arXiv subjects

Alex Hegedus

Publications and source records attributed to Alex Hegedus.

5 recordsLinked to original sources

arXiv2026

The FarView Low Frequency Radio Array on the Moon's Far Side: Science and Array Architecture

FarView is a proposed low frequency radio interferometer for deployment on the lunar far side, enabled by the Moon's radio quiet environment. Operating over 1-50 MHz inaccessible from Earth, FarView will open a new observational window and promote discovery class science in cosmology, heliophysics, Galactic and exoplanet astrophysics. The primary science is measurement of the redshifted 21 cm signal from the Cosmic Dark Ages (z=30-100), identified by the Astro2020 Decadal Survey as a priority cosmology discovery area. FarView will deliver 3D tomographic measurements and precision power spectra of neutral hydrogen in a largely linear regime, enabling tests of inflationary initial conditions, primordial non Gaussianity, dark matter properties, neutrino masses, and early dark energy. The reference design consists of 100000 crossed dipole antennas in a dense core-halo configuration spanning 200 sq km. A compact 4 km core with 83000 dipoles maximizes sensitivity to large scale cosmological modes, while 20000 halo elements extending to 14 km provide angular resolution and calibration for foreground characterization. Sensitivity forecasts indicate a 10-sigma detection of the Dark Ages 21 cm power spectrum at z=30 over five years of half duty cycle lunar night observations. An FFT-based EPIC beamformer is identified as an efficient signal processing architecture. Beyond cosmology, FarView will enable interferometric imaging of low frequency solar radio bursts, advancing space weather studies. Additional capabilities include stellar space weather observations, Galactic cosmic ray tomography via free-free absorption, and searches for auroral radio emission from exoplanet magnetospheres, a probe of exoplanet habitability. FarView represents a flagship class opportunity to establish the Moon as a platform for foundational astrophysics while delivering unique observational capabilities.

astro-ph.IM↗

arXiv2024

FarView: An In-Situ Manufactured Lunar Far Side Radio Array Concept for 21-cm Dark Ages Cosmology

FarView is an early-stage concept for a large, low-frequency radio observatory, manufactured in-situ on the lunar far side using metals extracted from the lunar regolith. It consists of 100,000 dipole antennas in compact subarrays distributed over a large area but with empty space between subarrays in a core-halo structure. FarView covers a total area of ~200 km2, has a dense core within the inner ~36 km2, and a ~power-law falloff of antenna density out to ~14 km from the center. With this design, it is relatively easy to identify multiple viable build sites on the lunar far side. The science case for FarView emphasizes the unique capabilities to probe the unexplored Cosmic Dark Ages - identified by the 2020 Astrophysics Decadal Survey as the discovery area for cosmology. FarView will deliver power spectra and tomographic maps tracing the evolution of the Universe from before the birth of the first stars to the beginning of Cosmic Dawn, and potentially provide unique insights into dark matter, early dark energy, neutrino masses, and the physics of inflation. What makes FarView feasible and affordable in the timeframe of the 2030s is that it is manufactured in-situ, utilizing space industrial technologies. This in-situ manufacturing architecture utilizes Earth-built equipment that is transported to the lunar surface to extract metals from the regolith and will use those metals to manufacture most of the array components: dipole antennas, power lines, and silicon solar cell power systems. This approach also enables a long functional lifetime, by permitting servicing and repair of the observatory. The full 100,000 dipole FarView observatory will take 4 - 8 years to build, depending on the realized performance of the manufacturing elements and the lunar delivery scenario.

astro-ph.IM↗

arXiv2022

How to Deploy a 10-km Interferometric Radio Telescope on the Moon with Just Four Tethered Robots

The Far-side Array for Radio Science Investigations of the Dark ages and Exoplanets (FARSIDE) is a proposed mission concept to the lunar far side that seeks to deploy and operate an array of 128 dual-polarization, dipole antennas over a region of 100 square kilometers. The resulting interferometric radio telescope would provide unprecedented radio images of distant star systems, allowing for the investigation of faint radio signatures of coronal mass ejections and energetic particle events and could also lead to the detection of magnetospheres around exoplanets within their parent star's habitable zone. Simultaneously, FARSIDE would also measure the "Dark Ages" of the early Universe at a global 21-cm signal across a range of red shifts (z approximately 50-100). Each discrete antenna node in the array is connected to a central hub (located at the lander) via a communication and power tether. Nodes are driven by cold=operable electronics that continuously monitor an extremely wide-band of frequencies (200 kHz to 40 MHz), which surpass the capabilities of Earth-based telescopes by two orders of magnitude. Achieving this ground-breaking capability requires a robust deployment strategy on the lunar surface, which is feasible with existing, high TRL technologies (demonstrated or under active development) and is capable of delivery to the surface on next-generation commercial landers, such as Blue Origin's Blue Moon Lander. This paper presents an antenna packaging, placement, and surface deployment trade study that leverages recent advances in tethered mobile robots under development at NASA's Jet Propulsion Laboratory, which are used to deploy a flat, antenna-embedded, tape tether with optical communication and power transmission capabilities.

astro-ph.IM↗

arXiv2021

A Lunar Farside Low Radio Frequency Array for Dark Ages 21-cm Cosmology

An array of low-frequency dipole antennas on the lunar farside surface will probe a unique, unexplored epoch in the early Universe called the Dark Ages. It begins at Recombination when neutral hydrogen atoms formed, first revealed by the cosmic microwave background. This epoch is free of stars and astrophysics, so it is ideal to investigate high energy particle processes including dark matter, early Dark Energy, neutrinos, and cosmic strings. A NASA-funded study investigated the design of the instrument and the deployment strategy from a lander of 128 pairs of antenna dipoles across a 10 kmx10 km area on the lunar surface. The antenna nodes are tethered to the lander for central data processing, power, and data transmission to a relay satellite. The array, named FARSIDE, would provide the capability to image the entire sky in 1400 channels spanning frequencies from 100 kHz to 40 MHz, extending down two orders of magnitude below bands accessible to ground-based radio astronomy. The lunar farside can simultaneously provide isolation from terrestrial radio frequency interference, the Earth's auroral kilometric radiation, and plasma noise from the solar wind. It is thus the only location within the inner solar system from which sky noise limited observations can be carried out at sub-MHz frequencies. Through precision calibration via an orbiting beacon and exquisite foreground characterization, the farside array would measure the Dark Ages global 21-cm signal at redshifts z~35-200. It will also be a pathfinder for a larger 21-cm power spectrum instrument by carefully measuring the foreground with high dynamic range.

astro-ph.IM↗

arXiv2021

Low Radio Frequency Observations from the Moon Enabled by NASA Landed Payload Missions

A new era of exploration of the low radio frequency Universe from the Moon will soon be underway with landed payload missions facilitated by NASA's Commercial Lunar Payload Services (CLPS) program. CLPS landers are scheduled to deliver two radio science experiments, ROLSES to the nearside and LuSEE to the farside, beginning in 2021. These instruments would be pathfinders for a 10-km diameter interferometric array, FARSIDE, composed of 128 pairs of dipole antennas proposed to be delivered to the lunar surface later in the decade. ROLSES and LuSEE, operating at frequencies from 100 kHz to a few tens of MHz, will investigate the plasma environment above the lunar surface and measure the fidelity of radio spectra on the surface. Both use electrically-short, spiral-tube deployable antennas and radio spectrometers based upon previous flight models. ROLSES will measure the photoelectron sheath density to better understand the charging of the lunar surface via photoionization and impacts from the solar wind, charged dust, and current anthropogenic radio frequency interference. LuSEE will measure the local magnetic field and exo-ionospheric density, interplanetary radio bursts, Jovian and terrestrial natural radio emission, and the galactic synchrotron spectrum. FARSIDE, and its precursor risk-reduction six antenna-node array PRIME, would be the first radio interferometers on the Moon. FARSIDE would break new ground by imaging radio emission from Coronal Mass Ejections (CME) beyond 2 solar radii, monitor auroral radiation from the B-fields of Uranus and Neptune (not observed since Voyager), and detect radio emission from stellar CMEs and the magnetic fields of nearby potentially habitable exoplanets.

astro-ph.IM↗