Title: Accretion at Eddington rates: the curious case of IGR J17091-3624 and GRS 1915+105  

Speaker: Diego Altamirano (Univ. of Southampton)  

Time & Place: Thursday, 3:00pm,May 22nd , Lecture Hall, 3rd floor   

Abstract: IGR J17091-3624 and GRS 1915+105 are two Galactic black-hole systems which have attracted particular interest in the scientific community as they are the only sources known to show bizarre, high-amplitude, highly-structured X-ray variability. These sources are thought to be of particular importance for our understanding of accretion disk physics, as they have been observed to accrete at Eddington rates for longer periods of time than any other known Galactic system. In this talk I will present results based on RXTE, Swift, INTEGRAL and XMM-Newton observations and review what we have learn so far from the comparison between IGR J17091-3624 and GRS 1915+105. I will argue that current observations indicate that all models requiring near Eddington luminosities for the highly-structured X-ray variability might fail. 

Related publications:  

http://adsabs.harvard.edu/abs/2011ApJ...742L..17A  

http://adsabs.harvard.edu/abs/2011A%26A...533L...4R  

http://adsabs.harvard.edu/abs/2012ApJ...747L...4A  

http://adsabs.harvard.edu/abs/2012MNRAS.422L..91W  

http://adsabs.harvard.edu/abs/2012ApJ...746L..20K  

http://adsabs.harvard.edu/abs/2013ApJ...778...46P   

Biog: Dr Diego Altamirano studied Astronomy at the University of La Plata, Argentina. After graduating with honors (10 out of 10 in his master thesis), he moved to the Netherlands to do this PhD under the supervision of Prof. Michiel van der Klis. During the 4 years period, he focused in the study of X-ray observations of neutron-star and black-hole Low-mass X-ray binaries. He has worked and published in several areas of high-energy astrophysics, including (stable and unstable) thermonuclear burning on the surface of neutron stars, accretion-powered and nuclear-powered millisecond X-ray pulsars and quasi-periodic oscillations in both neutron star and black holes. After obtaining his PhD degree in 2008, he was offered a 5 years Postdoc position at the University of Amsterdam to continue his independent work. In 2013 he was awarded the prestigious University Research Fellowship from the UK Royal Society and he now holds the position of Senior Research Fellow at the University of Southampton.