VLBA12B-263

Probing the Jet Structure of M87 with 86 GHz Imaging and Core-Shift Astrometry

Abstract

We propose the high-sensitivity (VLBA+GBT) 86-GHz observations of the nearby radio galaxy M 87 in combination with a quasi-simultaneous (as possible as within ~one-month separation), multi-frequency phase-referencing observation at 1.4, 5, 2/8, 15, 22 and 43 GHz (VLBA alone). The aim is to reveal the exact collimation profile of the M87 jet within 100 Schwarzschild radii from the central engine by investigating the radial distributions of the core size and the transverse width of the edge-brightened jet, and then to obtain a firm evidence for a change of the collimation profile, as discovered by our preliminary investigation. This is a progressive study of our previous work (Hada et al. 2011, Nature 477, 185). We ask for the total observing time of 25 hours, which consists of 8 hours x 2 days (86 GHz, VLBA+GBT) + 9 hours x 1 day (1.4-43 GHz, VLBA).

Investigators

Name	Institution
Kazuhiro Hada *	Istituto Nazionale di Astrofisica; National Astronomical Observatory of Japan ; Nagoya City University
Akihiro Doi	Japan Aerospace Exploration Agency
Motoki Kino	National Astronomical Observatory of Japan ; Korea Astronomy and Space Science Institute
Hiroshi Nagai	National Astronomical Observatory of Japan
GBT Operator	Green Bank Observatory

* indicates the PI