Nicolaus Copernicus Astronomical Center invites applications for Astronomy and Astrophysics PhD studies.

 

The Nicolaus Copernicus Astronomical Center, a leading institute of the GeoPlanet Doctoral School, offers the opportunity to carry out graduate studies leading to a PhD degree in Astronomy and Astrophysics. The present, supplementary call, concerns three topics in the field of stellar astrophysics.   A separate recruitment procedure will be conducted for each topic. Candidates can send applications for more than one topic.

The program of the studies is related to subjects pursued at the Copernicus Center including observational and theoretical astrophysics as well as cosmology. Our senior scientists participate in the H.E.S.S., CTA, and VIRGO/LIGO projects and are involved in instrumental projects concerning the astronomical satellites INTEGRAL, SPICA and ATHENA. The Copernicus Center represents the Polish astronomical community in the SALT consortium which operates an 11-m optical telescope in South Africa. The Center's scientists are leading participants in the Polish scientific satellite project, BRITE, dedicated to precise stellar brightness measurements, and in the project ARAUCARIA, dedicated to the calibration of the cosmological distance scale. They also operate SOLARIS – a network of southern hemisphere small robotic telescopes committed to stellar astronomy and the search for exoplanets.

Studies last 4 years. Students starting this year begin their course on October 1, 2019. During the 4 year period students are required to take specific courses, lecture and seminar series, including interdisciplinary lectures, as well as prepare the doctoral thesis. All seminars and lectures are in English. Students take their courses in Warsaw or in Toruń according to the location of employment of their supervisor.

An attachment to this announcement contains an information about prospective supervisors and description of the proposed three PhD topics. Candidates should contact their potential supervisors to obtain more details on the proposals. The regulations of the doctoral school, including the program of Studies, are posted on the Copernicus Center web page https://www.camk.edu.pl/en/phd/recruitment/.

Candidates should provide their complete application documents including:

1. The application for admission to the doctoral school, according to the template available on the  NCAC  website with GDPR statement;
2. A copy of their Master/University degree diploma. In case this is not yet available, it must be provided before the candidate is admitted to the school;
3. A transcript of grades (Bachelor and Master Courses);
4. A Curriculum Vitae including  an education and employment record, list of publications, information on involvement in scientific activities – membership in scientific groups/societies, participation in scientific conferences, internships and trainings, awards and distinctions;
5. A letter of motivation containing a short description of the cadidate’s interests and scientific achievements,  and justification of the intention to undertake education at the Doctoral School;
6. English language certificate(s), if available;

In addition, at least one recommendation letter should be sent directly to: phdstudies@camk.edu.pl. In the case that the Master’s thesis is ready, it can be attached to the application. Applications should be addressed to the Center’s Director and can be sent either by mail or by e-mail to phdstudies@camk.edu.pl, by August 31st, 2019.


The Recruitment Board will select candidates for the interview, which will take place on September 5th-20th, 2019 (10 am – 3 pm). Decisions about admission will be made by the end of September, 2019 and all the candidates will be notified by e-mail. For additional information contact the coordinator of the doctoral school, Dr. Radosław Smolec (smolec@camk.edu.pl) or the Center’s secretary office (Ms. Katarzyna Morawska, kasia@camk.edu.pl).

(Download as pdf file)

 

Warsaw, July 29th, 2019

prof. dr hab. Piotr Życki

NCAC Director    

 

 

Proposed subjects of PhD theses

 

Subject: Stellar astronomy and astrophysics, ground based eclipse timing and analysis of satellite-borne observations of detached eclipsing binaries

 

Advisor: Prof. Maciej Konacki (maciej@ncac.torun.pl)

Co-advisor: Dr Krzysztof Hełminiak (xysiek@ncac.torun.pl)

 

The aim of the project (1) is to characterize with high precision eclipsing binary stars and search for circumbinary companions (stellar and planetary) thanks to the timing measurements of their eclipses. Determined parameters of the components of the binaries will be combined with the distances from the Gaia mission and used to test the models of stellar structure and evolution. Both parts of the project will be based on a vast database of photometric and spectroscopic measurements from the "Solaris" project. These database contains over 2 million frames (thousands of nights).

The aim of the project (2) is to obtain high-precision (<1%) fundamental stellar parameters for components of selected detached eclipsing binaries. This will be done by producing models of these binaries on the basis of quality spectroscopic material and very high precision, satellite-based photometry from missions such as Kepler/K2, TESS, Gaia, and others. The models will be made for about 150-200 systems (depending on the availability of data). The results will be a base for further analysis, aimed for obtaining ages, chemical composition or distances to the systems. Results will be published in refereed journals (ApJ, MNRAS, A&A) and included in the newly created catalogue of eclipsing systems TSEBOOLA.

These tasks can be enhanced with new observing campaigns. The "Solaris" network consists of 4 robotic telescopes (0.5-m, 2 in South Africa, one in Argentina and one in Australia) with Johnson-Cousins (UBVRI) and Sloan (u'g'r'i'z') filter sets. Additionally, one of the telescopes in South Africa is equipped with a medium resolution (R = 20 000), high throughput echelle spectrograph suitable for stellar astronomy up to about 11 mag.

 

 

Subject: The origins of the r-process heavy elements

Advisor: Dr hab. Rodolfo Smiljanic (rsmiljanic@camk.edu.pl)

 

The rapid neutron-capture process is responsible (or very important) for the creation of about half of the elements heavier than iron in the periodic table. However, the astrophysical sites of r-process nucleosynthesis are still debated. Recently, signatures of the r-process nucleosynthesis were detected in the ejecta of a kilonova, following the merger of two neutron stars where a gravitational wave signal was detected (GW170817). Nevertheless, observational evidence seems to show that neutron-star mergers can not be the only neither the dominant site of r-process nucleosynthesis.

This PhD project aims to contribute to the quest of understanding the origins of the r-process elements by performing a detailed observational investigation of r-process elements in old metal-poor stars. The goal is to determine abundances for all possible heavy elements (e.g., Mo, Ru, Pd, La, Ce, Pr, Sm, Eu, Gd, among others) with lines in the near-UV region (300-400 nm) of the stellar spectrum. Gaia kinematic data will be used to investigate the origin of the stars, separating them into those likely formed in situ in the Milky Way and those accreted from external systems. This will result in a global overview of the r-process nucleosynthesis characteristics, highlighting differences related to the distinct environments where the metal-poor stars were formed.

Previous experience in the analysis of medium- and high-resolution stellar spectra is desirable, but not mandatory for the candidates. This PhD project will be financed within the project “Near-UV stellar spectroscopy: uncovering the past and building the future” funded by the Polish National Science Center. The work developed in this project can be potentially important for the development of a new near-UV spectrograph for the ESO VLT.

 

 

Subject: Classical Cepheids as testbeds for stellar pulsation and evolution theories

Advisor: Dr hab. Radosław Smolec (smolec@camk.edu.pl)

 

Classical Cepheids are one of the most important tools of modern astrophysics and cosmology. As excellent standard candles and tracers of young stellar populations they allow to study the structure and evolution of the Milky Way and of the Magellanic Clouds. Still, there are many puzzles concerning evolution and pulsation of Cepheids. The student’s research will focus on one of the following topics.

1. Constraints on stellar evolution theory from Cepheids in eclipsing binary systems.  Masses of classical Cepheids predicted by stellar evolution theory are 10-20 per cent too high as compared to determinations resulting from pulsation theory, or resulting from dynamical mass determinations for Cepheids in eclipsing binary systems. Cepheids in eclipsing binary systems are excellent tools to address this problem. The student will conduct detailed evolutionary and pulsation modeling of classical Cepheids, members of eclipsing binary systems, with emphasis on the role played by processes such as element mixing, mass loss and rotation, and their mutual interaction. The student will investigate current limitations of the stellar evolution and pulsation theories and will calibrate the parameters entering the model calculations. Modeling will be done with software instruments available in MESA: stellar evolution and stellar pulsation codes.
2. Investigation of pulsation period changes in classical pulsators. As star evolves, its pulsation period changes. Evolution theory predicts these changes should be slow and monotonic. It turns out that in many stars the observed period changes are much more complex: they are irregular and occur on a much shorter time scale. The mechanism behind these non-evolutionary changes is unknown. The student will conduct a comprehensive investigation of pulsation period changes in classical pulsators using data of the OGLE project and archival data. The goal is to describe the fast changes quantitatively for the first time. This is a necessary step to disentangle  slow changes due to evolution from fast and irregular changes. This research will also help to understand the mechanism behind the non-evolutionary changes.

Student will also take part in Cepheid observations in the Cerro Armazones Observatory in Chile. Good knowledge of programming languages will be an asset. This investigation is part of the SONATA BIS research project funded by the National Science Center.