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8th of May 2024
Mini-symposium speaker Anna Scaife. Mini-symposium speaker Jayaram Chengalur. Mini-symposium speaker Scott Ransom.
ATNF Colloquium
Special mini-symposium
This week a special mini-symposium will be held in-person at Marsfield, and on-line, with the three international members of the ATNF Steering Committee each giving a short presentation.

Anna Scaife (Uni of Manchester)
"Scaling laws and self-supervised learning in AI for astrophysics."
As the current trend in deep-learning tends towards more data, more compute and more parameters, we ask: how large can astrophysical deep-learning models get? Using the largest dataset of labelled astronomy data available, we examine the scaling laws for supervised problems in astrophysics and conclude that self-supervised learning is a more promising direction for large-scale deep-learning in astronomy given the available label volumes; however, we also conclude that using in-domain (astronomy) data for pre-training results in better performance for the down-stream tasks from these self-supervised representations. Finally, I will show how we are building self-supervised foundation models for radio astronomy and a variety of the downstream tasks where we have applied them in practice.

Jayaram Chengalur (TIFR)
"The evolution of the HI content of galaxies"
Over cosmic time, galaxies grow by merger, and/or by the accretion of matter via inflows. As galaxies evolve they also convert their gas into stars. On a cosmic scale, it is well established that the star formation peaked about 10 billion years ago and that the average star formation rate per unit volume has declined sharply since then. Hydrogen is dominant baryonic component of galaxies, and atomic hydrogen is also the primary fuel for star formation. Stars form as the gas cools to become molecular hydrogen, and then cools further and collapses into stars under self gravity. Understanding the evolution of the atomic hydrogen content of galaxies is hence key to understanding the evolution of the star formation rate with cosmic time. The recent upgrade to the Giant Metrewave Radio Telescope (GMRT), has allowed significant progress to be made in observing HI in galaxies at redshifts around 1 using the stacking method. In this talk, I will discuss some of the results from ongoing atomic hydrogen surveys of star forming galaxies using the upgraded GMRT.

Scott Ransom (NRAO)
"New Exotic and Massive Pulsars in Globular Clusters"
In the past five years, the number of known globular cluster pulsars, most of them of the millisecond variety, has blossomed by more than 130 to a total of over 300. The main reasons were the commissioning of the extremely sensitive FAST and MeerKAT radio telescopes, and increased computing power applied to the searches themselves. In this talk I'll mention some of the fascinating exotic systems that have been found, discuss the importance of long-term timing of these systems, and hint at the astrophysics and basic physics those systems will provide.

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