevrede , C. Sobey , R. N. Manchester , G. Hobbs , K. Takahashi

Recent optical astrometric and spectroscopic surveys have identified numerous neutron star (NS) candidates in non-accreting detached binary systems, but their compact-object nature remains unconfirmed. In this work, we present targeted…

High Energy Astrophysical Phenomena · Physics 2025-11-26 Shi-Jie Gao , Xiang-Dong Li , Song Wang , Kareem El-Badry , De-Jiang Zhou , Yi-Xuan Shao , Zhen Yan , Pei Wang , Ping Zhou , Jin-Lin Han

We present the first radio observations of a sample of 13 optically and IR bright southern hemisphere classical Be stars made from the Australian Telescope Compact Array at 3.5cm and 6.3cm simultaneously. One star, delta Cen was detected at…

Astrophysics · Physics 2009-10-30 J S Clark , I A Steele , R P Fender

We report on a full-polarization analysis of the first 25 as yet non-repeating FRBs detected at 1.4 GHz by the 110-antenna Deep Synoptic Array (DSA-110) during commissioning observations. We present details of the data-reduction,…