O seminário será apresentado por Randy Campbell (Keck Observatory).
Resumo:
This presentation will cover the extreme evolution of an object known as X7, an elongated dust and gas feature, presently located half an arcsecond from the Galactic Center supermassive black hole. The observations cover two decades of high-angular-resolution near-infrared data from the W. M. Keck Observatory using both spectro-imaging observations of Br-γ line emission and Lp (3.8 μm) imaging data. The analysis provides the first estimate of its orbital parameters and quantitative characterization of the evolution of its morphology and mass. The leading edge of X7 appears to be on a mildly eccentric (e ∼ 0.3), relatively short-period (170 yr) orbit and is headed toward periapse passage, estimated to occur in ∼2036. Over the course of our observations, X7 has (1) become more elongated, with a current length-to-width ratio of 9, (2) maintained a very consistent long-axis orientation (position angle of 50°), (3) inverted its radial velocity differential from tip to tail from −50 to +80 km s−1 , and (4) sustained its total brightness (12.8 Lp magnitudes at the leading edge) and color temperature (425 K).
Randy Campbell is the Science Operations Lead Astronomer at the W. M. Keck Observatory, where is has been part of the staff for over 28 years. Randy leads a team of scientists and operators that provide visiting astronomers with observing support for using the Keck telescopes. He has technical expertise in developing and maintaining the instrumentation of the observatory, in particular the laser guide star adaptive optics (LGSAO) used to remove image blur caused by atmospheric turbulence. Randy’s research includes the study of classical novae, a type of cataclysmic variable star and Randy is a member of the UCLA Galactic Center Group where he contributes to studies of the gas and dust near the galactic blackhole and develops tools for three-dimensional visualization of data.
Google Meet: https://meet.google.com/pcw-gmem-jyi
Link da transmissão: https://www.youtube.com/c/AstronomiaIAGUSP/live