657 citations · 5.3k across the 114 of their papers we have counts for
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A fast, wide-field, and real-time imaging prototype for large aperture arrays
Nithyanandan Thyagarajan, Jishnu Thekkeppattu, David Humphrey
Real-time processing on sub-millisecond timescales is essential for detecting fast astrophysical transients such as fast radio bursts (FRBs) and prompt electromagnetic counterparts…
Towards independent event horizon imaging of the supermassive black holes in M87 and the Milky Way
Nithyanandan Thyagarajan, Samuel Lai, Ivy Wong +1
The Event Horizon Telescope (EHT) Collaboration's images of the supermassive black holes in M87 and the Milky Way have provided the first event-horizon-scale views of these objects…
Conditional Image Diffusion with Interferometric Closure Invariants: Independent EHT Imaging of Centaurus~A and 3C~279
Samuel Lai, Nithyanandan Thyagarajan, O. Ivy Wong +1
We present independent imaging analyses of Event Horizon Telescope (EHT) observations of the active galactic nuclei in radio galaxy Centaurus~A and quasar 3C~279 using Generative D…
The FarView Low Frequency Radio Array on the Moon's Far Side: Science and Array Architecture
Jack O. Burns, Judd Bowman, Tzu-Ching Chang +8
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 f…
A New Method for Aperture Masking Interferometric Imaging: Demonstration with the JWST
Christopher Carilli, Bojan Nikolic, Laura Torino +2
We present a new method for aperture masking interferometric (AMI) imaging at near-IR wavelengths using radio astronomical techniques. The method starts with derivation of interfer…
Very-Long Baseline Interferometry Imaging with Closure Invariants using Conditional Image Diffusion
Samuel Lai, Nithyanandan Thyagarajan, O. Ivy Wong +1
Image reconstruction in very-long baseline interferometry operates under severely sparse aperture coverage with calibration challenges from both the participating instruments and p…
Identifying Habitable Exoplanets with Radio Telescopes on the Lunar Farside
N. Mahesh, J. D. Bowman, J. O. Burns +11
The search for habitable conditions beyond Earth is a top priority in astrophysics. The discovery of habitable exoplanets beyond our solar system will require a suite of instrument…
Using the antenna impedance to estimate soil electrical parameters for the MIST global 21-cm experiment
Cinthia Altamirano, Ricardo Bustos, Raul A. Monsalve +11
Radio experiments trying to detect the global ~cm signal from the early Universe are very sensitive to the electrical properties of their environment. For ground-based experime…
Comparison of Fast, Hybrid Imaging Architectures for Multi-scale, Hierarchical Aperture Arrays
Nithyanandan Thyagarajan
Two major areas of modern radio astronomy, namely, explosive astrophysical transient phenomena and observations of cosmological structures, are driving the design of aperture array…
Deep Learning VLBI Image Reconstruction with Closure Invariants
Samuel Lai, Nithyanandan Thyagarajan, O. Ivy Wong +2
Interferometric closure invariants, constructed from triangular loops of mixed Fourier components, capture calibration-independent information on source morphology. While a complet…
Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning
Lindsay M. Berkhout, Daniel C. Jacobs, Zuhra Abdurashidova +93
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 m…
matvis: A matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays
Piyanat Kittiwisit, Steven G. Murray, Hugh Garsden +95
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 a…
Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data
Geoff G. Murphy, Philip Bull, Mario G. Santos +76
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 reflect…
Direct Optimal Mapping Image Power Spectrum and its Window Functions
Zhilei Xu, Honggeun Kim, Jacqueline N. Hewitt +79
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 op…
Interferometric Image Reconstruction using Closure Invariants and Machine Learning
Nithyanandan Thyagarajan, Lucas Hoefs, O. Ivy Wong
Interferometric closure invariants encode calibration-independent details of an object's morphology. Excepting simple cases, a direct backward transformation from closure invariant…
Simulating the Detection of the Global 21 cm Signal with MIST for Different Models of the Soil and Beam Directivity
Raul A. Monsalve, Christian H. Bye, Jonathan L. Sievers +10
The Mapper of the IGM Spin Temperature (MIST) is a new ground-based, single-antenna, radio experiment attempting to detect the global 21 cm signal from the Dark Ages and Cosmic Daw…
Mapper of the IGM spin temperature: instrument overview
R. A. Monsalve, C. Altamirano, V. Bidula +17
The observation of the global 21 cm signal produced by neutral hydrogen gas in the intergalactic medium (IGM) during the Dark Ages, Cosmic Dawn, and Epoch of Reionization requires…
Measuring the global 21-cm signal with the MWA-II: improved characterisation of lunar-reflected radio frequency interference
Himanshu Tiwari, Benjamin McKinley, Cathryn M. Trott +1
Radio interferometers can potentially detect the sky-averaged signal from the Cosmic Dawn (CD) and the Epoch of Reionisation (EoR) by studying the Moon as a thermal block to the fo…
Bayesian jackknife tests with a small number of subsets: Application to HERA 21cm power spectrum upper limits
Michael J. Wilensky, Fraser Kennedy, Philip Bull +2
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 b…
Image-Plane Self-Calibration in Interferometry
C. L. Carilli, B. Nikolic, N. Thyagarajan
We develop a new process of image plane self-calibration for interferometric imaging data. The process is based on Shape-Orientation-Size (SOS) conservation for the principal trian…
Characterization Of Inpaint Residuals In Interferometric Measurements of the Epoch Of Reionization
Michael Pagano, Jing Liu, Adrian Liu +75
Radio Frequency Interference (RFI) is one of the systematic challenges preventing 21cm interferometric instruments from detecting the Epoch of Reionization. To mitigate the effects…
Automated Detection of Antenna Malfunctions in Large-N Interferometers: A Case Study with the Hydrogen Epoch of Reionization Array
Dara Storer, Joshua S. Dillon, Daniel C. Jacobs +75
We present a framework for identifying and flagging malfunctioning antennas in large radio interferometers. We outline two distinct categories of metrics designed to detect outlier…
Invariants in Co-polar Interferometry: an Abelian Gauge Theory
Nithyanandan Thyagarajan, Rajaram Nityananda, Joseph Samuel
An -element interferometer measures correlations among pairs of array elements. Closure invariants associated with closed loops among array elements are immune to multiplicative…
Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline
James E. Aguirre, Steven G. Murray, Robert Pascua +73
We describe the validation of the HERA Phase I software pipeline by a series of modular tests, building up to an end-to-end simulation. The philosophy of this approach is to valida…