Tuorlan observatorio
Tuorlan observatorio

Juri Poutanen

Juri Poutanen,
Professor of Astronomy,
Director of Tuorla Observatory

Research group
Curriculum Vitae
Astrophysical calculator
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Welcome to my web site. After 12 years in Oulu close to the polar circle and the Santa Claus village, I have moved to Tuorla Observatory, University of Turku. This is almost in the tropics, since it lies at 60.4 degrees North only.

My group studies accretion-powered high energy sources such as neutron stars and black holes. Our strength is the combination of observational and theoretical research. We are actively involved in the analysis of the data on blazars, black holes X-ray binaries, X-ray pulsars and X-ray bursters, as well as ultraluminous X-ray sources obtained with the X-ray and gamma-ray observatories such as RXTE, XMM-Newton, INTEGRAL, Fermii and Nustar. We also develop theoretical models for accretion discs around neutron stars and black holes, particularly super-Eddington accretion discs around black holes and X-ray pulsars. We have pioneered theoretical modelling of the light curves from rapidly rotating neutron stars and have developed state-of-the-art computer code for modelling the radiative processes in relativistic plasmas. We have developed the most accurate atmosphere models for hot neutron stars with the aim to understand the emission properties during X-ray bursts and to obtain useful constraints on the neutron star masses and radii and therefore on the equation of state of cold dense matter. Furthermore, we work on physical models for the correlated optical/X-ray variability of accreting black holes, in particular, we developed models for quasi-period oscillations. We also make polarimetric observations in the optical of accreting black holes with the state-of-the-art polarimeter Dipol.  

 We work on the analysis of the Fermi/LAT data from blazars, which are supermassive blackholes with relativistic jets pointing towards us and emitting most of the energy in the GeV range. We have found that their spectra have significant breaks in the GeV range that are well described by the absorption of the gamma-rays due to the photon-photon pair production on He II Lyman recombination continuum and lines. This has resolved a long-standing question of gamma-ray production and proved that gamma-rays are produced within the broad-band line region. We have also proposed a novel particle acceleration mechanism--"photon breeding"-- that operates in relativistic jets emanating from active galactic nuclei.

Contact details:

Tuorla Observatory, Department of Physics and Astronomy, FIN-20014 University of Turku, Finland
Phone: +358-400-640684
E-mail: juri.poutanen at utu.fi

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