The Subaru Seminar is
usually held in Room 104 of the Hilo Base Facility, adjacent
to the main lobby. Everyone is welcome to attend. If you are
interested in giving a seminar, please contact Subaru seminar organizers
(Tae-Soo Pyo, Sherry Yeh, Nagayoshi Ohashi)
by email : sseminar_at_subaru.naoj.org (please change"_at" to @).
April 3, Thursday, at 11:00 am
" Two Serendipitous Probes of Sagittarius A*: The Galactic Center Pulsar and The G2 Gas Cloud "
High resolution very long baseline interferometry (VLBI) images of nearby massive black holes have
the power to address fundamental questions about the physics of black holes. This includes
the most accurate constraints on the mass density of the black hole, detection of the black hole
spin, and exploration of extensions to general relativity (GR). In particular, Event Horizon
Telescope (EHT) observations will probe Sgr A* and M87, the two sources with the largest angular
diameter black holes on the sky, over the coming years with increasing sensitivity and accuracy in
imaging. Unfortunately, we do not fully understand the physical processes that are driving accretion and
outflow in these sources. To address the fundamental black hole physics questions, we need to develop a
deeper knowledge of the astrophysics of these sources.
The periastron passage of the G2 gas cloud with Sgr A* at ~1000 Schwarzschild in Spring of 2014 gives us an unprecedented opportunity to study a wide range of astrophysical models for accretion and outflow. I describe here observations from millimeter to X-ray wavelengths that enable us to create the necessary context for understanding physics at a few Schwarzschild radii. These include centimeter wavelength VLBI, millimeter polarimetry, and light curve analysis.
The serendipitous discovery of the Galactic Center magnetar, SGR 1745-29, has provided a powerful new probe of the Galactic Center environment, including the gas density, magnetic field strength, and nature of the interstellar scattering screen. The discovery also raises important questions about the detectability of pulsars in close orbit to Sgr A* and the pulsar population in the Galactic Center overall.
Seminars are also held at JAC,