The evolution of galaxy components and the influence of environment

Lead Research Organisation: University of Nottingham
Department Name: Sch of Physics & Astronomy

Abstract

Looking out into the universe, far beyond our nearby stars, we find a vast population of galaxies. Most of these are isolated, appearing as islands containing many stars and surrounded by mostly empty space, but they tend to group together due to the influence of gravity. Astronomers refer to various properties describing a particular region of space, including the density of galaxies, as the 'environment'. Galaxies have a wide range of properties, such as their environment, size, brightness, colour, and shape (also known as morphology). In many ways, though, they display strong similarities, and can be categorised. One endeavour of astronomy is to study the distributions of galaxy properties, determine which characteristics are important, and use these to understand how galaxies form and evolve over time. One of the most striking distinctions is between galaxies which have a disky, spiral morphology and those which appear smooth and elliptical. Disk galaxies are usually blue, while ellipticals are red. From our knowledge of nearby stars this suggests that disks contain young stars, but that ellipticals are almost entirely old. However, the division between disks and ellipticals, or blue and red galaxies, is not clear-cut. For example, there exists a significant population of red disk galaxies, especially in dense regions of the Universe. Furthermore, most disk galaxies actually contain a significant central component, called a bulge, with properties similar to a small elliptical galaxy. These different galaxy components can be partly explained by models of galaxy formation, whereby disks are formed from new gas falling onto galaxies, while spheroids (bulges and ellipticals) are created by galaxies crashing into one another. One therefore expects them to be fundamental to describing and understanding the galaxy population. However, work to date has largely ignored this and studied the overall properties of galaxies. This has generally been deemed necessary due to various difficulties in determining morphologies and separating the properties of the two components for sufficiently large numbers of galaxies. Now we have an exciting opportunity to directly access the information in the separate galaxy components, thanks to several developments. Firstly, computational tools are at a stage where they can potentially separate galaxy components quickly and reliably. Secondly, the era of citizen science has arrived: through the Galaxy Zoo project we can now harness the brain-power of large numbers of people to study the features that computers still struggle with. Finally, the latest surveys provide the quantity and quality of data required to study the internal components of galaxies and their environments in a reliable and statistically sound manner. I will analyse a wide variety of data from a number of surveys, measuring the properties of the separate components for a hundred thousand galaxies, and determining morphologies for millions of objects, both nearby and distant. Through this I aim to gain a revolutionary new understanding of the evolution of galaxies in terms of their fundamental internal structures.

Publications

10 25 50

publication icon
Bamford S (2012) Measuring SEDs for individual galaxy components in Proceedings of the International Astronomical Union

publication icon
Banfield J (2015) Radio Galaxy Zoo: host galaxies and radio morphologies derived from visual inspection in Monthly Notices of the Royal Astronomical Society

publication icon
Bauer A (2013) Galaxy And Mass Assembly (GAMA): linking star formation histories and stellar mass growth in Monthly Notices of the Royal Astronomical Society

publication icon
Casteels K (2014) Galaxy And Mass Assembly (GAMA): refining the local galaxy merger rate using morphological information in Monthly Notices of the Royal Astronomical Society

publication icon
Casteels K (2013) Galaxy Zoo: quantifying morphological indicators of galaxy interaction? in Monthly Notices of the Royal Astronomical Society

publication icon
Cheung E (2015) Galaxy Zoo: Are bars responsible for the feeding of active galactic nuclei at 0.2 < z < 1.0?? in Monthly Notices of the Royal Astronomical Society

 
Description As leader of the MegaMorph project, I have proven that using imaging at multiple wavelengths simultaneously can produce more reliable and physically meaningful measurements of galaxy structure in large surveys. The resulting measurements have been used to show that galaxies often display strong, characteristic trends in their structure as a function of wavelength, and to understand the origin of these trends. The contrasting colours of internal galaxy components are being used to understand how their developmental histories depend on mass and environment. The novel tools developed by this project have been made available to the community.

As a senior member of the Galaxy And Mass Assembly (GAMA) survey, I have helped to explore how different types of galaxies, and galaxy structural components, contribute to the overall luminosity and stellar mass of the universe. Other studies have investigated how the stellar mass in these galaxies has been built up over time. We have also produced the new standard measurements of key local galaxy distributions and relations, including the stellar mass function and size-mass relation.

In another set of studies I have contributed to, we have shown that spiral galaxies in clusters evolve into lenticular galaxies via the disruption of their internal gas reservoir, accompanied by an enhancement of the star-formation in their inner disk, at the expense of their outer disk. This has important implications for understanding the nature of the galaxy population in clusters today. I have also been involved with complementary studies of the planetary nebulae and globular cluster systems of lenticulars.

With the Galaxy Zoo team, I have helped to process our Citizen Science data into a form ready for analysis, including the development of a method for empirically correcting the biases typically found in signal-to-noise and resolution-dependent classifications. Using these data, I have demonstrated how both visual and automated measurements of morphology can be used to refine our estimate of the rate at which galaxies are merging in the local Universe. We have also studied the occurrence of specific galaxy features, e.g bars, bulges, spiral arms, versus time and environment.

In my role with the Citizen Science Alliance, I have assisted with the development of Citizen Science as a recognised and respected form of data analysis in astronomy and many other fields, and indirectly contributed to many publications and results based on the Zooniverse projects. For some projects, e.g. Moon Zoo, I have taken a more active role in helping to develop methods to aggregate markings from many, varied participants. I have also helped to investigate potential improvements to the task interface for such projects.
Exploitation Route My work is being used as the basis or support for a number of further studies.
Sectors Other

 
Description My research has mostly been used by the academic research community. However, my involvement in the Zooniverse citizen science initiative over the course of this grant has contributed to the wide-spread impact of that project. By involving millions of members of the public in real academic research activities, the Zooniverse has raised awareness of many scientific studies, as well as the general process of research. This has paved the way to an explosion in the use of citizen science to tackle novel research problems and as an engagement tool. The methods for processing citizen science data developed in Galaxy Zoo and other early astronomy-based projects have been adapted for use in projects addressing a wide range of other research areas.
First Year Of Impact 2010
Impact Types Cultural,Societal

 
Description International Collaboration Fund
Amount £1,520 (GBP)
Organisation University of Nottingham 
Sector Academic/University
Country United Kingdom
Start 07/2014 
End 12/2014
 
Description Citizen Science Alliance 
Organisation Academia Sinica
Department Institute of Astronomy and Astrophysics
Country Taiwan, Province of China 
Sector Academic/University 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Description Citizen Science Alliance 
Organisation Adler Planetarium
Country United States 
Sector Charity/Non Profit 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Description Citizen Science Alliance 
Organisation ETH Zurich
Country Switzerland 
Sector Academic/University 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Description Citizen Science Alliance 
Organisation Johns Hopkins University
Country United States 
Sector Academic/University 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Description Citizen Science Alliance 
Organisation University of Minnesota
Country United States 
Sector Academic/University 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Description Citizen Science Alliance 
Organisation University of Oxford
Country United Kingdom 
Sector Academic/University 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Description Citizen Science Alliance 
Organisation University of Portsmouth
Country United Kingdom 
Sector Academic/University 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Description Citizen Science Alliance 
Organisation Vizzuality
Country Spain 
Sector Private 
PI Contribution I was a founder of the Citizen Science Alliance, and served as Science Director on the original Executive Board, involved with the selection and development of new projects, and overseeing the collaboration's scientific output. I am now a member of the Board, with advisory and oversight responsibilities, and continue to contribute to specific projects and topics as required.
Collaborator Contribution The Citizen Science Alliance is an organization of scientists, software developers and educators who collectively develop, manage and utilise internet-based citizen science projects in order to further science itself, and the public understanding of both science and of the scientific process. These projects use the time, abilities and energies of a distributed community of citizen scientists who are our collaborators. Our principle citizen science platform is the Zooniverse (http://www.zooniverse.org)
Impact To Nov 2014, the Zooniverse projects have been directly responsible for over 75 published papers, our datasets have been used in many more. Well over a million people worldwide have contributed to Zooniverse projects, each gaining an insight into the research process and a specific field of study. For many thousands of people, participating in Zooniverse projects is a regular and significant activity.
Start Year 2009
 
Title MegaMorph 
Description We have developed and improved a set of software tools for studies of galaxy structure: GALFITM and GALAPAGOS-2. The scientific advantages of these tools have been demonstrated through a number of publications. The tools have been made publicly available, and they are now being used by a number of external groups. Much of this activity was performed on a project funded by the Qatar National Research Fund (obtained prior to this fellowship). However, I contributed some of my time under my fellowship while the QNRF project was active. Now that funding has ended, further maintenance, development and scientific exploitation of these software is being carried out as part of my fellowship. 
Type Of Technology Software 
Year Produced 2014 
Impact Several publications, with more in preparation. I am supervising a PhD student using this software and its products. Several international groups are using our software for their research. 
URL http://www.nottingham.ac.uk/astronomy/megamorph/
 
Description Citizen Science Alliance 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Science Director of the Citizen Science Alliance, which produces the "Zooniverse" collection of online citizen science projects.

These projects have engaged over a million members of the public in real research, raising scientific awareness and aspirations, while helping to produce science results which would have been difficult to achieve without large-scale public involvement.
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013,2014
URL http://www.citizensciencealliance.org
 
Description Outreach activities at UoN 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Leading aspects of various widening participation activities, including galaxy classification workshops, astronomy computer labs and observing experiences. Several events per year.

Positive feedback.
Year(s) Of Engagement Activity 2010,2011,2012,2013,2014
 
Description Primary school visit, Nottinghamshire 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Schools
Results and Impact 1) Chetwynd Primary Academy: Approximately 70 Year 6 pupils attended a talk about astronomy and working in scientific research, followed by question and answer sessions.
2) Sawley Infant School: Approximately 70 Year 1 pupils attended talks about astronomy and working in scientific research, followed by question and answer sessions.

Positive feedback.
Year(s) Of Engagement Activity 2012,2014
 
Description School visit, Nottinghamshire 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Schools
Results and Impact Talk to A-level students and staff

Positive feedback
Year(s) Of Engagement Activity 2011,2012
 
Description StarGazing Live 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Public talk at event at BBC organised event at Wollaton Hall.

Positive feedback.
Year(s) Of Engagement Activity 2011