Dissecting galaxies at the cosmic dawn

Lead Research Organisation: Liverpool John Moores University
Department Name: Astrophysics Research Institute

Abstract

Contemplating our origins is a key part of what makes us human, and has provoked ideas and stories in every civilisation. My research is similarly motivated by this curiosity. I am driven by questions such as: How were stars and galaxies first formed after the creation of the Universe in the Big Bang? How did they differ from those we see around us in the local Universe? When were the elements necessary for life, such as oxygen, carbon and nitrogen, first created? The formation of the first stars and their assembly into the first galaxies is now a frontier focus of modern physics, and the subject of intensifying research activity.

Owing to the finite speed of light, we see galaxies farther back in time by observing more distant examples. The scrutiny and refinement of models of structure formation in the early Universe therefore requires direct observation of the most-distant galaxies. The installation in 2009 of new instrumentation aboard the Hubble Space Telescope (HST) enabled it to detect starlight that travelled across the cosmos for 13.4 billion years, emitted from galaxies seen only 400 million years after the Big Bang. These remarkable observations proved that galaxies, and the elements needed for life, were present mere moments into cosmic history.

Hubble's forthcoming successor, the James Webb Space Telescope (JWST), aims to discover the forebears of these systems and characterise the physical processes governing the growth of the very first generation of galaxies. Due to launch in 2021, JWST's instruments will reveal galaxies seen 100 million years after the Big Bang. Over the next five years I will exploit the world's premier ground-based telescopes, and JWST, to answer fundamental questions such as: When did the first stars and galaxies form? How rapidly did the first galaxies evolve, and which physical processes regulated their growth? Which galaxies were responsible for ionising the intergalactic neutral hydrogen that pervaded the early Universe? Did the stars within galaxies dominate this process, or was it driven by the first population of black holes?

My analyses will deliver measurements of the fundamental diagnostic quantities that describe the formation and evolution of the first galaxies. They will thus enable refinement of galaxy evolution models in a regime that is at present wholly unconstrained by observations. Such measurements are the crucial ingredient needed to foster the next major development in our understanding of the structures that first illuminated the cosmos.

Publications

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Hainline K (2020) Simulating JWST/NIRCam Color Selection of High-redshift Galaxies in The Astrophysical Journal

 
Title On the origin of [CII] in the Epoch of Reionization 
Description ALMA program 2018.1.01551.S. This program is a pilot to understand the interstellar medium of galaxies in the first billion years of cosmic time, searching for the presence of the diffuse ionised medium. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact A paper is in preparation, led by my PhD student Joris Witstok. 
URL https://almascience.eso.org/asax/
 
Title Resolving the kinematic structure of a [CII] emitter 800 million years after the Big Bang 
Description ALMA data-set 2017.1.00604.S. The deepest ever look at the dust and cool gas in a galaxy in the first billion years of cosmic time. One of the key aims is to confirm the nature of disk kinematics in this early system. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Preliminary analysis has been used to successfully obtain larger data samples. 
URL https://almascience.eso.org/asax/
 
Title The ISM conditions of UV-selected galaxies in the Epoch of Reionization 
Description ALMA program 2018.1.00429.S. This program aims to uncover the physical properties of star-forming regions in two pilot sources in the first billion years of cosmic time. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact The preliminary pilot results were used to successfully obtain a larger data-sample. 
URL https://almascience.eso.org/asax/
 
Title Using [OIII] to reveal the ISM conditions of UV-selected galaxies in the Epoch of Reionization 
Description ALMA program 2019.1.01524.S. This program aims to expand the sample of sources for which we can study the physical properties of the star-forming regions in galaxies in the first billion years of cosmic time. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact Data collection is not yet completed. A paper is in preparation on 
URL https://almascience.eso.org/asax/
 
Description Local analogs of z>6 galaxies 
Organisation Space Telescope Science Institute
Country United States 
Sector Academic/University 
PI Contribution I have co-written all telescope proposals for this project, resulting in a 10 orbit Hubble Space Telescope program (in-kind $25,000), complemented by 4 hours on the Gemini telescope (in-kind $15,000).
Collaborator Contribution Nimisha Kumari, a research fellow at the Space Telescope Science Institute, who is my co-PI for these proposals, has analysed archival data available on local analog of the distant galaxies I observe with ALMA.
Impact A paper on the Hubble Space Telescope data is being prepared by Nimisha Kumari.
Start Year 2020
 
Description REBELS: Reionization Era Bright Emission Line Survey 
Organisation Hiroshima University
Country Japan 
Sector Academic/University 
PI Contribution I am a leading member of the international REBELS team, sitting on its management board and responsible for data-processing.
Collaborator Contribution I have listed my collaborators on the management board and collaborators that have unique telescope data access though their country and/or University.
Impact We are collecting the largest data-set of galaxies in the first billion years of cosmic time with the ALMA telescope. Data collection is 80% completed
Start Year 2019
 
Description REBELS: Reionization Era Bright Emission Line Survey 
Organisation Leiden University
Department Leiden Observatory
Country Netherlands 
Sector Academic/University 
PI Contribution I am a leading member of the international REBELS team, sitting on its management board and responsible for data-processing.
Collaborator Contribution I have listed my collaborators on the management board and collaborators that have unique telescope data access though their country and/or University.
Impact We are collecting the largest data-set of galaxies in the first billion years of cosmic time with the ALMA telescope. Data collection is 80% completed
Start Year 2019
 
Description REBELS: Reionization Era Bright Emission Line Survey 
Organisation Swinburne University of Technology
Country Australia 
Sector Academic/University 
PI Contribution I am a leading member of the international REBELS team, sitting on its management board and responsible for data-processing.
Collaborator Contribution I have listed my collaborators on the management board and collaborators that have unique telescope data access though their country and/or University.
Impact We are collecting the largest data-set of galaxies in the first billion years of cosmic time with the ALMA telescope. Data collection is 80% completed
Start Year 2019
 
Description REBELS: Reionization Era Bright Emission Line Survey 
Organisation University of Arizona
Country United States 
Sector Academic/University 
PI Contribution I am a leading member of the international REBELS team, sitting on its management board and responsible for data-processing.
Collaborator Contribution I have listed my collaborators on the management board and collaborators that have unique telescope data access though their country and/or University.
Impact We are collecting the largest data-set of galaxies in the first billion years of cosmic time with the ALMA telescope. Data collection is 80% completed
Start Year 2019
 
Description REBELS: Reionization Era Bright Emission Line Survey 
Organisation University of California, Los Angeles (UCLA)
Country United States 
Sector Academic/University 
PI Contribution I am a leading member of the international REBELS team, sitting on its management board and responsible for data-processing.
Collaborator Contribution I have listed my collaborators on the management board and collaborators that have unique telescope data access though their country and/or University.
Impact We are collecting the largest data-set of galaxies in the first billion years of cosmic time with the ALMA telescope. Data collection is 80% completed
Start Year 2019
 
Description REBELS: Reionization Era Bright Emission Line Survey 
Organisation University of Chile
Country Chile 
Sector Academic/University 
PI Contribution I am a leading member of the international REBELS team, sitting on its management board and responsible for data-processing.
Collaborator Contribution I have listed my collaborators on the management board and collaborators that have unique telescope data access though their country and/or University.
Impact We are collecting the largest data-set of galaxies in the first billion years of cosmic time with the ALMA telescope. Data collection is 80% completed
Start Year 2019
 
Description REBELS: Reionization Era Bright Emission Line Survey 
Organisation University of Geneva
Department Geneva Observatory
Country Switzerland 
Sector Academic/University 
PI Contribution I am a leading member of the international REBELS team, sitting on its management board and responsible for data-processing.
Collaborator Contribution I have listed my collaborators on the management board and collaborators that have unique telescope data access though their country and/or University.
Impact We are collecting the largest data-set of galaxies in the first billion years of cosmic time with the ALMA telescope. Data collection is 80% completed
Start Year 2019
 
Description Guest lecturer University of Amsterdam 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact I was invited to deliver a lecture, including student discussion, on the formation of the first stars and galaxies for an interdisciplinary undergraduate module on the topic of 'Big History' at the University of Amsterdam.
Year(s) Of Engagement Activity 2021
URL https://www.uva.nl/en/programmes/open-programmes-iis/big-history-en/big-history-kopie.html?cb
 
Description Lecturer International Summer School 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I was invited as a lecturer for a First Light Summer School in Sao Paulo, Brazil, attended by 100 undergraduate and graduate students in Physics in Astronomy in 2020. Lectures sparked discussion afterwards. By demand, a virtual return of the school was organised in 2021.
Year(s) Of Engagement Activity 2021
URL http://www.firstlight.iag.usp.br/