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| PhD Fellowship in Studying close interactions in binary stars in the Milky Way | Closing date: 2023-01-25
Contact: La Caixa Fellowships |
| One of the key aspects for the job position will be to establish a strong knowledge about time-domain surveys, which is a very dynamic field of research that is expected to grow within the next few years. The imminent start of operations of new large time-domain surveys will offer endless opportunities to discover new transient and variable phenomena. | | ▸ more | Research Project:
The recent discovery of gravitational waves (GW) has shown that most of the detected merging compact binaries were black holes more massive than 20 solar masses. This finding has opened new questions about the progenitors and formation channels for these systems. One of the possible ways to create such compact massive binaries is through the so-called common envelope evolution, when both stars end up sharing a common gaseous layer called the common envelope. The gravitational drag of the stars inside this envelope contributes to its ejection at the expense of tightening the binary. This ejection can be observed as a bright transient source (similar to a supernova) appearing in the night sky. Eventually, the binary components can explode as supernovae, resulting in high-energy phenomena and ultimately becoming GW sources.
This project aims to use data from the Gaia ESA mission to find and characterize binary systems in our galaxy undergoing common envelope evolution, and to explore how the envelope is ejected using multi-wavelength observations of their outbursts. On the one hand, detailed follow-up campaigns will be carried out to determine the physical properties of the systems. On the other hand, comparison of the number of these systems with predictions from binary populations will provide constraints on the most relevant physics for the phases of unstable mass transfer, and envelope ejection.
The student will join the expanding research group led by Dr. Nadejda Blagorodnova, expert in astrophysical transient events, and will become a member of international collaborations associated to time-domain surveys (led by the USA and The Netherlands) and the GW LIGO-Virgo collaboration. In the Department of Quantum Physics and Astrophysics, the student will interact with experts on stellar populations with the Gaia ESA mission, and the members of the gravity and GW group in the interpretation of the results of the observations.
Job position description
One of the key aspects for the job position will be to establish a strong knowledge about time-domain surveys, which is a very dynamic field of research that is expected to grow within the next few years. The imminent start of operations of new large time-domain surveys will offer endless opportunities to discover new transient and variable phenomena.
The identification of suitable common envelope candidate systems will be achieved with the combined analysis of large datasets containing astrophysical properties of the stellar sources (provided by the Gaia ESA catalogues) and their time evolution, which will be obtained from optical and near-infrared time-domain survey catalogues. The student will carry out the analysis of these datasets using distributed parallel computing resources, and employ machine learning techniques to train the algorithms which will allow us to identify past events, and predict the ones that may occur soon. In addition, the student will also learn photometric and spectroscopic observational techniques in optical and near-infrared wavelengths, which will allow him/her to complement the catalogue data with new observations, shedding light on the physical processes involved in common envelope evolution and its role for the creation of GW sources.
To this end, the student will also broaden the knowledge on stellar binary evolution to interpret the nature and characteristics of the observed systems. Close collaboration with experts in the theory of binary evolution and common envelope will provide further training opportunities in this field. The combined expertise in observational techniques, analysis of large time-domain data, and stellar evolution will put the candidate in an excellent position to further pursue a research career.
More information:
Group leader
Dr. Nadejda Blagorodnova Mujortova ?
nblago @ fqa.ub.edu
Research product / Research group
Web site containing the bio of the PI and the description of the broader project scope
https://nblago.github.io/
Gaia ESA project. The student will be working with the latest catalogue, which contains astrophysical data on nearly two billion sources
https://sci.esa.int/web/gaia
BlackGEM time domain survey. The student will become part of the collaboration, and will have privileged access to the data
https://astro.ru.nl/blackgem/
Zwicky Transient Facility time-domain survey. The data from this survey (operating since 2018) will be used in the analysis of the time evolution and discovery of systems
https://www.ztf.caltech.edu/
https://icc.ub.edu/node/21455
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