Multi-Wavelength Studies of Compact Objects: Physics, Populations, and Origins

University Of Florida, Gainesville FL

Investigators

Abstract

The overall goal of this project is to understand the physics, populations and origins of black hole X-ray binaries - particularly those systems known as "microquasars" - and the physical conditions/processes which lead to the formation of relativistic jets in some of them. While astronomers have studied relativistic outflows from black hole systems for several decades, the details of the mechanism which accelerates and collimates such a jet at nearly the speed of light out of the black hole potential well remains a mystery. The scientific path taken here employs multi-wavelength studies of the physics of compact objects (particularly microquasars) and the populations and origins of compact objects in our Galaxy and beyond. With the addition of more than 2000 new X-ray sources recently discovered in the Galactic Center there is an opportunity to expand the sample size of accreting compact objects in general, and black hole binaries in particular, by an order of magnitude, enabling the use of population statistics to constrain the origin and evolution of even rare classes of X-ray binary such as microquasars. Furthermore, it is now possible to study the environment in which many of these systems form, to examine the feedback process between X-ray binaries and their environment. This combination of both detailed studies of individual sources and broader investigation of their origins and properties via population studies provides a powerful synergistic approach to addressing both problems. Towards this end, several programs will be carried out by Drs. Eikenberry and Bandyopadhyay, including a search for new microquasars and other compact systems using 13 nights of guaranteed time with FLAMINGOS-2 on Gemini South. The resulting spectra of approximately 2000 candidate infrared counterparts to new X-ray sources in the Galactic center are expected to yield between 200 to 300 new binaries with compact object secondaries. Also included in this work will be the development of an infrared extinction map of the Galactic center using data from the UKIDSS Galactic Plane Survey (which will be necessary to accurately reddening-correct the photometry of stars observed with FLAMINGOS-2). Multiwavelength studies of the black hole candidate GRS1915+105 will be carried out and used to develop/refine Dr. Eikenberry's "magnetic bomb" model of relativistic jet formation and its relation to the Accretion Ejection Instability model. Dr. Eikenberry's multi-wavelength program to find X-ray sources in young clusters (in which the cluster properties are used to constrain the progenitor characteristics) will also be continued. This program will enable the education and training of four graduate students who will be involved in the project. The project will also support an ongoing hands-on outreach program at local Title 1 public schools with large minority populations.