The Quenching of Star Formation in Disc Galaxies

Lead Research Organisation: University of Portsmouth
Department Name: Institute of Cosmology and Gravitation

Abstract

Modern astronomy is the study of the physical processes which shape the universe in which we live. Over recent decades astronomers have realised that by using our knowledge of physics, we can interpret observations of the night sky to learn about the universe as a whole.

Much of this information has come from observations of the galaxies in our universe. These are the fundamental building blocks of the universe, massive collections of billions of stars which light up the underlying distribution of matter. We have a good basic picture of how the galaxies that we see (including the one we live in) started as tiny fluctuations in the density of the early universe, and over 14 billion years of cosmic history developed into the rich "Zoo" of galaxies we see today. However, as we make more and more precise observations of the universe using these galaxies as tracers, it becomes more and more important to understand all the myriad of differences we see in these galaxies. We must ask things like: Why do some have spiral structure and others not? Why do some spirals show bars and rings and others not? Why are some forming stars prodigiously and others not?

Our proposal is aimed at working with data a new survey of galaxies in the local universe, with the goal of better understanding their internal structures. This survey, called "MaNGA" will make detailed observations of the internal structure and motions of almost 10,000 galaxies - almost 100 times larger than any previous similar effort. MaNGA will take spectra ("cosmic barcode readings") in a grid across each galaxy, providing maps of the internal motions, chemical enrichment, and even the ages of the stars in the galaxy. We will use these data to test ideas about why spiral galaxies stop forming stars.

The main idea we want to test is that a galactic bar can help accelerate the ageing process of spiral galaxies, causing them to use up their fuel for star formation more quickly by increasing star formation in the central regions of the galaxy and helping to build a central bulge. We will test this with the MaNGA data on the ages of stars across the face of barred and unbarred spiral galaxies in order to determine how and if it happens, and how important it is to galaxy formation as a whole.

Planned Impact

We have a great track record of converting research into Impact via Public Engagement.

Masters is Chair of the SDSS-IV Committee on Outreach and Public Engagement and has expertise in Citizen Science methods for research (through her role as Project Scientist for Galaxy Zoo). There is interest in developing a plan for Galaxy Zoo MaNGA to involve citizen scientists in identifying patterns in the kinematic and composition maps (and correlations between them) which would contribute to the wider impact of this research. Galaxy Zoo (GZ) is among the most successful online citizen science project ever undertaken, relying on hundreds of thousands of volunteers to classify galaxy images. Since 2007, GZ has evolved into a "Zooniverse" of over 20 online projects, engaging nearly a million worldwide volunteers (from a range of ages, backgrounds and education) in scientific research. Most GZ volunteers report being motivated by a desire to contribute to real research, and many say their experience has changed their behavior e.g. more museum visits, or for under-18s, being more encouraged to study a degree or finding it helped their schoolwork. Galaxy Zoo was at the core of Portsmouth's REF Impact cases, and building on this involvement is a central part of our plans.

The ICG undertakes a broad range of outreach activities, which regularly reaches thousands of people per year (4858 in 2012-13; 6424 in 2011-12). In addition, the ICG has invested resources in a dedicated programme of "high impact" sustainable events that optimize our public engagement that draws upon our leading cosmological research above, thus ensuring our impact is topical, well-informed and inspiring. Masters was appointed the Outreach Co-ordinator of ICG in October 2011, a role which includes the supervision of the recently hired ICG/SEPnet (South East Physics Network)/Ogden Trust Outreach Officer, Dr. Jennifer Gupta. Working with Dr. Gupta, Masters has expanded the public engagement reach of the ICG, and to help all researchers working at ICG to participate in efficient and well targeted public engagement activities. These efforts continue to increase the public engagement capacity of ICG, and we are also improving our ability to track the impact of this outreach. We have been involved in several very large scale events in recent years (e.g. StargazingLIVE events in Portsmouth) and will be running an extensive public programme for NAM2014.

Masters will continue to develop her interest and expertise in public engagement and communication, especially via internet and new media routes. Continuing involvement in the Zooniverse (via proposing Galaxy Zoo: 3D will help here). Masters will disseminate the scientific method, research results, and love of astronomy in general via ongoing blog posts, public talks and school visits.

Publications

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Belfiore Francesco (2016) SDSS IV MaNGA - spatially resolved diagnostic diagrams: a proof that many galaxies are LIERs in Monthly Notices of the Royal Astronomical Society

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Belfiore Francesco (2017) SDSS-IV MaNGA - the spatially resolved transition from star formation to quiescence in Monthly Notices of the Royal Astronomical Society

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Cheung E (2015) STELLAR POPULATIONS OF BARRED QUIESCENT GALAXIES in The Astrophysical Journal

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Goddard D. (2017) SDSS-IV MaNGA: stellar population gradients as a function of galaxy environment in Monthly Notices of the Royal Astronomical Society

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Goddard D. (2016) SDSS-IV MaNGA: Spatially resolved star formation histories in galaxies as a function of galaxy mass and type in Monthly Notices of the Royal Astronomical Society

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Penny Samantha J. (2016) SDSS-IV MaNGA: faint quenched galaxies - I. Sample selection and evidence for environmental quenching in Monthly Notices of the Royal Astronomical Society

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Smethurst R (2015) Galaxy Zoo: evidence for diverse star formation histories through the green valley in Monthly Notices of the Royal Astronomical Society

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Smethurst R. J. (2016) Galaxy Zoo: evidence for rapid, recent quenching within a population of AGN host galaxies in Monthly Notices of the Royal Astronomical Society

 
Description The main outcome of the funding here (which funded my time only, no PDRA) was the successful submission of the proposal for followup HI data of MaNGA galaxies, observations for which began in Feb 2016. We have now had more than 1500 hours of GBT time for this project, however we are understaffed for the reduction of this because no PDRA was awarded for this grant, and a followup CG proposal was also not awarded a PDRA (or any investigator time). I have obtained funding via a startup funds at my new position (in the USA) to complete this project. That PDRA will start in October 2018.
Exploitation Route The HI folllowup for MaNGA will benefit potentially hundreds of publishable research outputs in the future.
Sectors Other

 
Description My research contributes to general interest and cultural impact of astronomy via inspiration for the future generations of scientists. This work has contributed to the launch of a new citizen science project in the Zooniverse. Citizen science has been demonstrated to inspire member of the public to have a greater interest in science, and to learn more about the scientific method.
First Year Of Impact 2016
Sector Education,Other
Impact Types Cultural

 
Description Startup Funds from Haverford College, USA
Amount $203,000 (USD)
Organisation Haverford College 
Start 01/2018 
End 01/2022
 
Description Galaxy Zoo 
Organisation GlaxoSmithKline (GSK)
Country Global 
Sector Private 
PI Contribution I am the lead project scientist for Galaxy Zoo.
Collaborator Contribution Galaxy Zoo runs a website in which we collect crowdsourced morphologies of galaxies which I use in many of my outputs.
Impact Publications resulting from this collaboration have "Galaxy Zoo" in the title. The cultural impact of involving hundreds of thousands of members of the public in our research is also large.
Start Year 2007
 
Description Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) 
Organisation Sloan Digital Sky Survey (SDSS-III)
Country United States 
Sector Academic/University 
PI Contribution Survey operations, specifically co-ordination of follow-up plans.
Collaborator Contribution Survey operations, collecting data, collaborations meetings and science collaboration.
Impact Several of the listed outcomes are linked to this collaboration.
Start Year 2014
 
Description Astrodome sessions (at schools visits or schools events). 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Participated in one astrodome visit to a local primary (in April 2015), and one event at our Stargazing for School activity (Jan 2016), at which a total of ~120 school children saw dome shows.
Year(s) Of Engagement Activity 2015,2016
 
Description Galaxy Zoo: 3D 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Launch of citizen science project "Galaxy Zoo: 3D"
Year(s) Of Engagement Activity 2017
URL https://www.zooniverse.org/projects/klmasters/galaxy-zoo-3d
 
Description Public Talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Public talks given in Hampshire (May 2015), York (June 2015), Brighton (October 2015) and Dublin (November 2015) to audiences of typically 70-200.
Year(s) Of Engagement Activity 2015
 
Description Radio4 Today Show 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Spot on BBC Radio 4 Today Show to talk about black holes. Lots of positive comments from colleagues, friends and family who listened suggest the interview came across well. Resulted in interest from a publisher in a possible public science book.
Year(s) Of Engagement Activity 2016
 
Description SDSS Teacher Plate Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Our SDSS Teacher Workshop saw teachers attend from all over the South East, taking back with them to the classroom knowledge of how to use SDSS data for learning experiences in science, maths and engineering, as well as taking with them an SDSS plate for use in teaching. The reach of this event is therefore significantly larger than the attendees on the day, most of whom stated how useful the workshop was and their intention to try to make use of it in teaching.
Year(s) Of Engagement Activity 2016
 
Description Stargazing LIVE at Portsmouth Historic Dockyard 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Our annual Stargazing LIVE event at the Portsmouth Historic Dockyard is a chance to engage with the local public about our research.
Year(s) Of Engagement Activity 2016
 
Description UP for IT Juniors Mini Lectures 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Mini-lecture: The Scale of the Universe, given as part of the Up for IT Juniors day of events, bringing local primary students onto campus. Students report increased confidence and desire to attend University following their visits.
Year(s) Of Engagement Activity 2015
 
Description Work Experience Week 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Out Year 10 work experience week saw 6 young people from the local area spend a week in the department learning about what it means to be a research scientist. Attendees reported increased confidence in pursuing STEM subjects at University.
Year(s) Of Engagement Activity 2015