CSIRO S&A Interferometry Discussion Forum
Organiser: Nithyanandan Thyagarajan
This is a discussion forum for bringing historic/current/advanced/interesting topics on interferometry to the table. The scope is intended to be broad (beyond any specific instruments) and is open especially to discussing theories off-mainstream interferometry, built-in assumptions and consequences when they break down, where the limitations and bottlenecks lie, and connections to how interferometry is used in other fields. It is hoped that this will infuse new ideas into the mix that can be taken forward practically.
Clearly, there could be immediate relevance for SKA and ASKAP. For instance, with the SKA and ASKAP expected to make significant strides in the coming years, gaining a fundamental understanding of the radio signals and their passage through the analog and digital systems will be essential for making novel design choices, creating innovation in systems and analysis techniques, and widening the science possible using this knowledge. However, the scope of this forum is not intended to be restricted to specific telescope systems and it is about seeking a deeper understanding of fundamentals that can contribute effectively to more novel and advanced systems of the future.
Initially, we will meet once a fortnight and increase the meeting frequency depending on interest and demand. The format is intended to be flexible and interactive. In a typical one-hour meeting, the first 30 mins would be focused on a specific topic including discussion, which could be something the lead presenter/participants have expertise in, want expert opinion on, or an interesting paper they came across that could be of wider interest. The discussions would be of a whiteboard/free-form style, rather than a full-fledged presentation (occasionally, we could get internal/external experts to give a presentation).
Interferometry Meeting Series 2024
| # | Date | Topic | Discussion Leader(s) | Notes/Slides | Recording | Additional resources |
| 31 | 2024-02-20 | Chromatic aberration in radio telescopes: application to SKA/AAVS and CryoPAF | Lister Staveley-Smith | LSS slides | Recording |
Interferometry Meeting Series 2023
| # | Date | Topic | Discussion Leader(s) | Notes/Slides | Recording | Additional resources |
| 30 | 2023-12-19 | Modern approaches to astrometry | Richard Dodson | Recording | ||
| 29 | 2023-12-05 | Overview and Progress of AAVS2/AAVS3 | Charlotte Sobey | Recording | ||
| 28 | 2023-11-21 | ASKAP bright source handling | John Morgan | Recording | ||
| 27 | 2023-11-07 | Image reconstruction using closure invariants and Machine Learning | Nithyanandan Thygarajan | Recording | [1] Interferometric Image Reconstruction using Closure Invariants and Machine Learning: Thyagarajan et al. (2023), arXiv:2311.06349 | |
| 26 | 2023-10-24 | ASKAP polarisation handling | Alec Thomson | Recording | ||
| 25 | 2023-10-10 | Reduced resolution beamforming | Danny Price | Recording | ||
| 24 | 2023-09-12 | A primer on polarisation | Rick Perley | RP slides | Recording | |
| 23 | 2023-08-29 | Societal applications of interferometry | George Hobbs | GH slides (priv.) | Recording (priv.) | |
| 22 | 2023-08-15 | Hybrid architectures for fast imaging with large-N multi-scale aperture arrays | Nithyanandan Thyagarajan | NT slides | Recording |
[1] Optimization and commissioning of the EPIC commensal radio transient imager for the long wavelength array: Krishnan et al. (2023), MNRAS, 520, 1928 [2] A Generic and Efficient E-field Parallel Imaging Correlator for Next-Generation Radio Telescopes: Thyagarajan et al (2017), MNRAS, 467, 715 [3] Enabling Next-Generation Dark Energy and Epoch of Reionization Radio Observatories with the MOFF Correlator: Morales (2011), PASP, 123, 1265 |
| 21 | 2023-08-01 | Miscellaneous discussions -- ASKAP beamforming and new calibration ideas | Group | Recording | ||
| 20 | 2023-07-18 | Managing Solar Activity in ASKAP Imaging | Alec Thomson, John Morgan, Rajan Chhetri, and others | Recording | ||
| 19 | 2023-01-31 | Synchrotron Radiation Interferometry for Determining Particle Beam Shape | Nithyanandan Thyagarajan | Recording |
[1] Measurement of Small Transverse Beam Size using Interferometry -- Mitsuhashi (2001) [2] Two-dimensional Visible Synchrotron Light Interferometry for Transverse Beam-profile Measurement at the SPring-8 Storage Ring -- Masaki & Takano (2003) [3] Transverse Beam Profile Reconstruction using Synchrotron Radiation Interferometry -- Torino & Iriso (2016) |
Interferometry Meeting Series 2022
| # | Date | Topic | Discussion Leader(s) | Notes/Slides | Recording | Additional resources |
|---|---|---|---|---|---|---|
| 18 | 2022-12-06 | Space surveillance using near-field imaging | Steve Prabu | SP slides | Recording | [1] A near-field treatment of aperture synthesis techniques using the Murchison Widefield Array: Prabu et al. (2023), PASA, 40, 056 |
| 17 | 2022-11-22 | A direct imaging architecture for large-N arrays | Nithyanandan Thyagarajan | NT slides | Recording |
[1] A Generic and Efficient E-field Parallel Imaging Correlator for Next-Generation Radio Telescopes: Thyagarajan et al (2017), MNRAS, 467, 715 [2] Enabling Next-Generation Dark Energy and Epoch of Reionization Radio Observatories with the MOFF Correlator: Morales (2011), PASP, 123, 1265 |
| 16 | 2022-08-30 | Interferometric imaging without Fourier transforms |
Chris Carilli Nithyanandan Thyagarajan |
CC slides | Recording |
[1] Image-plane Self-calibration in Interferometry: Carilli, Nikolic & Thyagarajan (2022), JOSA-A, 39, 2214 [2] A geometric view of closure phases in interferometry: Thyagarajan & Carilli, 2022, PASA, 39, e014 |
| 15 | 2022-08-16 |
Geometry of Closure Phase: A Basis for Image-Plane Self-Calibration |
Nithyanandan Thyagarajan | NT slides | Recording | [1] A geometric view of closure phases in interferometry: Thyagarajan & Carilli, 2022, PASA, 39, e014 |
| 14 | 2022-08-02 | Source Noise, Intensity Interferometry, and coherence | John Morgan | JM slides | Recording | [1] Source noise measurement and implications at low frequencies: Morgan & Ekers (2021), PASA, 38, e013 |
| 13 | 2022-07-05 | History of Aperture Synthesis in Radio Astronomy (Part 2) | Ron Ekers | RE slides | Recording | [1] For a history of medical imaging, see: Webb, S. From the Watching of Shadows: Origins of Radiological Tomography, Taylor & Francis Ltd, London, UK (1990) |
| 12 | 2022-06-07 | History of Aperture Synthesis in Radio Astronomy (Part 1) | Ron Ekers | RE slides | Recording | [1] For a history of medical imaging, see: Webb, S. From the Watching of Shadows: Origins of Radiological Tomography, Taylor & Francis Ltd, London, UK (1990) |
| 11 | 2022-05-24 | Interferometry at short baselines with SITARA | Jishnu Nambissan | JN slides | Recording |
[1] Presley et al. (2015), ApJ, 809, 18 [2] Singh et al. (2015), ApJ, 815, 88 [3] Thyagarajan et al. (2015a), ApJ, 804, 14 [4] Thyagarajan et al. (2015b), ApJL, 807, L28 [5] Venumadhav et al. (2016), ApJ, 826, 116 |
| 10 | 2022-05-10 | Spherical harmonic all-sky imaging using wide-field transit interferometers | Mike Kriele | MK slides | Recording |
[1] Spherical Harmonics Overview (first 5 sections) by Volker Schönefeld (2005)
[2] The m-mode imaging formalism by Richard Shaw et al. (2014), ApJ, 781, 57
[3] Imaging OVRO-LWA data with m-modes by Eastwood et al. (2018), AJ, 156, 32
[4] Imaging EDA2 data with m-modes by Kriele et al. (2022), PASA, 39, e017
|
| 9 | 2022-04-26 | Joint mosaicking techniques for interferometric and single dish data |
Lister Staveley-Smith Nickolas Pingel |
Recording |
[1] NRAO Synthesis Imaging Summer School Lecture Notes, B. Mason [2] "Joint Deconvolution Algorithm to Combine Single-dish and Interferometer Data" by U. Rau et al. (2019), AJ, 158, 3 |
|
| 8 | 2022-04-12 | SKA-low Station Performance | Ravi Subrahmanyan | RS slides | Recording | |
| 7 | 2022-03-29 | Wide-field imaging algorithms | Daniel Mitchell | DM slides | Recording |
[1] Synthesis Imaging in Radio Astronomy - II, chapter 14, “Wide Field Imaging II: Imaging with Non-Coplanar Arrays”, R. Perley. [2] "Wide field imaging for the Square Kilometre Array" by Cornwell et al. (2012), SPIE, 8500, 0L [3] WSCLEAN by Offringa et al. (2014), MNRAS, 444, 606 |
| 6 | 2022-03-15 | Coherent detection pipeline for FRBs with ASKAP (CRACO) | Keith Bannister | KB slides | Recording | |
| 5 | 2022-02-01 | Measuring the monopole emission with interferometer using lunar occultation | Ben McKinley | BM slides | Recording |
[1] Vedantham et al. (2015), MNRAS, 450, 2291 [2] McKinley et al. (2018), MNRAS, 481, 5034 |
Interferometry Meeting Series 2021
| # | Date | Topic | Discussion Leader(s) | Notes/Slides | Recording | Additional resources |
|---|---|---|---|---|---|---|
| 4 | 2021-12-07 | Re-analysis of EHT M87 data | Nithyanandan Thyagarajan | Recording | ||
| 3 | 2021-11-09 | Short spacing with scanning interferometer |
John Bunton Nithyanandan Thyagarajan |
JB slides (priv.) |
Recording Part 2 (priv.) |
[1] Ekers & Rots (1979), ASSL, 76, 61 |
| 2 | 2021-10-26 | Coherence in radio interferometry: assumptions and implications | Nithyanandan Thyagarajan | NT notes | Recording |
[1] Chapter 5 on “Coherence of optical waves” in “Statistical Optics” by Joseph W. Goodman [2] Chapter 10 on “Interference and diffraction with partially coherent light” in “Principles of optics” by Born and Wolf [3] Chapter 15 on “Van Cittert–Zernike Theorem, Spatial Coherence, and Scattering” in TMS 2017 [4] Cornwell, Anantharamaiah, and Narayan (1989), “Propagation of coherence in scattering: an experiment using interplanetary scintillation“, JOSA-A, 6, 977 |
| 1 | 2021-10-12 | Fourier transforms in radio interferometry and related assumptions | Nithyanandan Thyagarajan | NT notes | Recording |
[1] Chapter 1 -- Synthesis Imaging in Radio Astronomy II (SIRA II) [2] Chapter 3 -- Interferometry and Synthesis in Radio Astronomy (TMS 2017) |