657 citations · 5.3k across the 114 of their papers we have counts for
115 papers
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…
New techniques for high-resolution imaging and high-precision wavefront sensing via masked-aperture interferometry
Nithyanandan Thyagarajan, Bojan Nikolic, Chris Carilli +2
Achieving high-angular-resolution imaging on subarcsecond scales is fundamentally limited by wavefront aberrations imparted by the propagation medium and by optical elements along…
Capabilities and Limitations of Non-Redundant Aperture Interferometry for Beam Size Measurements
C. Carilli, U. Iriso, B. Nikolic +3
Non-Redundant Aperture Interferometry (NRAI) is a beam characterization technique developed at ALBA in collaboration with radio-astronomy institutes. It enables the single-acquisit…
Forest without Trees is still Fruitful: Constraints on the thermal state of the neutral IGM at with the 21-cm forest power spectrum
Tomáš Šoltinský, Arnab Chakraborty, Girish Kulkarni +10
Neutral regions of the intergalactic medium (IGM) during the Epoch of Reionization (EoR) remain largely unexplored due to the limitations of existing probes. Owing to discoveries o…
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…
Establishing a relationship between the cosmological 21 cm power spectrum and interferometric closure phases
Pascal M. Keller, Bojan Nikolic, Nithyanandan Thyagarajan
Measurements of the cosmic 21 cm signal need to achieve a high dynamic range to isolate it from bright foreground emissions. Calibration inaccuracies can compromise the spectral fi…
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…
Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-Point Statistics
Honggeun Kim, Jacqueline N. Hewitt, Nicholas S. Kern +61
Measuring one-point statistics in redshifted 21 cm intensity maps offers an opportunity to explore non-Gaussian features of the early universe. We assess the impact of instrumental…
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…
Estimating Soil Electrical Parameters in the Canadian High Arctic from Impedance Measurements of the MIST Antenna Above the Surface
I. Hendricksen, R. A. Monsalve, V. Bidula +13
The MIST experiment aims to detect the cosmological 21-cm signal through sky observations at 25-125 MHz using a wide-beam antenna. The antenna is mounted above the soil and the bea…
Two-dimensional Light Beam Shape Characterization using Interferometric Closure Amplitudes
Nithyanandan Thyagarajan, Bojan Nikolic, Chris Carilli +2
We introduce a novel technique using closure amplitudes, inspired by radio interferometry, to determine with high angular resolution the two-dimensional profile of a light beam usi…
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…
A New Method for Wavefront Sensing using Optical Masking Interferometry
C. L. Carilli, L. Torino, B. Nikolic +2
Wave front sensing of the surface of equal phase for a propagating electromagnetic wave is a vital technology in fields ranging from real time adaptive optics, to high accuracy met…
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…
The CRAFT Coherent (CRACO) upgrade I: System Description and Results of the 110-ms Radio Transient Pilot Survey
Z. Wang, K. W. Bannister, V. Gupta +40
We present the first results from a new backend on the Australian Square Kilometre Array Pathfinder, the Commensal Realtime ASKAP Fast Transient COherent (CRACO) upgrade. CRACO rec…
New interferometric aperture masking technique for full transverse beam characterization using synchrotron radiation
Ubaldo Iriso, Laura Torino, Chris Carilli +2
Emittance measurements using synchrotron radiation are usually performed using x-rays to avoid diffraction limits. Interferometric techniques using visible light are also used to m…
21cm Epoch of Reionisation Power Spectrum with Closure Phase using the Murchison Widefield Array
Himanshu Tiwari, Nithyanandan Thyagarajan, Cathryn M. Trott +1
The radio interferometric closure phases can be a valuable tool for studying cosmological {H\scriptsize{I}}~from the early Universe. Closure phases have the advantage of being immu…
Laboratory Demonstration of Image-Plane Self-Calibration in Interferometry
Christopher L. Carilli, Bojan Nikolic, Laura Torino +2
We demonstrate the Shape-Orientation-Size conservation principle for a 3-element interferometer using aperture plane masking at the ALBA visible synchrotron radiation light source.…
Two-dimensional Synchrotron Beam Characterisation from a Single Interferogram
Bojan Nikolic, Christopher L. Carilli, Nithyanandan Thyagarajan +2
Double-aperture Young interferometry is widely used in accelerators to provide a one-dimensional beam measurement. We improve this technique by combining and further developing tec…
Radio-loud fraction of z>6 quasars
Pascal M. Keller, Nithyanandan Thyagarajan, Ajay Kumar +2
Quasars at redshifts are an excellent probe of the formation and evolution of supermassive black holes in the early Universe. The population of radio-luminous quasars is of p…