The Crete Astrophysics Group hosts a world-class center for polarimetric studies of point sources in the optical, featuring cutting-edge, innovative instruments, international collaborations with world-leading groups in Instrumenation, Observations, and Theory, and a wide variety of applications, including studies of extragalactic jets, the interstellar medium, binaries, transient-follow ups, and study and control of foregrounds in the study of the polarization of the cosmic microwave background.

The RoboPol project involves studies with the RoboPol polarimeter, a unique, no-moving-parts optopolarimeter specifically designed for the 1.3 m telescope of the Skinakas Observatort. It is a collaboration between the University of Crete and FORTH in Greece, Caltech in the US, the Max-Plank Institute for Radio Astronomy in Germany, the Inter-University Center for Astronomy and Astrophysics (IUCAA) in India, and the Nicolaus Copernicus University in Poland. The primary research program of RoboPol is the polarimetric monitoring of blazars and the study of polarization angle swings that may be associated with gamma-ray flaring. The program has been running at Skinakas since 2013. RoboPol has been additionally used to study the magnetic field of translucent interstellar clouds, probe the nature of gamma-ray burst afterglows, and the polarized emission from/Be X-ray binaries.

The PASIPHAE (Polar-Area Stellar-Imaging in Polarization High-Accuracy Experiment) project is a planned 4-year polarization survey of all stars that are brighter than 16.5 magnitude in the R-band at high Galactic latitudes (latitudes higher than 50 degrees and lower than -50 degrees) in the northern and southern sky, with combined statistical and systematic accuracy of 0.1%. PASIPHAE will use novel innovative polarimeters, currently under development at IUCAA, that build on the technology of RoboPol, expanding its high-accuracy capabilities to a large field of view, and further imporving on its systematic uncertainties. PASIPHAE is a collaboration between the Crete Astrophysics Group, Caltech in the US, IUCAA in India, and the South African Astronomical Observatory. The PASIPHAE survey will, for the first time, enable us to perform on large scales Magnetic Tomography of the Interstellar Medium (a technique developed by our group), which can in turn be used to drastically improve the accuracy with which polarized emission from dust (the major foreground in studies of CMB polarization) can be subtracted from CMB data, to allow for much higher sensitivity searches for inflationary B-modes. PASIPHAE is made possible by a grant from the Stavros Niarchos Foundation, and is additionally funded by the Infosys Foundation and the South African NRF.


K. Tassis, V. Pavlidou, D. Blinov, G. Panopoulou, I. Liodakis, I. Komis