GMVA16A-293

Zeroing in on Sgr A*: polarization characteristics and source symmetry at 3 mm

Abstract

VLBI observations of the radio source Sagittarius A* associated
with the supermassive black hole candidate at the Galactic center have
shown that its apparent size is a convolution of its intrinsic size
and a scattering size, the relative contributions of which depend on
the observing frequency. Knowledge of the intrinsic size and the
orientation of the polarized emission is important for constraining the
parameter space of different emisison models.
At 3mm the expected intrinsic size of the
emission region is 10R_S, directly outside the shadow region
at ~5R_S. Preliminary analysis of our recent single-polarization VLBA+GBT+LMT
observations at 3mm reveal zero closure phases indicating a symmetric
geometry. Here we propose the first high-sensitivity, dual-polarization
GMVA+LMT observation of SgrA* at 3mm. This will allow us to
constrain the structure of the polarized emission - a step forward to
pinpoint the nature of this intriguing source.

Investigators

Name	Institution
Jonathan Leon-Tavares	Astrofísica, Óptica y Electrónica, Instituto Nacional de
Grant Wilson	Massachusetts at Amherst, University of
Alfredo Montana	Astrofísica, Óptica y Electrónica, Instituto Nacional de
David Sanchez-Arguelles	Astrofísica, Óptica y Electrónica, Instituto Nacional de
David Hughes	Astrofísica, Óptica y Electrónica, Instituto Nacional de
Laurent Loinard	México, Universidad Nacional Autónoma de
Tony Zensus	National Radio Astronomy Observatory; Max-Planck-Institut für Radioastronomie
Adam Deller	Swinburne University of Technology
Ciriaco Goddi	Center for Astrophysics | Harvard & Smithsonian; European Southern Observatory; Joint Institute for Very Long Baseline Interferometry European Research Infrastructure Consortium; Nijmegen, Radboud Universiteit
Raquel Fraga-Encinas	Nijmegen, Radboud Universiteit
Remo Tilanus	Arizona, University of
Michael Kramer	Manchester, University of; Max-Planck-Institut für Radioastronomie
Thomas Krichbaum	Max-Planck-Institut für Radioastronomie
Geoffrey Bower	Academia Sinica
Monika Moscibrodzka	Nijmegen, Radboud Universiteit
Heino Falcke	Netherlands Institute for Radio Astronomy; Nijmegen, Radboud Universiteit
Christiaan Brinkerink	Nijmegen, Radboud Universiteit
Cornelia Mueller *	Würzburg, Universität; Nijmegen, Radboud Universiteit; Astronomical Institute of the University of Erlangen-Nuremburg

* indicates the PI