Single and binary star population models
Lead Research Organisation:
University of Surrey
Department Name: Physics
Abstract
The 21st century is where big data meets astronomy. Grand surveys, like the European Space Agency's Gaia are already
providing us with unprecedented volumes of data on every type of star in our Galaxy and beyond. Others, like SDSS and
Galah, give chemical information on these stars. Others still, such as Pan-STARRS, detect transient phenomena such as
supernovae and stellar merging. Given all this information, how do we best link it to the modelling of the sources of most of
the light in the Universe: the stars themselves? There are many problems in stellar evolution, in particular relating to binary
stars and their key role in type Ia supernovae, stellar merging and as gravitational wave sources, which will benefit hugely
from big survey data. This project aims to develop the tools to do this by employing state-of-the-art statistical techniques to
compare single and binary star population models to observations of populations of stars, in a quantifiable, reliable and fast
way. It will use publicly available data from Gaia and other bi g surveys to pin down long-debated uncertainties in the
astrophysical models that go into our models of stars, both single and binary, as constructed at the University of Surrey.
The aim is to provide the tools developed for the astronomical community, thus helping to enhance both Surrey's
international reputation and that of the student. This is a huge astrostatistical problem which needs addressing urgently!
providing us with unprecedented volumes of data on every type of star in our Galaxy and beyond. Others, like SDSS and
Galah, give chemical information on these stars. Others still, such as Pan-STARRS, detect transient phenomena such as
supernovae and stellar merging. Given all this information, how do we best link it to the modelling of the sources of most of
the light in the Universe: the stars themselves? There are many problems in stellar evolution, in particular relating to binary
stars and their key role in type Ia supernovae, stellar merging and as gravitational wave sources, which will benefit hugely
from big survey data. This project aims to develop the tools to do this by employing state-of-the-art statistical techniques to
compare single and binary star population models to observations of populations of stars, in a quantifiable, reliable and fast
way. It will use publicly available data from Gaia and other bi g surveys to pin down long-debated uncertainties in the
astrophysical models that go into our models of stars, both single and binary, as constructed at the University of Surrey.
The aim is to provide the tools developed for the astronomical community, thus helping to enhance both Surrey's
international reputation and that of the student. This is a huge astrostatistical problem which needs addressing urgently!
Organisations
People |
ORCID iD |
| Robert George Izzard (Primary Supervisor) | |
| David Hendriks (Student) |
| Description | For now it is clear that binary star systems are able to lose an additional amount of angular momentum during their evolution/interaction, which has not been taken into account by previous studies. This will have an impact on further studies concerning evolution of binary stars. |
| Exploitation Route | The models and results that I am creating will give insight to other researchers that model either star systems or study galactic or cluster evolution. |
| Sectors | Other |
| Title | Action-Angle Monte-Carlo sampling |
| Description | Action-Angle Monte-Carlo sampling is a new method for model inference and probability distribution sampling that combines Hamiltonian Monte-Carlo with the new techniques of Normalising Flows and Action-Angle transformations. These transformations will allow the sampling of complex (multi-modal) probability distributions more efficiently than the popular alternative NUTS. Our new sampling technique enables faster sampling. Our use-case is related to the inference of galaxy evolution models, but can be generally applied. We are currently in the final stage of development, and we are starting the write-up of the paper. We have not yet published the code, but we intend to make the code base public as soon as we submit the paper. |
| Type Of Technology | Webtool/Application |
| Year Produced | 2023 |
| Impact | This software will allow for faster sampling of complex distributions than the popular alternatives. This is a generally useful tool in any uncertainty estimation and model inference scenario. The impact is potentially large. |
| URL | https://gitlab.com/dhendriks/project_hmc |
| Title | Astrotalks repository |
| Description | This website provides a curated repository of online lectures, seminar talks and colloquia on the topic of astrophyics. |
| Type Of Technology | Webtool/Application |
| Year Produced | 2023 |
| Open Source License? | Yes |
| Impact | With this easy-to-navigate website it is trivial for public users to browse the extensive collection of online video material on topics in astrophysics. Bringing knowledge to the people, for free. |
| URL | https://dhendriks.gitlab.io/astrotalks/ |
| Title | Python package for the binary_c software |
| Description | I developed a Python package for the binary_c software that my supervisor has created. This allows for an easy and flexible use of the core program binary_c, through a python interface which includes many utility functions and tools. We expanded the functionality and reliability of this software extensively over the past two years. Many new features are available, and the codebase has matured. The code and functionality is used in several (past) projects and will be used by more people soon. We are currently in the final stage of submission to the Journal of Open Source Software (JOSS, https://joss.theoj.org/papers/7c43806e6d1f82c2945e12ae500f03b2#) |
| Type Of Technology | Webtool/Application |
| Year Produced | 2023 |
| Open Source License? | Yes |
| Impact | Ease of use by researchers since Python is a very well known language. With clear documentation and many examples, it is our intention to make it easy for non-experts to use. |
| URL | https://pypi.org/project/binarycpython/ |
| Description | Attendance of Winterschool |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Attendance and participation in the Tenerife Winter School Universe In a Box. Discussed many research topics with fellow post-graduate students and learned new tools and skills during the workshop. |
| Year(s) Of Engagement Activity | 2019 |
| URL | http://research.iac.es/winterschool/2019/ |
| Description | Outreach activities at the university |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Schools |
| Results and Impact | Over the course of my PhD I frequently helped with open days and public stargazing evenings, which on average were attended by 20-40 people per event. This sparked much interest to the audience and most probably encouraged new students to come and study physics |
| Year(s) Of Engagement Activity | 2018,2019,2020 |
| Description | PIMMS 2021 workshop |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | This was a workshop about astroseismology/pulsations for intermediate and massive stars. The activity was held online and around 40 attendants were there each day. Many people presented novel work, and each day there were interesting discussions. No doubt several good new collaborations were made from this. I helped organize this workshop |
| Year(s) Of Engagement Activity | 2021 |
| URL | https://www.ias.surrey.ac.uk/event/pulsations-mass-stars/ |
| Description | Poster on PPISNe research |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Presented a poster on my research on Pulsational Pair-Instability supernovae during the EAS 2022. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://k-poster.kuoni-congress.info/eas2022/poster/7c4ae629-b561-4a80-9d5c-feeb8db2285f |
| Description | Presentation on research |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Undergraduate students |
| Results and Impact | Presentation on my research on gravitational wave sources, and the impact of Pulsational Pair-instability systems. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://nsaweb.nl/blog/albertx/ |
| Description | Space-week Guildford |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | Gave presentations on astrophysics related topics during the Guildford Space week |
| Year(s) Of Engagement Activity | 2018,2020,2021,2022 |
| URL | https://www.iop.org/events/world-space-week-2022 |
| Description | Student supervisions |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Undergraduate students |
| Results and Impact | Over the course of my PhD I helped my supervisor with the supervision of undergraduate students for several projects. This was a very good experience for the students as well as for me, and everybody learned a lot from these projects. |
| Year(s) Of Engagement Activity | 2018,2019,2020,2021 |
| Description | binary_c workshop 2019 |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Around 20 other researchers attended this workshop, either digitally or physically. We probably reached even more people by through the recordings we uploaded on youtube. The workshop was a great moment for many people to learn more about the software we use, and how to create new science with it, and from it several good discussions arose and collaborations were formed. I was helped organise the workshop |
| Year(s) Of Engagement Activity | 2019 |
| URL | http://personal.ph.surrey.ac.uk/~ri0005/binary_c-workshop.html |