The Quenching of Star Formation in Disc Galaxies

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.

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.