41. PASSERBY BECOME SUPERNOVA HUNTERS IN KUNGSTRÄDGÅRDENTanja Petrushevska, S. Papadogiannakis, Emir Karamehmetoglu, 2015, other performed works Abstract: Fysik i Kungsträdgården is one of the major outreach events in Stockholm where scientists have the chance to show their research. This year the supernova group at the OKC invited the public to look for supernovae with us using the intermediate Palomar (Transient) Factory (iPTF) collaboration telescope in Palomar, California, U.S.A. Due to the time difference between Stockholm and California, we were able to look at live images as they were taken from the telescope, to search for new transient objects such as supernovae. The event was successful, bringing a lot of people from the park in central Stockholm to come and search with us.
Keywords: science outreach, supernova hunting for the public
Published in RUNG: 09.02.2018; Views: 3694; Downloads: 0
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43. Art or Science? Images of scientific research : Photography contestTanja Petrushevska, 2017, artistic work Abstract: Looking at the pinking of a sky at sunset we see a delicate impressionist watercolor or rather the spectacular effect of the refraction of the sun on the particles of the atmosphere? Can the extraordinary geometries of the cubic lattices of a salt crystal be considered a perfect composition deserving of admiration like a cubist painting? All the "infinite forms, ever more beautiful and wonderful" of life, as defined by the famous naturalist Charles Darwin, are art or science?
The Art or Science photo contest? was born to emphasize the contamination between these two fields, only apparently distant, of human knowledge, exalting the beauty of scientific research and rewarding the photographic talent of those who work in science.
The 2017 edition of the competition, conceived and promoted by the University of Trieste and Immaginario Scientifico, has collected 116 images of students and scientists from universities and research institutions. Among these were selected 30 photos, exhibited from 18 to 23 September 2017 in Trieste, at Palazzo Costanzi, as part of the Trieste Next-Festival of Scientific Research.
Keywords: art and science
Published in RUNG: 23.01.2018; Views: 3064; Downloads: 0
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45. Time- and angle-resolved photoemission spectroscopy with optimized high-harmonic pulses using frequency-doubled Ti:Sapphire lasersSteffen Eich, Jurij Urbančič, 2014, original scientific article Abstract: Time- and angle-resolved photoemission spectroscopy (trARPES) using femtosecond extreme ultraviolet high harmonics has recently emerged as a powerful tool for investigating ultrafast quasiparticle dynamics in correlated-electron materials. However, the full potential of this approach has not yet been achieved because, to date, high harmonics generated by 800 nm wavelength Ti:Sapphire lasers required a trade-off between photon flux, energy and time resolution. Photoemission spectroscopy requires a quasi-monochromatic output, but dispersive optical elements that select a single harmonic can significantly reduce the photon flux and time resolution. Here we show that 400 nm driven high harmonic extreme-ultraviolet trARPES is superior to using 800 nm laser drivers since it eliminates the need for any spectral selection, thereby increasing photon flux and energy resolution to <150 meV while preserving excellent time resolution of about 30 fs.
Keywords: angle-resolved photoemission spectroscopy, ARPES, high harmonic generation, ultrafast surface science
Published in RUNG: 20.04.2017; Views: 5203; Downloads: 0
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46. Self-amplified photo-induced gap quenching in a correlated electron materialMathias Stefan, Eich Steffen, Jurij Urbančič, 2016, original scientific article Abstract: Capturing the dynamic electronic band structure of a correlated material presents a powerful capability for uncovering the complex couplings between the electronic and structural degrees of freedom. When combined with ultrafast laser excitation, new phases of matter can result, since far-from-equilibrium excited states are instantaneously populated. Here, we elucidate a general relation between ultrafast non-equilibrium electron dynamics and the size of the characteristic energy gap in a correlated electron material. We show that carrier multiplication via impact ionization can be one of the most important processes in a gapped material, and that the speed of carrier multiplication critically depends on the size of the energy gap. In the case of the charge-density wave material 1T-TiSe 2 , our data indicate that carrier multiplication and gap dynamics mutually amplify each other, which explains—on a microscopic level—the extremely fast response of this material to ultrafast optical excitation.
Self-amplified photo-induced gap quenching in a correlated electron material. Available from: https://www.researchgate.net/publication/308804379_Self-amplified_photo-induced_gap_quenching_in_a_correlated_electron_material [accessed Apr 20, 2017].
Keywords: high harmonic generation, charge-density wave material, 1T-TiSe2, non-equilibrium electron dynamics, ultrafast surface science
Published in RUNG: 20.04.2017; Views: 5473; Downloads: 0
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