General Recruitment 2020/2021,Nicolaus Copernicus Astronomical Center, Warsaw

Creation date: 17.01.2020, Archive date: 17.01.2020

General Recruitment 2020/2021

Nicolaus Copernicus Astronomical Center

invites applications for astronomy and astrophysics PhD studies and related fellowship competitions

The Nicolaus Copernicus Astronomical Center (CAMK PAN), 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 PhD studies are 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 and begin on October 1, 2020. During the 4 year period, students are required to take specific courses, lectures (including interdisciplinary lectures) and participate in seminars, as well as prepare the doctoral thesis. All seminars and lectures are in English. The regulations of the doctoral school, including the program of the Studies, are posted on the Copernicus Center web page https://www.camk.edu.pl/en/phd/.

Students are based and take their courses in Warsaw or in Toruń according to the location of their supervisor. Students based in Warsaw may apply for accommodation in the hotel run by our Center.

An attachment to this announcement contains an information about the proposed research topics and supervisors. Candidates can apply for more than one topic, but should clearly indicate the preferred one. Before applying, candidates should contact their potential supervisors to obtain more details on the proposals.

Students in the doctoral school receive a scholarship for the period of 4 years. The minimum amount of scholarship as set in the Law on higher education and science is 2370 PLN/month, gross, before the mid-term evaluation (years 1–2) and 3650 PLN/month, gross, after the positive mid-term evaluation (years 3–4). For several projects related to research grants funded by the Polish National Science Center (NCN) or by the Foundation for Polish Science (FNP) a higher scholarship is available. Increased scholarship paid by the Center is available for other topics. Details are given in the description of each project. For projects with NCN/FNP funding recruitment for the doctoral school is accompanied by a scholarship competition, according to the specific rules of the project. Separate ranking lists will be considered for these projects.

Candidates should provide their complete application documents including:

The application for admission to the doctoral school, according to the template available on the CAMK PAN website together with GDPR statement (https://www.camk.edu.pl/en/phd/recruitment/);
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;
A transcript of grades (Bachelor and Master Courses);
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 training, awards and distinctions;
A letter of motivation containing a short description of the candidate's interests and scientific achievements, and justification of the intention to undertake education at the Doctoral School;
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.

For topics accompanied by a scholarship competition, additional GDPR statement, following the template available at https://www.camk.edu.pl/en/about/ochrona-danych-osobowych/ (“NCN GDPR Documents”) should be signed and attached to the application.

All documents should be in the PDF format, including scans. Applications should be addressed to the Center’s Director and should be sent by e-mail to phdstudies@camk.edu.pl, by March 3rd, 2020.

The Recruitment Board will select candidates for the interview, which will take place in March, 16 – 27th, 2020 (10 am – 3 pm). Decisions about admission will be made at the beginning of April, 2020 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).

Warsaw, January 17th, 2020

Attachment: Proposed topics of PhD theses:

Subject: Position in LIGO/Virgo and Binary Evolution/Globular Cluster Science

Supervisor: Prof. Krzysztof Belczyński (contact: belczynski@camk.edu.pl)

We open a search for a graduate student to take part in study of double compact object merger populations formed in isolated binary evolution and in globular cluster environment. This project is set to identify the origin of LIGO/Virgo sources of gravitational waves. Candidates with fluent English (speaking and writing), at least one published paper, knowledge of stellar and binary evolution, and prior experience of working with population synthesis codes and Monte Carlo globular cluster codes are favored. A selected student will join the astrophysics group of Chris Belczynski and will work in a vibrant and international environment of Polish Academy of Science Center for Astrophysics (Nicolaus Copernicus Astronomical Center) at Warsaw, Poland. The winning student will be expected to travel internationally (USA, Japan, China, Australia, Europe) to carry her/his project in collaboration with world-class experts. Additional funding will be available for conferences and schools. We seek the best and the most independent students to take part in our ground-breaking project. The selection will be fully based on the quality of an application. All minorities are encouraged to apply.

Funding: This offer is accompanied by a scholarship competition from the National Science Center MAESTRO project, number 2018/30/A/ST9/00050, entitled "Astrophysics of gravitational waves" led by prof. Krzysztof Belczyński. Scholarship in the total amount of 4500 PLN/month, gross, is available for 4 years.

Location: Warsaw

Subject: Position in Planetary Science

Supervisor: Prof. Krzysztof Belczyński (contact: belczynski@camk.edu.pl)

We open a search for a graduate student to take part in study of extra-solar system planets and for the ongoing quest to identify planets that can potentially host life. This is an interdisciplinary effort that connects astrophysics, biology, climatology, geophysics and physics of planet formation. The successful candidate is to collect the existing observational data on extra-solar planets, understand and adopt current models of planet formation, and employ current models of life development to synthesize all into her/his population synthesis model of planets (numbers, configurations, habitability, life development) in our Galaxy. This model is to be used to assess the chances of life formation throughout the Milky Way and to identify the closest planets that may bear life. This project will require a very independent personality that can navigate various research fields and who can overcome the lack of data and models and understanding to create tools to attack one of the most important issue in science. Candidates with fluent English (speaking and writing), at least one published paper, outstanding knowledge of astrophysics, biology, geophysics, chemistry and physics are favored. A selected student will join the astrophysics group of Chris Belczynski and will work in a vibrant and international environment of Polish Academy of Science Center for Astrophysics (Nicolaus Copernicus Astronomical Center) at Warsaw, Poland. The selection will be fully based on the quality of an application. All minorities are encouraged to apply.

Funding: Additional scholarship paid by the Institute, to amount to total of 4500 PLN/month, gross, during the first year. For the following years, the amount of the scholarship will depend on the availability of funding.

Location: Warsaw

Subject: Automatic methods for quantum neural networks design

Supervisors: Dr hab. Piotr Gawron (CAMK PAN, contact: gawron@camk.edu.pl), Dr hab. Michał Bejger (contact: bejger@camk.edu.pl)

Development of the Near Intermediate Scale Quantum computers and many successes of machine learning led to emergence of a new field of quantum machine learning. Recently various concepts of quantum neural networks were proposed, one idea is to employ shallow variational quantum circuits to perform supervised classification. It was already shown that simple classification tasks can be efficiently performed using such shallow quantum circuits. Unfortunately little is known about architecture design of such quantum neural networks, how to mix quantum and classical nodes in such networks, and how to adapt neural networks architectures to the existing quantum computers topologies.

A successful student will work on a selection of the above problems. The goal of this work is to bring quantum neural networks closer to applications. This goal can be reached by applying various analytical and simulation methods. In particular it is interesting to study how reinforcement learning could be applied for designing quantum neural networks architectures. Quantum noise and methods of dealing with it have to be taken into account and studied.

Usability of the implementations obtained during the theoretical part of the study will be investigated on the data collected by the currently-operating gravitational-wave detectors, LIGO and Virgo, as well simulated data of planned future detectors, such as the Einstein Telescope. Specifically, the methods of quantum machine learning will be applied to automatize and speed-up the tasks of detection, classification and parameter estimation of astrophysical signals and detector artifacts in the incoming era of routine gravitational-wave detections.

A potential candidate should have background in computer science, physics or mathematics. She or he should be able to perform analytical calculations, numerical simulations and write programs using machine learning libraries.

Funding: This offer is accompanied by a scholarship competition from the Foundation for Polish Science AstroCeNT project. Scholarship in the total amount of 4500 PLN/month, gross, is available for 33 months.

Location: Warsaw

Subject: Numerical simulations of star cluster evolution – “observational” analysis of the database of numerical simulations

Supervisor: Dr hab. Mirosław Giersz (contact: mig@camk.edu.pl)

Globular clusters are among the oldest and most structurally simple objects in the Milky Way. Unfortunately, their simple structure does not mean that they can be easily numerically modeled. Close, mutual, gravitational interactions between stars, star collisions, stellar and binary evolution, the galactic tidal field are only a fraction of physical processes which have to be considered in the numerical simulations of cluster evolution. The dynamical MOCCA code is developed in the Nicolaus Copernicus Astronomical Center and is one of the world’s best codes for star cluster evolution. The code is able to simulate evolution of real star cluster on levels of precision and detail comparable to N-body codes, but much faster.
Tasks to be performed:
1. Work on the development of the Monte Carlo code in the direction of implementation of tidal interactions between stars and also between globular clusters and the host galaxy.
2. Further development of the special tools needed for fast and nearly automatic conducting of comparisons between results of simulations and observational data with use of the database of simulation models.
3. Use of the observational techniques to perform numerical data simulation analysis in order to determine the influence of multiple stellar populations, binaries, dense environment, observational errors and very bright objects on the global star cluster parameters determined from observations and parameters of populations of “exotic” objects observed in star clusters (such as: blue stragglers, cataclysmic variables, millisecond pulsars, X-ray binaries, Supernovae Ia, black holes, intermediate mass black holes…).

Location: Warsaw

Subject: Precision asteroseismology of massive stars with the TESS mission

Supervisor: Prof. Gerald Handler (contact: gerald@camk.edu.pl)

TESS is the acronym for Transiting Exoplanet Survey Satellite, a NASA space mission launched in April 2018. TESS performs an all-sky survey of bright stars for transiting exoplanets, but it also has an asteroseismology program to study the interiors of stars by using their oscillations as seismic waves. In this framework, high-precision measurements (of a quality compared to that of the Kepler mission, but for stars some five magnitudes brighter) with rapid time sampling will be available for millions of stars.
The purpose of the proposed PhD project concerns Beta Cephei stars, hot, massive main sequence pulsators that are tomorrow's supernovae. Preparatory work for TESS has almost tripled the number of known Beta Cephei stars to over 600, but TESS itself is permanently increasing this number. Therefore we now have the luxury of cherrypicking the best targets for in-depth asteroseismic studies.
These best targets can be separated in two groups, pulsators in eclipsing binary systems and pulsating runaway stars, which are stars that have been ejected from the Galactic plane by some catastrophic event such as a supernova explosion or binary star disruption. From the eclipsing binary stars, one obtains accurate constraints on the masses of the components, whereas the runaway stars provide upper limits to the ages of the pulsators.
The task of the PhD student working on this project is to select the best possible targets for this effort, to obtain and analyse additional observational data necessary for their further study, and to model the stellar interiors precisely in close collaboration with known specialists in this area. In this way, our knowledge of individual pulsators and hence on massive stars in general shall be considerably improved. This PhD work is expected to result in several high-impact publications and should firmly establish the candidate in the scientific community.

Location: Warsaw

Subject: Asteroseismology for the masses - pulsations in binary stars

Supervisor: Prof. Gerald Handler (contact: gerald@camk.edu.pl)

Recent and ongoing ultra-precise space photometry missions have discovered a large number of new phenomena in binary and pulsating stars. These range from newly discovered pulsators in eclipsing binary stars over hot massive stars with unknown, possibly evolved companions to the new class of "single-sided pulsators", components of close binaries whose pulsation axis has been tilted into the orbital plane by the gravitational pull of a close companion.
The purpose of the proposed PhD project are in-depth studies of a carefully selected, scientifically valuable sample of these stars. Pulsators in binaries with total eclipses can be characterized in detail both in their exterior and their interior. In particular, stellar masses can be determined to high precision to calibrate the top of the mass function. The inference of the nature of presently unknown, possibly degenerate, companions of massive binary stars has a direct impact on binary stellar evolution theories. The extent of the phenomenon of single-sided pulsators is presently unknown and needs to be charted.
The task of the PhD student working on this project is to select the best possible targets for this effort, to obtain and analyse additional observational data necessary for their further study (in particular high-resolution, high signal-to-noise spectroscopy), to model the stellar interiors precisely, to determine stellar masses accurately, all in close collaboration with known specialists in this area. In this way, our knowledge of individual pulsators and hence on massive stars in general shall be considerably improved. This PhD work is expected to result in several high-impact publications and should firmly establish the candidate in the scientific community.

Location: Warsaw

Subject: Modelling relativistic stars

Supervisor: Dr hab. Bryn Haskell (contact: bhaskell@camk.edu.pl)

Neutron stars are one of the most exotic and exciting nuclear physics laboratories in the Universe. With a mass comparable to that of the Sun squeezed into a 10 km radius they have interior densities that exceed nuclear saturation density. These are conditions that we cannot replicate with laboratory experiments on Earth and allow us to catch a glimpse of the behaviour of matter at high densities and low temperatures, with exotic phases, such as deconfined quark condensates, expected in the core of these stars.
The recent detection of gravitational waves from binary neutron star mergers has opened a new window on the fascinating physics of these objects, but theoretical models and numerical simulations are needed to interpret the data and extract information from astrophysical measurements.
PhD projects are available on the topic of dissipation and transport in general relativistic simulations of neutron star mergers. The work will be carried out in collaboration with the group of Prof. Sebastiano Bernuzzi at the University of Jena, where the applicant will be expected to spend part of their time.

Location: Warsaw

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

Supervisors: Dr hab. Krzysztof Hełminiak (contact: xysiek@ncac.torun.pl), Prof. Maciej Konacki (contact: maciej@ncac.torun.pl)

The aim of the project (1) 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.
The aim of the project (2) 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).
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.

Funding: This offer is accompanied by a scholarship competition from the National Science Center OPUS project, number 2017/27/B/ST9/02727, entitled “Stellar astronomy with a global network of robotic telescopes Solaris” led by prof. Maciej Konacki. Scholarship in the total amount of 3500 PLN/month, gross, is available for 20 months. During the first year scholarship will be supplemented by the Institute to the total amount of 4500 PLN/month, gross

Location: Toruń

Subject: Astrophysics of stellar-merger remnants with interferometric techniques

Supervisor: Dr Tomasz Kamiński (contact: tomkam@ncac.torun.pl; https://www.ncac.torun.pl/~tomkam/index.html#mergestars)

We invite applications for two Ph.D. positions in astrophysics at the Nicolaus Copernicus Astronomical Center (NCAC) of the Polish Academy of Sciences in Toruń, Poland. The scholarships will be executed in Department for Astrophysics which is a NCAC branch located in the beautiful old town of Toruń.
The Ph.D. candidates will investigate the physical and chemical structure of remnants of red nova eruptions. The remnants are thought to be sites of recent stellar merger events. The main science aims include investigating physical processes that govern the common-envelope phase, stellar-collisions, mass loss in binaries, and binary interaction in eruptive systems. The Ph.D. candidates will work mainly with interferometric data acquired (1) in the infrared with VLTI instruments, Gravity and Matisse, or (2) similar submillimeter observations from ALMA and SMA arrays. Preferences of each Ph.D. candidate will be taken into account in deciding which of the two wavelength regimes, infrared or submillimeter, will constitute the main working material for their thesis. Most of the interferometric observations have been collected or are scheduled for execution in the near future. The Ph.D. candidates will be expected to develop optimal interferometric imaging techniques and investigate the physical structure of the remnants. The Ph.D. candidates will be also expected to secure multi-wavelength auxiliary data at other facilities (e.g. NASA IRTF, SOFIA, and VLT). Frequent training trips to ESO (Garching & Santiago) and interferometry schools are foreseen during the course.
To learn more on the science project, see: https://www.ncac.torun.pl/~tomkam/index.html#mergestars
A prior experience with interferometric data (infrared or submillimeter) or molecular spectroscopy are welcome but are not required. Proficiency in python programming will be considered as an asset. Applicants should hold (or expect to obtain before the start of the position) a university degree (master or equivalent) in the field of astrophysics, astronomy, or physics.
The monthly scholarship is competitive considering the current costs of living in Toruń and is higher than the typical respective wages at Polish universities.

Funding: This offer is accompanied by a scholarship competition from the National Science Center Sonata BIS project, number 2018/30/E/ST9/00398, entitled "Stellar mergers: causes and aftermath of stellar collisions investigated with interferometric methods" led by dr Tomasz Kamiński. Scholarship in the total amount of 4500 PLN/month, gross, is available for 4 years.

Location: Toruń

Subject: From transitional pulsars to ULXs, radiation, jets and winds in neutron stars

Supervisor: Prof. Włodek Kluźniak (contact: wlodek@camk.edu.pl)

The student will perform theoretical investigations of neutron stars in X-ray binaries (such as transitional pulsars, atoll and Z sources, ULXs) by performing numerical simulations of accretion onto magnetized neutron stars at various mass transfer rates, using PLUTO, KORAL, or similar codes.

Funding: This offer is accompanied by a scholarship competition from the National Science Center OPUS project, number 019/33/B/ST9/01564, entitled "From transitional pulsars to ULXs,radiation, jets and winds in neutron stars" led by prof. Włodzimierz Kluźniak. Scholarship in the total amount of 5000 PLN/month, gross, is available for 30 months.

Location: Warsaw

Subject: Relativistic astrophysics

Supervisor: Prof. Włodek Kluźniak (contact: wlodek@camk.edu.pl)

PhD studies in a range of topics in theoretical astrophysics are offered including, but not limited to, the astrophysics of black holes and neutron stars. These include phenomena as diverse as TeV emission, gamma-ray bursts (GRBs), gravitational waves, the (magneto)hydrodynamics of accretion disks and jets, binary evolution. Work on these topics will be relevant to ongoing and future observations with several modern and planned instruments, including H.E.S.S., LIGO/VIRGO, CTA, ATHENA and a host of optical, radio and X-ray telescopes.
Among specific topics of current interest are studies of the variability and stability of accretion disks in the presence of strong radiation fields. Prospective graduate students would be welcome to perform radiative MHD simulations of accretion disks with existing codes, as well as to work on improving radiation routines.
Work on simulations of coalescence and tidal disruption is also possible.

Location: Warsaw

Subject: Novae with evolved donors

Supervisor: Prof. Joanna Mikołajewska (contact: mikolaj@camk.edu.pl)

The proposed research is related to the OPUS grant “Life cycles of novae with evolved donors” led by prof. Joanna Mikołajewska and funded by the Polish National Science Centre. The scholarship is available for graduate students with a BSc degree and PhD students in astronomy or astrophysics, fluent in English, with good knowledge of IRAF, especially spectroscopy-dedicated packages, and Virtual Observatory tools. A basic knowledge of numerical methods and programming will be also appreciated. Any questions concerning the project should be sent to mikolaj@camk.edu.pl.

Funding: This offer is accompanied by a scholarship competition from the National Science Center OPUS project, number 2017/27/B/ST9/01940, entitled "Life cycles of novae with evolved donors" led by prof. Joanna Mikołajewska. Scholarship in the total amount of 4500 PLN/month, gross, is available for 18 months.

Location: Warsaw

Subject: Late-type variables in the Local Group of Galaxies

Supervisor: Prof. Joanna Mikolajewska (contact: mikolaj@camk.edu.pl)

The proposed PhD topic is built on recently completed spectroscopic survey of M33 and M31 for symbiotic stars led by prof. Joanna Mikołajewska. Among by-products of this survey are spectra of over 1000 red stars among them are many red variables, cepheids, and other variables classified based on only photometric characteristics (color-color and/or color-magnitude diagrams) and light curves, and that have never been spectroscopically confirmed. Many of ~200 symbiotic stars discovered by our survey are misclassified cepheids, W Vir-type and other variables which are completely different objects from symbiotic binaries. The proposed research is to explore this spectroscopic database in combination with the light curves, and other data to address the true physical nature of these variables.

Location: Warsaw

Subject: Kinetic simulations of relativistic magnetic reconnection

Supervisor: Dr hab. Krzysztof Nalewajko (contact: knalew@camk.edu.pl; http://users.camk.edu.pl/knalew/)

Magnetic reconnection is one of the most promising dissipation mechanisms in relativistically magnetized plasma, that is thought to be present in most astrophysical sources of gamma-ray radiation: relativistic jets of active galaxies (blazars), gamma-ray bursts, pulsars, magnetars, etc. In recent years, a significant progress was made in understanding the particle acceleration and production of gamma rays during relativistic reconnection, mainly due to kinetic numerical simulations ('particle-in-cell’ algorithm; PIC). Nevertheless, there are many outstanding problems regarding both numerical simulations as well as application of the numerical results to specific astrophysical situations. We seek PhD candidates with either numerical or theoretical skills. We offer introduction to: basic plasma physics, theory of magnetic reconnection, gamma-ray astrophysics, high performance computing, as well as working with a PIC code (Zeltron).

Location: Warsaw

Subject: Massive eclipsing binaries as a perfect laboratory measuring cosmic distances and studying stellar evolution

Supervisor: Prof. dr hab. Grzegorz Pietrzyński (contact: pietrzyn@camk.edu.pl)

Co-Supervisor: Dr Bogumił Pilecki (contact: pilecki@camk.edu.pl)

Applications are invited for one PhD position and accompanied scholarship at the Nicolaus Copernicus Astronomical Center (NCAC), in Warsaw, Poland, in the field of extragalactic distance scale. The successful applicant will work with Prof. Grzegorz Pietrzyński on the project “Massive eclipsing binaries as a perfect laboratory measuring cosmic distances and studying stellar evolution” funded by the National Science Centre. The work will include the analysis of high-resolution spectra, optical and near infrared photometry with the aim to measure precise and accurate distances to Galactic and extragalactic objects. Since the team operate a dedicated observatory located at Cerro Armazones (on the same place where E-ELT is building) experience in instrumentation and dedication to observations will be an advantage. The project may also include modeling of the observed eclipsing binary systems and a mass analysis of data. A knowledge of a modern programming language (e.g. Python) and other computer skills will be an asset.

Funding: This offer is accompanied by a scholarship competition from the National Science Center Beethoven Classic project, number 2018/31/G/ST9/03050, entitled "Massive eclipsing binaries as a perfect laboratory measuring cosmic distances and studying stellar evolution" led by prof. Grzegorz Pietrzyński and prof. Rolf Chini. Scholarship in the total amount of 4500 PLN/month, gross, is available for 3 years.

Location: Warsaw

Subject: Development of novel wavelength shifters for future dark matter detectors

Supervisor: Prof. Leszek Roszkowski (CAMK PAN)
Co-supervisor: Dr Marcin Kuźniak (CAMK PAN, contact: mkuzniak@camk.edu.pl)
Co-supervisor: Prof. Cristiano Galbiati (Princeton and GSSI, Italy)

Liquid argon based dark matter detectors currently taking data (DEAP-3600) or planned (DarkSide-20k, Argo) have a significant potential to discover Weakly Interacting Massive Particles (WIMPs) and will reach the ultimate sensitivity accessible to such searches. In such detectors, wavelength shifter (WLS) materials are used to convert argon scintillation light (at 128 nm) to visible wavelengths, which can be efficiently detected by standard sensors. This project involves comparative study of the most commonly used WLS and its novel alternatives, and selecting the best candidate tailored for specific application in the planned experiments, which would lead to extending their physics reach. Another aspect of this study is the compatibility of such new materials with silicon photomultipliers (SiPM) used by DarkSide-20k, quantifying their impact on the sensitivity of future experiments, and optimizing the light collection with Monte Carlo simulations.
The scope of this work includes R&D shared with collaborating institutions in Poland, Germany, Italy and Canada, and participation in development and installation of SiPM and WLS for the DarkSide-20k veto at Laboratori Nazionali del Gran Sasso (Italy).
The position is available for up to four years. The candidate is expected to have master degree in physics or astronomy at the starting date.
Note: This project is optionally available as a dual PhD program with Gran Sasso Science Institute (GSSI), leading to two PhD degrees (one in Poland and one in Italy); the successful candidate must satisfy PhD requirements of both CAMK PAN and GSSI. It will possibly involve extended visits to GSSI and Carleton University (Canada).

Location: Warsaw

Subject: Optimization of pulse-shape discrimination for liquid argon based dark matter searches using silicon photomultipliers

Supervisor: Prof. Leszek Roszkowski (CAMK PAN)
Co-supervisor: Dr Marcin Kuźniak (CAMK PAN, contact: mkuzniak@camk.edu.pl)
Co-supervisor: Dr Davide Franco (Astroparticle and Cosmology (APC) laboratory in Paris, France)

Liquid argon based dark matter detectors currently taking data (DEAP-3600) or planned (DarkSide-20k, Argo) have a significant potential to discover Weakly Interacting Massive Particles (WIMPs) and will reach the ultimate sensitivity accessible to such searches. With silicon photomultipliers (SiPM), recently introduced novel light sensors to be used by the next round of experiments, pulse-shape discrimination (the key technique necessary to mitigate backgrounds in liquid argon), requires computational and experimental studies necessary to optimize it for better sensitivity to WIMPs.
This project includes testing of novel SiPM modules developed by the DarkSide collaboration, as well as the cutting-edge digital version of SiPMs, which is under development for future detectors at Laboratori Nazionali del Gran Sasso (INFN) Torino, the Universite de Sherbrooke (Canada) and elsewhere.
Data from small and intermediate scale prototype detectors operated by the Global Argon Dark Matter Collaboration will be available for this analysis, with the goal of extracting important physics results with the optimized method.
The position is available for up to four years. The candidate is expected to have master degree in physics or astronomy at the starting date.
Note: This project is optionally available as a dual PhD program with the Astroparticle and Cosmology (APC) laboratory in Paris, leading to two PhD degrees (one in Poland and one in France); the successful candidate must satisfy PhD requirements of both CAMK PAN and APC. Long-term visits to APC and other collaborating institutions will optionally be offered.

Location: Warsaw

Subject: Measurement of nuclear recoils in liquid argon for dark matter searches

Supervisor: Prof. Leszek Roszkowski (CAMK PAN)
Co-supervisor: Dr Masayuki Wada (CAMK PAN, contact: masayuki@camk.edu.pl)
Co-supervisor: Prof. Cristiano Galbiati (Princeton and GSSI, Italy)

Today, dark matter represents the first evidence for new physics beyond the Standard Model, which is extremely successful to explain all observed phenomena in experimental particle physics, including the recent discovery of the Higgs boson. Currently, DarkSide, a liquid argon-based direct dark matter search experiment, has world-leading sensitivity for light dark matter candidates. The detailed characterization of liquid argon response to nuclear recoils (possible signals from dark matter particles) at low energy is essential to extend the sensitivity to lighter dark matter particles.

This project involves research on different aspects of the liquid-argon Time Projection Chamber (TPC) including designing and building of TPC, handling cryogenic system, simulating detector response using GEANT4, data acquisition, and analysis to draw physics results. Within this project, the obtained results will be used to re-analyze available data from DarkSide-50 experiment, which could lead to the world-best results for light dark matter search.

Note: This project is optionally available as a dual PhD program with Gran Sasso Science Institute (GSSI), leading to two PhD degrees (one in Poland and one in Italy); the successful candidate must satisfy PhD requirements of both CAMK PAN and GSSI. Long-term visits to GSSI will optionally be funded.

Location: Warsaw

Subject: Development of ultra-radiopure photodetector and light guides for dark matter direct search and neutrinoless double beta decay experiment

Supervisor: Prof. Leszek Roszkowski (Astrocent, CAMK PAN)
Co-supervisor: Dr Masayuki Wada (Astrocent, CAMK PAN, contact: masayuki@camk.edu.pl)
Co-supervisor: Prof. Cristiano Galbiati (Princeton and GSSI, Italy)

In rare event search experiments, such as dark matter searches and neutrinoless double beta decay searches, background event rates have to be suppressed below expected signal rates. In order to reach ultimate sensitivities for those searches, background contributions from detector components need to be suppressed. In this project, we focus on the photodetectors (silicon-based photodetector modules and light guides), which is a leading background contributor in both dark matter and neutrinoless double beta decay searches.

This project involves research on different aspects of the photodetector in cryogenic temperature including searching for radiopure components for the photo-detector and light guide, assaying materials, handling cryogenic systems, and optimization of coupling between the photodetector and the light guide. This project also aims to design a photodetector module and to estimate sensitivities for future experiments.

Location: Warsaw

Subject: Pulsar studies in Very-High-Energy domain of radiation

Supervisors: Prof. Bronislaw Rudak (contact: bronek@camk.edu.pl), dr hab. Jarosław Dyks

Pulsar astrophysics has gained new momentum after pulsed emission in the VHE domain (i.e. above 100 GeV) of gamma-rays have been discovered from the Crab pulsar (MAGIC, VERITAS) and the Vela pulsar (HESS). The PhD project will consist of observations and data analysis of selected pulsars with subsequent numerical modeling of the inferred pulsar properties in the VHE domain. Observational part will be carried out within the HESS Collaboration (www.mpi-hd.mpg.de/hfm/HESS/). Theoretical part will be to work out a physical model of the processes responsible for the origin of the VHE spectral componentt. The student will join the H.E.S.S. Collaboration and the Cherenkov Telescope Array Project during her/his PhD studies.

Location: Toruń

Subject: Stars in Open Clusters as Reference Objects for Large Spectroscopic Surveys

Supervisor: Dr hab. Rodolfo Smiljanic (contact: rsmiljanic@camk.edu.pl, http://users.camk.edu.pl/rsmiljanic)

Stellar astrophysics is nowadays going through an “industrial revolution”. The amount of observational data now available is staggering. A variety of stellar surveys are measuring different stellar properties: photometric, spectroscopic, asteroseismic, and astrometric. Thanks to these data, we can now characterise properties of stars to a level of precision and accuracy that has never been possible before.
In addition, a number of different (and sometimes quite complicated) methods are being (have been) developed to analyse all these data in an automatic way, as careful analyses of every single
individual star (in samples reaching millions of spectra) are just impossible. The output and limitations of these methods need to be understood in terms of zero point and stochastic uncertainties.
The aim of this project is to perform an in-depth, careful, and high-quality analysis of F-, G-, and K-type stars members from a few well-known open clusters, determining their atmospheric parameters and detailed chemical abundances. The first goal of this analysis is to provide an extended list of stellar astrophysical calibrators, in distinct evolutionary stages, that can be used as reference objects in current and future large spectroscopic surveys. We will use all possible data that is available (photometry, spectroscopy and Gaia astrometry). Secondary goals include looking for signs of planet formation in the chemical abundances (refractory vs. volatile elements) and investigating the chemical homogeneity of stars in clusters, with applications to chemical tagging in Galactic archaeology.

Location: Warsaw

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

Supervisor: Dr hab. Radosław Smolec (contact: 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.

Funding: This offer is accompanied by a scholarship competition from the National Science Center Sonata BIS project, number 2018/30/E/ST9/00598, entitled "Classical Cepheids as testbeds for stellar evolution and pulsation theories" led by dr hab. Radosław Smolec. Scholarship in the total amount of 4500 PLN/month, gross, is available for 4 years.

Location: Warsaw