David H. E. MacMahon
YOU?
Author Swipe
View article: Anomaly Detection and Radio-frequency Interference Classification with Unsupervised Learning in Narrowband Radio Technosignature Searches
Anomaly Detection and Radio-frequency Interference Classification with Unsupervised Learning in Narrowband Radio Technosignature Searches Open
The search for radio technosignatures is an anomaly detection problem: Candidate signals represent needles of interest in the proverbial haystack of radio-frequency interference (RFI). Current search frameworks find an enormity of false-po…
View article: <tt>matvis</tt>: a matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays
matvis: a matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays Open
Detection of the faint 21 cm line emission from the Cosmic Dawn and Epoch of Reionization will require not only exquisite control over instrumental calibration and systematics to achieve the necessary dynamic range of observations but also…
View article: Anomaly Detection and Radio-frequency Interference Classification with Unsupervised Learning in Narrowband Radio Technosignature Searches
Anomaly Detection and Radio-frequency Interference Classification with Unsupervised Learning in Narrowband Radio Technosignature Searches Open
The search for radio technosignatures is an anomaly detection problem: Candidate signals represent needles of interest in the proverbial haystack of radio-frequency interference (RFI). Current search frameworks find an enormity of false-po…
View article: A demonstration of the effect of fringe-rate filtering in the hydrogen epoch of reionization array delay power spectrum pipeline
A demonstration of the effect of fringe-rate filtering in the hydrogen epoch of reionization array delay power spectrum pipeline Open
Radio interferometers targeting the 21cm brightness temperature fluctuations at high redshift are subject to systematic effects that operate over a range of different time-scales. These can be isolated by designing appropriate Fourier filt…
View article: The First High Frequency Technosignature Search Survey with the Sardinia Radio Telescope
The First High Frequency Technosignature Search Survey with the Sardinia Radio Telescope Open
The quest for radio signals from technologically-advanced extraterrestrial intelligence has traditionally concentrated on the vicinity of 1.4 GHz. In this paper, we extend the search to unprecedented territories, detailing our extensive ob…
View article: Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data
Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data Open
Observations with radio arrays that target the 21-cm signal originating from the early Universe suffer from a variety of systematic effects. An important class of these are reflections and spurious couplings between antennas. We apply a Ha…
View article: Direct Optimal Mapping Image Power Spectrum and its Window Functions
Direct Optimal Mapping Image Power Spectrum and its Window Functions Open
The key to detecting neutral hydrogen during the epoch of reionization (EoR) is to separate the cosmological signal from the dominating foreground radiation. We developed direct optimal mapping (DOM) to map interferometric visibilities; it…
View article: Investigating Mutual Coupling in the Hydrogen Epoch of Reionization Array and Mitigating its Effects on the 21-cm Power Spectrum
Investigating Mutual Coupling in the Hydrogen Epoch of Reionization Array and Mitigating its Effects on the 21-cm Power Spectrum Open
Interferometric experiments designed to detect the highly redshifted 21-cm signal from neutral hydrogen are producing increasingly stringent constraints on the 21-cm power spectrum, but some k-modes remain systematics-dominated. Mutual cou…
View article: Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning
Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning Open
This paper presents the design and deployment of the Hydrogen Epoch of Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements of the Epoch of Reionization. First results fro…
View article: A demonstration of the effect of fringe-rate filtering in the Hydrogen Epoch of Reionization Array delay power spectrum pipeline
A demonstration of the effect of fringe-rate filtering in the Hydrogen Epoch of Reionization Array delay power spectrum pipeline Open
Radio interferometers targeting the 21cm brightness temperature fluctuations at high redshift are subject to systematic effects that operate over a range of different timescales. These can be isolated by designing appropriate Fourier filte…
View article: A Radio Technosignature Search of Six Resonant Sub-Neptunes Orbiting HD 110067
A Radio Technosignature Search of Six Resonant Sub-Neptunes Orbiting HD 110067 Open
We describe archival observations and analysis of the HD 110067 planetary system using the Green Bank Telescope (GBT) as part of the Breakthrough Listen search for technosignatures. The star hosts six sub-Neptune planets in resonant orbits…
View article: Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning
Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning Open
This paper presents the design and deployment of the Hydrogen Epoch of Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements of the Epoch of Reionization. First results fro…
View article: COSMIC: An Ethernet-based Commensal, Multimode Digital Backend on the Karl G. Jansky Very Large Array for the Search for Extraterrestrial Intelligence
COSMIC: An Ethernet-based Commensal, Multimode Digital Backend on the Karl G. Jansky Very Large Array for the Search for Extraterrestrial Intelligence Open
The primary goal of the search for extraterrestrial intelligence is to gain an understanding of the prevalence of technologically advanced beings (organic or inorganic) in the Galaxy. One way to approach this is to look for technosignature…
View article: matvis: A matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays
matvis: A matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays Open
Detection of the faint 21 cm line emission from the Cosmic Dawn and Epoch of Reionisation will require not only exquisite control over instrumental calibration and systematics to achieve the necessary dynamic range of observations but also…
View article: The Breakthrough Listen Search for Intelligent Life: Technosignature Search of 97 Nearby Galaxies
The Breakthrough Listen Search for Intelligent Life: Technosignature Search of 97 Nearby Galaxies Open
The Breakthrough Listen search for intelligent life is, to date, the most extensive technosignature search of nearby celestial objects. We present a radio technosignature search of the centers of 97 nearby galaxies, observed by Breakthroug…
View article: Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data
Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data Open
Observations with radio arrays that target the 21-cm signal originating from the early Universe suffer from a variety of systematic effects. An important class of these are reflections and spurious couplings between antennas. We apply a Ha…
View article: Direct Optimal Mapping Image Power Spectrum and its Window Functions
Direct Optimal Mapping Image Power Spectrum and its Window Functions Open
The key to detecting neutral hydrogen during the epoch of reionization (EoR) is to separate the cosmological signal from the dominating foreground radiation. We developed direct optimal mapping (DOM) to map interferometric visibilities; it…
View article: A 4–8 GHz Galactic Center Search for Periodic Technosignatures
A 4–8 GHz Galactic Center Search for Periodic Technosignatures Open
Radio searches for extraterrestrial intelligence have mainly targeted the discovery of narrowband continuous-wave beacons and artificially dispersed broadband bursts. Periodic pulse trains, in comparison to the above technosignature morpho…
View article: An interferometric SETI observation of Kepler-111 b
An interferometric SETI observation of Kepler-111 b Open
The application of very long baseline interferometry (VLBI) to the search for extraterrestrial intelligence (SETI) has been limited to date, despite the technique offering many advantages over traditional single-dish SETI observations. In …
View article: Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations Open
We report the most sensitive upper limits to date on the 21 cm epoch of reionization power spectrum using 94 nights of observing with Phase I of the Hydrogen Epoch of Reionization Array (HERA). Using similar analysis techniques as in previ…
View article: Search for the Epoch of Reionization with HERA: upper limits on the closure phase delay power spectrum
Search for the Epoch of Reionization with HERA: upper limits on the closure phase delay power spectrum Open
Radio interferometers aiming to measure the power spectrum of the redshifted 21 cm line during the Epoch of Reionization (EoR) need to achieve an unprecedented dynamic range to separate the weak signal from overwhelming foreground emission…
View article: Characterization of inpaint residuals in interferometric measurements of the epoch of reionization
Characterization of inpaint residuals in interferometric measurements of the epoch of reionization Open
To mitigate the effects of Radio Frequency Interference (RFI) on the data analysis pipelines of 21 cm interferometric instruments, numerous inpaint techniques have been developed. In this paper, we examine the qualitative and quantitative …
View article: A Green Bank Telescope Search for Narrowband Technosignatures between 1.1 and 1.9 GHz During 12 Kepler Planetary Transits
A Green Bank Telescope Search for Narrowband Technosignatures between 1.1 and 1.9 GHz During 12 Kepler Planetary Transits Open
Agrowing avenue for determining the prevalence of life beyond Earth is to search for “technosignatures” from extraterrestrial intelligences/agents. Technosignatures require significant energy to be visible across interstellar space and thu…
View article: Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum
Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum Open
Combining the visibilities measured by an interferometer to form a cosmological power spectrum is a complicated process. In a delay-based analysis, the mapping between instrumental and cosmological space is not a one-to-one relation. Inste…
View article: A Green Bank Telescope search for narrowband technosignatures between 1.1-1.9 GHz during 12 Kepler planetary transits
A Green Bank Telescope search for narrowband technosignatures between 1.1-1.9 GHz during 12 Kepler planetary transits Open
A growing avenue for determining the prevalence of life beyond Earth is to search for "technosignatures" from extraterrestrial intelligences/agents. Technosignatures require significant energy to be visible across interstellar space and th…
View article: Bayesian jackknife tests with a small number of subsets: application to HERA 21 cm power spectrum upper limits
Bayesian jackknife tests with a small number of subsets: application to HERA 21 cm power spectrum upper limits Open
We present a Bayesian jackknife test for assessing the probability that a data set contains biased subsets, and, if so, which of the subsets are likely to be biased. The test can be used to assess the presence and likely source of statisti…
View article: Characterization Of Inpaint Residuals In Interferometric Measurements of the Epoch Of Reionization
Characterization Of Inpaint Residuals In Interferometric Measurements of the Epoch Of Reionization Open
Radio Frequency Interference (RFI) is one of the systematic challenges preventing 21cm interferometric instruments from detecting the Epoch of Reionization. To mitigate the effects of RFI on data analysis pipelines, numerous inpaint techni…
View article: Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum
Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum Open
Combining the visibilities measured by an interferometer to form a cosmological power spectrum is a complicated process. In a delay-based analysis, the mapping between instrumental and cosmological space is not a one-to-one relation. Inste…