Date: 2026-04-17
Time: 11:00 am [Note the time change]
Venue: Room 1.35, Department of Physics and Astronomy, UWC and Zoom
Format: In-person hybrid
(While the hybrid option is available, we strongly encourage in-person attendance!)
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Speaker: Junaid Townsend
Affiliation: University of the Western Cape, Cape Town.
Title: Probing Cosmology with the MeerKAT Interferometer
Abstract:
Line intensity mapping is a novel technique for probing the large-scale structure of the Universe by measuring the aggregate emission of spectral lines without resolving individual sources. In this talk, I will present an HI intensity mapping analysis using 17.45 hours of MeerKAT's MIGHTEE Survey data on the COSMOS field. With this data set, the HI power spectrum is measured over the frequency range 1332–1392 MHz (0.02 ≤ z ≤ 0.066), and after mitigating broadband contamination via outlier flagging, the cross-correlation of time-split visibilities yields a statistically significant detection across the scales 3 ≲ k ≲ 20 Mpc⁻¹, with a signal-to-noise ratio of ~13. This is compared to the HI power spectrum estimated from an HI galaxy catalogue extracted from the same data, field, and redshift range — testing whether intensity mapping can recover the total HI content and whether the catalogue captures all the HI in this volume. The two power spectra are consistent within 1–2σ of their respective uncertainties and the same orders of magnitude (~10⁻² – 10⁻¹ Mpc³ mK²). Further, a statistically significant correlation is observed between the visibility data and simulated visibilities using the detected galaxies as input. Together, these results provide a self-consistent validation of interferometric HI intensity mapping at low redshift, in agreement with galaxy-based measurements within the same cosmological volume.
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Date: 2026-03-27
Speaker: Jespere Nzobadila Ondze
Affiliation: University of the Western Cape, Cape Town.
Title: Searching for new physics with 136Xe neutrinoless double beta decay
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Date: 2026-03-20
Speaker: Prof. Malik Maaza
Affiliation: UNISA, Pretoria and iThemba LABS, NRF, South Africa.
Title: Room temperature Quantum mechanics peculiarities in nanoscaled systems
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Date: 2026-02-27
Speaker: Dr. Steven Murray
Affiliation: Stellenbosch University, Stellenbosch, South Africa.
Title: First Results from HERA Phase II
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Date: 2026-02-18
Speaker: Dr. Chenoa Tremblay
Affiliation: The SETI Institute, United States.
Title: Billions of Stars, One Question: Radio Astronomy and the Search for Life.
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Date: 2026-02-06
Speaker: Prof. Patrick Dorey
Affiliation: Department of Mathematical Sciences, Durham University, Durham, United Kingdom
Title: the ODE/IM correspondence
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Date: 2025-11-21
Speaker: Prof. André Ferrari
Affiliation: Observatoire de la Côte d'Azur, Nice, France
Title: Detection of Fast Radio Bursts using a hybrid neural architecture
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Date: 2025-11-07
Speaker: Geoff Murphy
Affiliation: Department of Physics and Astronomy, University of the Western Cape (UWC)
Title: High-dimensional Bayesian modelling approaches for 21cm cosmology
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Date: 2025-10-31
Speaker: Dr Verlon Etsebeth
Affiliation: Department of Physics and Astronomy, University of the Western Cape (UWC)
Title: Astronomaly: From Large-Scale Anomaly Detection to Targeted Discovery
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Date: 2025-10-17
Speaker: Bhivek Singh
Affiliation: Department of Physics and Astronomy, University of the Western Cape (UWC)
Title: Unmasking Anomalies: The Puzzle of Second Class Currents in 22Na
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Date: 2025-10-10
Speaker: Prof. D.J. Pisano
Affiliation: Department of Astronomy, University of Cape Town (UCT), Cape Town, South Africa
Title: Probing the Magneto-Ionized Circumgalactic Medium of M31 with HI and Rotation Measures
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Date: 2025-10-03
Speaker: Daniel Johnson
Affiliation: Laboratoire Univers et Particules de Montpellier (LUPM), Université de Montpellier, Montpellier, France
Title: Strong lensing, cosmology, and the line of sight
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Date: 2025-08-29
Speaker: Mohamed Kamil
Affiliation: Department of Physics and Astronomy, University of the Western Cape (UWC)
Title: From novae to neutrinos: Insights from neutron-removal reactions
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Date: 2025-07-18
Speaker: Dr Julien Larena
Affiliation: Laboratoire Univers et Particules de Montpellier (LUPM), Université de Montpellier, Montpellier, France
Title: Cosmology with Einstein rings; a path to a 6x2pt analysis
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Date: 2025-06-13
Speaker: Dr Aman Chokshi
Affiliation: McGill University, Montreal, Canada
Title: Towards an Epoch of Reionization Detection — Challenges in a Pre-SKA Era
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Date: 2025-06-11
Speaker: Dr Santiago Avila
Affiliation: Centro de Investigaciones Eneréticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
Title: Implications of cosmological expansion models from the final Dark Energy Survey BAO and SN data
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Date: 2025-05-30
Speaker: Prof. Andrei Albert Mesinger
Affiliation: Classe di scienze, Scuola Normale Superiore, Pisa, Italy
Title: Status and future of 21-cm cosmology during the first billion years
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Date: 2025-05-23
Speaker: Prof. Roy Maartens
Affiliation: Department of Physics and Astronomy, University of the Western Cape (UWC)
Title: Covariant Cosmography: a new perspective on H0 and the local Universe
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Date: 2025-04-25
Speaker: Dr Sthabile Kolwa
Affiliation: University of South Africa (UNISA), Pretoria, South Africa
Title: A MIGHTEE view of radio emission in faint AGN and star-forming galaxies
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Date: 2025-04-14
Speaker: Dr Chris Gordon
Affiliation: School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
Title: How Stars May Shred Axion Minihalos and What That Means for Dark Matter Searches