Community Research Highlights

High Energy Radiation from Jets and Accretion Disks Near Rapidly Rotating black Holes

Michael O’Riordain, Asaf Pe’er, University College Cork

Relativistic jets are among the most ubiquitous, fundamental phenomena seen in many different astronomical objects on many different scales. Despite being studied for several decades, the mechanism by which they are powered is still under debate. It is long thought that the main source of energy powering them is the rotational energy of a rapidly spinning black hole. This idea had been supported in recent years by interpreting observed correlations between radiation at radio frequencies (presumably originating from the jet) and spin measurements of black holes, enabled by precise X-ray measurements of radiation originating from the accretion disks. This correlation, however, was recently challenged by the UCC team lead by the graduate student M. O’Riordan under the supervision of A. Pe’er and in collaboration with numerical expert J. McKinney (University of Maryland, USA). The group used high-resolution general-relativistic numerical simulations  to investigate the high-frequency X-ray and γ-ray radiation from accreting black holes. Surprisingly, it was found that the dependence on spin strongly deviates from the expected correlation. This is a consequence of emission from plasma in the extremely warped spacetime near the event horizon of the spinning black hole.  For rapidly rotating black holes, observers see deeper into the hot, dense, highly magnetized regions of the accretion flow than in the non-spinning case, and so measure a much larger radiated flux. This result, which was recently published in the Astrophysical Journal, thus points to a more complicated mechanisms that are needed for launching of relativistic jets than previously thought, and further indicates the need for a more broad-band observational campaigned that could help resolve this mystery.

Jorick Vink, Armagh Observatory

Wolf-Rayet spin at low metallicity and its implication for black hole formation channels

Jorick Vink from Armagh Observatory and Planetarium has used the European Southern Observatory’s Very Large Telescope (the ESO VLT) – one of the world’s largest optical telescopes, to study some of the most extreme types of star that exist – Wolf Rayet stars – in our neighbouring galaxies the Large and Small Magellanic Clouds.  This study provides a proxy for understanding how star formation worked in the early days of our universe, when conditions were very different to now, and the stars made almost entirely of hydrogen and helium, without the heavier elements that are common today.…603A.120V

Eamon Ansbro, Space Exploration Ltd

We report the breakthrough development of a Quantum Super luminal Communications (QSC) system that is application specific for space communications.   The operations of the system provides instantaneous or real time communications to space probes and future manned space craft that may be travelling within the Solar System.  This addresses the problem of significant time delays that is inherent within existing space communications systems.

Eamon Ansbro, Space Exploration Ltd, Kingsland Observatory, NUI Galway and Tralee IT

Moonlight scattering is the largest component of the night sky.   A partnership of Space Exploration Ltd and Kingsland Observatory with both NUI Galway and Tralee IT have developed a prototype Moonlight Scatter Cut Filter that increases telescope observing time.   Early results have demonstrated at least a 25 per cent increase in telescope time.  This means that world class observatories such as European Southern Observatory could increase  telescope observing time by at least 30 nights per year.  This not only increases the number of useable nights, with significant reduction of costs and shortening the expensive periods required at telescopes, but importantly, will have significant impact on astronomy.