S E M I N A R IDepartament d'Astronomia i Astrofísica
Universitat de València
Dinnertime for SgrA* (The Black Hole in the Center of OUR Galaxy)
Harvard-Smithsonian Center for Astrophysics
Saló de Graus de Matemàtiques
Dimarts 02 octubre 2012
I will describe the developing efforts to image the environs of the black hole in the center of our galaxy at 230 GHz and higher with Very Long Baseline Interferometry (VLBI). The VLBI Array is called the Event Horizon Telescope (EHT). At 230 GHz the interstellar scattering and the source optical depth are sufficiently small that the immediate vicinity of the black hole can be discerned. The size of this image has a diameter of about 37 microarcseconds or about 4 Schwarzschild radii. Image quality should improve rapidly in the coming years as the EHT is formed and may provide new insight about general relativity in the strong gravity limit. We are at a phase of development similar to that of imaging Cygnus A in the early 1950s. Plans are under way to image SgrA* next spring when the newly discovered orbiting earth-sized mass, now known as "G2", will be tidally disrupted as it passes perihelion and may cause electromagnetic flaring activity. I will also describe the imaging of the innermost parts of the jets driven by the black holes in M87 and another AGN, 1924-293.