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Radio-detection is a mature technique that has gained large momentum over the past decades. Its physical detection principle is mainly driven by the electromagnetic part of the shower, and is therefore not too sensitive to uncertainties on…
We present the spectrum of cosmic rays with energies above 2.5 EeV measured at the Pierre Auger Observatory after 19 years of operation, covering the period before the AugerPrime upgrade. Two independent event sets from the surface array of…
Radio detection of cosmic-ray air showers requires time synchronization of detectors on a nanosecond level, especially for advanced reconstruction algorithms based on the wavefront curvature and for interferometric analysis approaches. At…
As part of the ongoing AugerPrime upgrade of the Pierre Auger Observatory, we are deploying short aperiodic loaded loop antennas measuring radio signals from extensive air showers in the 30-80 MHz band on each of the 1,660 surface detector…
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…
The Askaryan Radio Array (ARA) is an in-ice ultrahigh energy (UHE) neutrino experiment at the South Pole. ARA aims to detect the radio emissions from neutrino-induced particle showers using in-ice clusters of antennas buried ${\sim}200$ m…
The Pierre Auger Observatory has been designed to study the highest-energy cosmic rays in nature (E > 10^{18.5} eV). The determination of their arrival direction, energy and composition is performed by the analysis of the atmospheric…
The Askaryan Radio Array (ARA) is an ultra-high energy (UHE) neutrino telescope at the South Pole consisting of an array of radio antennas aimed at detecting the Askaryan radiation produced by neutrino interactions in the ice. Currently,…
Detection of the mostly geomagnetically generated radio emission of cosmic-ray air showers provides an alternative to air-Cherenkov and air-fluorescence detection, since it is not limited to clear nights. Like these established methods, the…
The development of sensitive large format imaging arrays for the infrared promises to provide revolutionary capabilities for space astronomy. For example, the Infrared Array Camera (IRAC) on SIRTF will use four 256 x 256 arrays to provide…
As of early 2025, the GRAND Collaboration operates three prototype arrays: GRANDProto300 in China, GRAND@Nan\c{c}ay in France, and GRAND@Auger in Argentina. The GRAND@Auger prototype was established through an agreement between the GRAND…
We present the GIGAS (Gigahertz Identification of Giant Air Shower) microwave radio sensor arrays of the EASIER project (Extensive Air Shower Identification with Electron Radiometers), deployed at the site of the Pierre Auger cosmic ray…
The arrival directions of cosmic rays detected by the Pierre Auger Observatory (Auger) with energies above 39~EeV were recently reported to correlate with the positions of 23 nearby starburst galaxies (SBGs): in their best-fit model, 9.7\%…
The CHARA Array is the longest baseline optical interferometer in the world. Operated with natural seeing, it has delivered landmark sub-milliarcsecond results in the areas of stellar imaging, binaries, and stellar diameters. However, to…
The Tunka Radio Extension (Tunka-Rex) is an array of 44 radio antenna stations, distributed over 3 km$^{2}$, constituting a radio detector for air showers with an energy threshold around 10$^{17}$ eV. It is an extension to Tunka-133, an…
The Infrared Array Camera (IRAC) on the Spitzer Space Telescope is absolutely calibrated by comparing photometry on a set of A stars near the north ecliptic pole to predictions based on ground-based observations and a stellar atmosphere…
At present there are still several open questions about the origin of the ultra high energy cosmic rays. However, great progress in this area has been made in recent years due to the data collected by the present generation of ground based…
We have used the Very Large Array (VLA) to conduct a survey for radio continuum emission in the sample of 52 Seyfert nuclei selected from the optical spectroscopic galaxy catalog of Ho, Filippenko, and Sargent. This Seyfert sample is the…
Binary and dual active galactic nuclei (AGN) are an important observational tool for studying the formation and dynamical evolution of galaxies and supermassive black holes (SMBHs). An entirely new method for identifying possible AGN pairs…
This paper presents the highlights from the recent measurements of the energy spectrum, mass composition, and arrival directions of the ultra-high energy ($> 10^{17}$ eV = 0.1 EeV) cosmic rays (UHECR) by the Pierre Auger Observatory. The…