5) Studies of world cultural heritage paintings using optical coherence tomography
In the years 2009-2014 a group of scientists form the Institute of Physics and from the Institute for the Study, Conservation and Restoration of Cultural Heritage, Faculty of Fine Arts, both of Nicolaus Copernicus University, working in consortium 21 partners of the project CHARISMA of EU 7th Framework Programme developed specialised, portable very high resolution optical coherence tomograph (OCT) designed especially for non-invasive examination of cultural heritage objects. Inspection of such objects is always carried out at the invitation of the object’s owner or curator and contributes to better understanding of the structure of the work of art and to determination of its state of preservation. It is necessary, among others, for proper planning of conservation and restoration campaign. Without this knowledge such treatments would be burdened with a high risk of damage to the object and therefore are necessary especially in case of most valuable artworks. It should be emphasized that the group headed by prof. Piotr Targowski and comprising researchers form the Institute of Physics and from the Institute for the Study, Conservation and Restoration of Cultural Heritage as one of the few in the word has access to most valuable and best-known works of art. Among others, due to co-operation with Opficio delle Pietre Dure in Florence, it was possible to examine the monumental “Adoration of the Magi” by Leonardo da Vinci from the collection of Uffizi Gallery in Florence and also an attributed to Leonardo and his studio “The Landsdowne Virgin of the Yarnwinder” from a private collection. In 2013, by invitation of Royal Institute for Cultural Heritage (KIK/IRPA) in Brussels, panels from “Ghent Altarpiece” by van Eyck brothers was examined with OCT. In 2014 again for Opificio and for Galleria Nazionale delle Marche, Urbino “The Portrait of a Young Woman”, also known as “La Muta”, by Raphael was investigated. In 2016, by invitation of Cultural Heritage Agency of the Netherlands (RCE) the “Historical Painting 1626” by Rembrandt Harmenszoon van Rijn from the collection of Rijksmuseum in Amsterdam and famous “The Sunflowers” by Vincent van Gogh from van Gogh Museum were examined. This last session was a part of the broad examination campaign of this picture, carried out under Horison 2020 IPERION CH project, within MOLAB offer. In addition to the NCU (OCT) also University of Amsterdam and RCE (restoration issues), University of Antwerp (MaXRF), and The Università degli Studi di Perugia (FTIR) were involved. Among artworks in Polish collections the most precious objects examined were “The Last Judgment” by Hans Memling from the National Museum in Gdańsk and “The Passion of Christ” from the St. James Church in Toruń.
OCT tomography is under development in the Institute of Physics NCU mostly for medicine diagnostic, especially in ophthalmology. When applied for examination of works of art, in the case of easel paintings it enables the assessment of the condition, thickness and number of varnish layers, the analysis of the structure of glaze layers and the precise identification of the range of former restoration interventions. It can also be used for precise evaluation of the effectiveness and safety of planned restoration treatments such as removal of unwanted layers of varnishes and overpaintings. In addition to easel paintings, OCT is also used to study, among others, historic glass, amber artwork, glaze layers on ceramic and for inspection of other transparent coatings like furniture polish and lacquer.
Prof. Targowski is a President of the Governing Board of Polish Research Consortium for Heritage Science E-RIHS.PL
7) Discovery of periodic and alternating flares of the methanol and water masers in high-mass star-forming regions
A team of radio astronomers including Marian Szymczak, Anna Bartkiewicz, Marcin Gawroński, Paweł Wolak, and Mateusz Olech has discovered 34.4 day periodic flares of the 6.7 GHz methanol and 22 GHz water masers coupled in mutually exclusive pattern in one of the star forming regions monitored using the Torun 32 m dish. The methanol maser flares could be triggered by infrared photons which flux is modulated by cyclic accretion instabilities in a cicrcumstellar of protobinary disc. The accretion rate in a binary system may vary with the orbital phase switching between the methanol and water maser favouring conditions. This discovery is a part of the unique systematic, long-term monitoring of cosmic masers done at the NCU.
M. Szymczak et al., Monthly Notices of the Royal Astronomical Society 459 (2016), L56-L60
M. Szymczak et al., Monthly Notices of the Royal Astronomical Society 474 (2018), 219-253