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Upcoming Seminars

The BOAT that rocked: the afterglow of GRB 221009A

  Speaker 

Dr. Lauren Rhodes

McGill University

(Canada)
Time Thursday 1st May, 2pm
Location   B106-Beech Hill

GRB 221009A has been dubbed the BOAT or brightest of all time for its record-breaking gamma-ray brightness. At radio frequencies, it is also the brightest radio counterpart detected to date. In this talk, I will present a summary of the observations conducted by my collaborators and I (Bright & Rhodes et al 2023, Fulton et al 2023, Rhodes et al 2024), resulting in comprehensive multi-wavelength coverage including the most detailed radio study of any GRB to date. Our radio campaign spanned over three orders of magnitude in frequency space starting a few hours post burst and continuing to this day. I will discuss the importance of such coverage for theoretical modelling and our understanding of jet geometry. Finally, I will present a brief overview of our plans to continue monitoring this fascinating object.

Ionic Liquids: Applications in Protein Kinetics, Dynamics and Aggregation

  Speaker 

Prof. Harekrushna Sahoo

National Institute of Technology

(Roukela, IND)
Time Friday 7th March, 10am
Location   Conway Lecture Theatre
Herein, we used secondary structure, local amino acid environment and confocal microscopy to analyse the impact of different ionic liquids (i.e. both saturated and unsaturated) on the unfolding/refolding processes along with the aggregation and disaggregation of different proteins. Our findings demonstrate the importance of the hydrophobicity of the ionic liquids on the unfolding and refolding kinetics as well as the aggregation and disaggregation propensities. It is observed that higher hydrophobicity of the ammonium-based ionic liquid (specifically) enhances the thermal-dependent protein refolding whereas, the stabilisation is observed to be reliant on the IL concentrations. Additionally, synchronous, temperature-dependence and ANS-probed fluorescence measurements are employed to interpret the protein's conformational changes of the protein in the specific ionic liquid medium. Ionic liquids with higher hydrophobic chains (long alkyl chain) promote aggregation whereas short chain ILs assists in protein disaggregation of aggregates. The current work is effective in understanding and establishing a benchmark on IL-mediated protein kinetics and dynamics beyond the stability and conformation.

High-Resolution Studies of the Inner Circumstellar Disks of Herbig Ae/Be Stars

  Speaker  Robin Mentel
University College Dublin
Time Thursday 13th February, 10:30am
Location  

PhD Defense.

Abstract:  Herbig Ae/Be stars constitute a fascinating bridge between low-mass and high-mass star formation. This talk present findings of the inner disk around these stars in order to characterise their environment using high-resolution optical and near-infrared spectroscopy. In a first project, the inner disk of the Herbig Ae star HD 141569 is studied with HI lines, showing that the disk is very compact, constrained within few stellar radii, and reaching very close to the star. This infers significant constraints on the nature of the disk winds around the star, and it's mass accretion mode. In a second project, the forbidden emission around a large sample of Herbig Ae/Be stars is studied. The results show a significant discrepancy to the emission from young low-mass stars, and shed light on the disk dispersal mechanisms around young intermediade-mass stars.

Finding Relativistic Stellar Explosions as Fast Optical Transients

  Speaker  Anna Ho
Cornell University 
Time Tuesday 14th January, 14pm
Location   B106 - Beech Hill
For the last half-century, relativistic outflows accompanying the final collapse of massive stars have predominantly been detected via high-energy emission, as long-duration gamma-ray bursts (GRBs). Yet, it has long been hypothesized that GRBs are the tip of the iceberg of relativistic stellar explosions. I will present results from a search for relativistic stellar explosions using optical time-domain surveys. The emerging zoo includes afterglows at cosmological distances with no detected GRB, supernovae with luminous X-ray and radio emission, and mysterious "fast blue optical transients" with minute-timescale optical flares at supernova-like luminosities. An understanding of the origin of these events and their relation to GRBs will be enabled by upcoming time-domain surveys in other bands, including X-ray, UV, and submillimeter.

Spatial and spectral characterization of micrometer scale soft x-ray emitting laser-produced plasmas

  Speaker  Kevin Mongey
University College Dublin
Time Tuesday 12th November, 9am
Location  

PhD Defence.

Abstract: n/a.

Archive of previous seminars: click here

UCD School of Physics

University College Dublin, Belfield, Dublin 4, Ireland.
T: +353 1 716 7777