Study of the TeV blazar Mrk 501 with mm-VLBI
Speaker: Dr. Koyama, Shoko 小山翔子
Institute of Astronomy and Astrophysics, Academia Sinica
Time: 15:30pm 8th June, 2018 (Friday)
Venue: R521, IoA, 2nd General Building 綜二館R521
Probing the precise location and the structure of the relativistic jets is a fundamental issue for understanding jet launching and collimation mechanisms. High-resolution Very Long Baseline Interferometry (VLBI) observations of the nearby radio galaxy M87 have revealed the precise location of the radio core and the clear limb-brightened structure, and these allowed to study the jet collimation profile and probe the jet foot point. However, intensive studies have not been performed for blazars.
TeV blazar Mrk 501 is a suitable target for this study, thanks to its proximity, brightness, and massiveness of the black hole.
We have performed multi-epoch astrometric observations of the radio core in Mrk 501 with the VLBI Exploration of Radio Astronomy (VERA) and the Very Long Baseline Interferometry (VLBA) at 7 mm. We find that the radio core of Mrk 501 relative to distant reference sources did not move significantly, and their locations were confined within ~200 microarcseconds diameter region. The jet profile shows parabolically collimated structure. We will discuss the origin of the relativistic jet, either black hole accretion flow or spinning black hole, and further compare these results with those of M87. We also present our prospects with the Event Horizon Telescope (EHT) plus ALMA VLBI observations at 1 mm including our Greenland Telescope, to probe further detailed structure and size of the emission region.