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Jonathan Mackey > Research

Introduction to research topics and some results obtained

Computational Astrophysics Research Group

After joining DIAS in 2016 as a research fellow I have the opportunity to start a research group in computational astrophysics, focused on massive stars, their evolution and explosion. In 2017 the Irish Research Council funded two meetings, one at DIAS and a second at Armagh Observatory & Planetarium, to promote cross-border collaboration in this rapidly growing field of research.

Massive stars are few in number and short-lived but are nevertheless the main drivers of the evolution of gas in galaxies. They have strong stellar winds and emit ionising radiation, both of which heat the surrounding gas and drive strong outgoing shocks. When they reach the end of their lives, they explode as supernovae and/or gamma-ray bursts, heating the surroundings, driving strong shocks through nearby gas, enriching their environment with heavy elements, and their supernova remnants are important sites for acceleration of high-energy cosmic rays.

Quantitative modelling of most of these processes requires multi-dimensional simulations. By comparing our models to observed systems, we learn about the evolutionary history of stars, verifying and constraining stellar evolution models. We use these models to calculate the consequences of interactions of supernovae with their surroundings.

Group Members:

Maggie Goulden: Final year undergraduate at Trinity College Dublin, doing her Bachelor Project on stellar winds from evolved stars.
Sam Green: PhD student at DIAS since January 2017 working on simulations of stellar wind bubbles around massive stars.
Maria Moutzouri: PhD student at DIAS since October 2017 working on simulations and observations of non-thermal radio emission from jets and winds.
Erin Higgins: PhD student of Jorick Vink at Armagh Observatory and Planetarium since September 2016, co-supervised by JM. Working on stellar evolution calculations of massive stars in the Small Magellanic Cloud.

Former Members:

Robert Kavanagh: Summer undergraduate internship at DIAS in 2017, working on latitude-dependent winds from rapidly rotating stars. Now doing a PhD at Trinity College Dublin in the Cool Stars and Exoplanets group of Aline Vidotto.

Feedback from Massive Stars

NGC 6357 HST

Hubble Space Telescope image of Pismis 24 and NGC 6357, where winds and radiation from young massive stars are evaporating the cloud of gas they were born in.
[Image Credit: NASA, ESA, and J. Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain)]

Information about some projects pre-2016 can be found here.
PION Code Logo


pion is a grid-based fluid dynamics code for simulating the circumstellar medium around massive stars.
It has been used to study the expansion of photoionized HII regions around massive stars, stellar winds of hot and cool stars, and the evolution of supernova remnants.
More information here.

High-Energy Astrophysics

DIAS is a member of the High Energy Stereoscopic System (H.E.S.S.), one of the state-of-the-art Cherenkov telescope systems currently in operation around the world. It observes Cherenkov radiation emitted by high-energy particles in the Earth's upper atmosphere, produced when cosmic rays and gamma rays interact with the nuclei in the atmosphere.
The Cherenkov Telescope Array (CTA) is the next ground-based observatory for gamma-ray astronomy. It is a worldwide consortium of scientists and instititutions, and the aim is to build an observatory that is 10 times more sensitive than current facilities, coming online in the next few years.
CTA-Ireland is an association of scientists on the island of Ireland, whose objectives are to promote participation by Ireland in the CTA Consortium at all levels, scientific, industrial and political. DIAS is part of the CTA Consortium and of CTA-Ireland.
Our group contributes to H.E.S.S. and CTA-related research by making computer simulations of nebulae (wind bubbles, supernova remnants) that are known to accelerate particles, and calculating the thermal and non-thermal emission that they should produce.

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© Jonathan Mackey 2017. Last update: 2019-01-14