Astronomy Colloquium: Javier Garcia


Sep. 21, 2018, 3:45pm to 4:45pm

Campus Location

Office/Remote Location

Room 217


Javier Garcia from the Division of Physics, Mathematics and Astronomy at the California Institute of Technology will be the featured speaker at a Department of Physics and Astronomy colloquium. His talk is titled, "The Strong-Field Region near Black Holes and Neutron Stars."

In the region close to compact object such as black holes or neutron stars, the extreme conditions created by the strong gravitational field produces copious amounts of energetic radiation (ultra-violet, X-rays, and Gamma-rays). The interaction of this radiation with the surrounding material results in observables that carry important physical information. X-ray spectral and timing techniques provide direct access to the accretion physics on these systems, such as the black hole spin, inner-disk radius, ionization stage, among others. In this talk Garcia will discuss the current state of modern relativistic reflection models that have been recently computed and tailored specifically for (1) supermassive black holes in AGN and black hole binary systems in the hard state; (2) neutron star X-ray binaries; and (3) carbon and oxygen rich ultra-compact X-ray binaries. He will present the implementation of our new models to observational data from several X-ray observatories (RXTE, Swift, Chandra, XMM-Newton, Suzaku, NuSTAR, and NICER), and discuss current outstanding issues, such as the large iron abundances frequently required to fit the reflection spectra, controversies on the disk truncation in BHB, the origin of the soft excess in AGN, and the effects of high density in the observed spectra.

There will be refreshments starting at 3:30 p.m.

Admission Information

This event is free and open to the public.

Contact Information

External Sponsor

Department of Physics and Astronomy