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Pathways towards forming super-massive black holes in the early Universe

Periodic Reporting for period 1 - SmartStars (Pathways towards forming super-massive black holes in the early Universe)

Reporting period: 2016-10-03 to 2018-10-02

"What is the problem being addressed?

The formation mechanisms of Super-Massive Black Holes (SMBHs) in our Universe is unknown. SMBHs shining as extremely luminous quasars are seen out to very large distance and hence time. The most distant quasar thus far observed has a ""redshift"" of z = 7.1 meaning it existed approximately 500 Myrs after the Big Bang. This project aims to explore a promising formation mechanism - the direct collapse mechanism which has the potential to explain the formation of the very first and possibly all SMBHs. Solving this outstanding problem in modern astrophysics would unlock a significant problem in modern day black hole and galaxy formation (which is thought to be regulated by black holes).

Why is it important for society?

We are addressing a knowledge gap in our understanding of how the Universe operates. As a species one of our greatest strengths is our ability to understand the Universe around us. This project is attempting to shed more likely on one of the deepest mysteries in astrophysics. Black hole formation is at present poorly understood. Their existence has been confirmed through detailed observations but solid theoretical grounds explaining their formation mechanisms is still lacking. This project directly addresses this problem and with it increases our understanding of the physics of the world and Universe we inhabit.

What are the overall objectives?

The overall objective is to create more detailed models of black hole formation in the early Universe. The models will help to elucidate the environmental conditions that lead to massive black hole formation.


During the course of the action I made significant progress in understanding the pathways available for SMBH formation. Early in the project I led a study showing that two galaxies forming close together in both time and space can lead to the formation of a direct collapse black hole with a seed mass sufficient to explain the origin of the most massive black holes. This research was published in Nature Astronomy and received world-wide attention both within academic circles and beyond. For a large portion of the project time I investigated the formation of super-massive stars which are though to be the progenitors of direct collapse black holes.I identified their fragmentation prospects, the formation of the first super-massive stars and their early evolution. I also investigated the initial stages of black hole formation subsequent to the collapse of the SMS. I found that powerful outflows (jets) launched by the accreting black hole regulate the average accretion rate onto the black hole to below the Eddington limit and hence present a barrier to super-Eddington accretion modes. Finally, I am the second author of another research project which has now been accepted for publication in Nature. In this research we investigate an alternate mode for forming super-massive stars in the early Universe which has the potential to open a new pathway to direct black hole formation."
"October 2016 - December 2016 (Q4 2016):
Participated in outreach event for Space Week in DCU. Gave a talk on Black Holes to an audience of approximately 200 people.
Published paper in MNRAS - GRACKLE: a chemistry and cooling library for astrophysics
Development of smartstar particle algorithm for Enzo code

January 2017 - March 2017 (Q1 2017)
Organised workshop on ""The Collapse of the First Objects"". Attended by astrophysicists from across Ireland, the UK and Germany.
Member of the planning committee for the ""New Foundations"" scheme - a joint North-South initiative for collaborations between academics in Northern and Southern Ireland.
Published paper in Nature Astronomy on ""synchronised"" formation of black holes in the early Universe.
Nature Astronomy article receives widespread attention worldwide with articles in major newspapers throughout Europe and the US.
I appeared on the scientific radio show - ""Futureproof"" describing the finding and describing the early Universe.
Feature article in Ireland's premier newspaper - The Irish Times - on my Marie Sklodowska-Curie Fellowship.
Secondment to University of Heidelberg (February 2017 - March 2017)

March 2017 - June 2017 (Q2 2017)
Published paper in MNRAS - An analytic resolution to the competition between Lyman-Werner radiation and metal winds in direct collapse black hole hosts
Attended Enzo Developer workshop in San Diego

June 2017 - September 2017 (Q3 2017):
Published Paper in MNRAS - The formation of direct collapse black holes under the influence of streaming velocities""
Appeared on national radio stations discussing Asteroid Day (June 30th).
Appeared on national radio discussing Teleportation
Appeared on national radio discussing Gravitational Wave breakthroughs

September 2017 - December 2017 (Q4 2017)
Submitted Paper to MNRAS - Fragmentation in Atomic Cooling Haloes exposed to a Lyman-Werner background.
Invited to give seminar on latest Black Hole research at the IAP in Paris. Beginning a collaboration with Marta Volonteri - world expert in black hole formation
Invited speaker at ""Titan's of the Early Universe"" meeting in Prato, Italy (November 20 - 24).
Taught module ""Numerical Methods"". 12 week course with 48 lectures.

January 2018 - April 2018
Paper accepted for publication in MNRAS - Fragmentation in Atomic Cooling Haloes exposed to a Lyman-Werner background.
Paper submitted to MNRAS - Rise of the First Supermassive Stars
Paper submitted to MNRAS - The Growth of Black Holes from Population III Remnants in the Renaissance Simulations
Appeared on National radio discussing the Lambda-CDM model of the Universe and life and death of Stephen Hawking

May 2018 - October 2018
Paper submitted to major journal - Ubiquitous massive black hole formation in rapidly growing pre-galactic gas clouds
Supervised summer student working on analysing data from the Renaissance simulations
Mentor on postdoctoral researchers application for a MSCA IF
Submitted application to Ulysses for travel funding to work with Marta Volunteri at the IAP
Submitted application to Royal Society for URF.
Organising public lectures in DCU for spaceweek. Expected attendance 250 people

The Smartstar algorithm represents a significant leap forward in modeling the collapse of black holes and super-massive stars in the first structures in our Universe. The research will allow for more detailed research into both the environment and the progenitors of black holes in the early Universe. In conjunction with another project I am working on we expect to be able to identify a pathway which appears to be a promising route to understanding the formation mechanisms for SMBH in the early Universe. The combination of these works will have a large impact on the field, particular in understanding the progenitors on the first massive black holes in the Universe.
A black hole forms in close proximity to a star-bursting protogalaxy. Published in Nature Astronomy.