TBD

Ashwathi Nair MCR Review

Probing the cosmic web with Fast Radio Bursts

Improving tests of fundamental physics with Very Long Baseline Interferometry of millisecond pulsars.

TBD

The dark energy which fills the Universe appears to be evolving with time, according to recent results published by the Dark Energy Spectroscopic Instrument (DESI) collaboration, in a joint analysis with supernova datasets. In this talk I will discuss: What is DESI? How does it measure the effect of dark energy? What does it mean for the properties of dark energy to "evolve", and is this related to the more famous "Hubble tension"? And what should we make of these intriguing results?

Cold (<100 K) gas and dust are essential ingredients for galaxies to form stars. Over the last two decades, constraining gas and dust content has been one of the key scientific drivers of submm/mm interferometry observations (such as the Atacama Large Millimeter/submillimeter Array (ALMA) and Northern Extended Millimeter Array (NOEMA)). Meanwhile, the James Webb Space Telescope (JWST) starts unveiling more quiescent (massive) galaxies at z>3 and allows a detailed study of z>~1.5 quiescent galaxies more efficiently. Intriguingly, not all of these quiescent galaxies are devoid of gas and dust. In this talk, I will talk about gas and dust measurements in star-forming and quiescent galaxies in the early universe (z~1 or higher, or when the age of the universe was less than ~ 6 Gyrs) and the implications. The talk will also cover a recent effort of ALMA archival data mining, called ECOGAL (ECOology for Galaxies using ALMA archive and Legacy surveys), to improve the current gas scaling relation – gas depletion time scale as a function of stellar mass, redshift and deviation from the main sequence – across cosmic time and space.

Saurav CoC review.

Saurav's CoC committee meeting

I will discuss some of the major ideas behind galaxy formation
simulations. Detailed numerical simulations are critical to interpret and
understand observations. Unfortunately, simulations are sensitive to feedback
implementations. Interactions at wind/halo gas interfaces in the CGM occur on
scales that are much below the resolution of any current or near future galaxy
formation simulation, making a "brute force" approach not viable. To mitigate
this impasse implemented a new wind algorithm, Physically Evolved Winds (PhEW),
which explicitly models the "subgrid physics" in the wind-halo gas interaction
within a simulation, tuned to very high resolution simulations of clouds moving
through the CGM/IGM, using the cosmological simulation to provide the physical
characteristics that informs the interaction. Previous simulations using more
standard wind model approaches reproduce many observed properties of galaxies
but our new wind implementation allows us to tie empirical successes, and
failures, more securely to the underlying wind physics and to make more robust
predictions. I will show the first results of simulations using this new
feedback method, whose results are much more robust to changes in the hydro
method and numerical resolution.

https://swinburne.zoom.us/j/81452278865?pwd=M0m1ho7TNBCPkRb6ElMIxPIIgMbC8G.1
Password: 523082

Searching for Fast Radio Bursts with ASKAP

We use state-of-the-art cosmological hydrodynamical simulations of galaxies to study recent ‘hot topics’ in galaxy formation at the smallest scales: the existence of low-surface-brightness, ultra diffuse galaxies, and the role of AGN feedback in the evolution of dwarfs.

Understanding dark matter and dark energy, which make up 95% of the Universe, requires cosmological surveys to achieve percent-level precision. Yet, this precision reveals tensions between observations and the standard cosmological model, potentially stemming from systematic biases. CLONES (Constrained LOcal & Nesting Environment Simulations) are digital twins of the local Universe designed to replicate our cosmic environment and tackle these challenges. Highlighting key cosmological tensions and showcasing a few example studies of these CLONES will demonstrate how they can offer a powerful framework for bias-free analyses, advancing our understanding of galaxy evolution and large-scale structure formation.

Using state-of-the-art reduction methods, we analyze the new JWST data acquired by the NIRISS/NIRCam wide-field slitless spectroscopy (WFSS) and NIRSpec in both the multi-object spectroscopy (MOS) and slit-stepping modes. These complementary spectroscopic data sets obtained from multiple instruments open up key window on unbiased investigation of star formation, feedback, and ISM properties in and beyond the cosmic noon epoch. We bring forth the first spatially resolved analysis of high-redshift galaxies with JWST WFSS and measure the first gas-phase metallicity radial gradient with sub-kpc resolution at z?3. We extend such analysis to galaxies in the epoch of reionization, finding a swift mode transition of galaxy mass assembly and chemical enrichment in the early Universe. We invent a novel methodology of conducting 3D spectroscopy of galaxies by stepping the NIRSpec slits across their surfaces, obtaining resolved chemical and dynamical properties for a sample of 26 galaxies at z~1 and finding clear evidence for strong rotational support in galaxies showing negative metallicity gradients. Using the NIRSpec MOS in prism mode, we discover one of the highest redshift galaxies, spectroscopically confirmed at z=8.16, with PopIII-like stellar populations. This galaxy candidate hosting the first generation stars opens up new key frontiers on galaxy evolution and stellar physics in the early Universe.