Letters of Intent received in 2016

LoI 2018-1911
High resolution and high precision astronomy

Topics

- Probing emission mechanism of relativistic jets, resolving relativistic outflows in AGN with space VLBI, probing jet formation
- Probing the innermost regions of AGN at 3 mm and 1 mm with ground-based VLBI including phased ALMA
- Detecting the shadow of the black hole in Sgr A* and M 87 with sub-mm VLBI and probing the physics close to the event horizon in the former with optical interferometry
- Ultimate resolutions in the presence of diffractive and refractive media
- Determining the masses of black holes in massive star clusters throughout the Milky Way with optical interferometry
- Uncovering details of mass accretion and jets in young stellar objects and AGN with optical interferometry
- Consolidating the fundamental catalogues of reference in the sky from VLBI observations of the international celestial reference frame and from Gaia

Fields covered: stellar and relativistic astrophysics, astrometry/geodesy, Even Horizon Telescope, SVLBI (RadioAstron), Gaia, VLTI (GRAVITY, MATISSE)

Rationale

Astronomical research made with a range of new and upgraded instrument drives the scientific endeavour to the limits of resolution and measurement precision and delivers fundamental results and breakthrough discoveries in a number of scientific fields, from stellar astrophysics and physics of black holes, to relativistic astrophysics and cosmology. This research will largely shape the astronomical landscape over the coming two years before the IAU GA in Vienna. The Event Horizon Telescope will complete first observations together with the beam-formed ALMA telescope in early 2017, and further observations can be expected in early 2018. The space-VLBI mission RadioAstron will have completed a large part of its key science programs in 2018 and will be at the zenith of its scientific exploitation. The continued GMVA operations will expand the large database of 3 mm and 7 mm VLBI observations focusing on studies of the major AGN in coordination with Fermi/LAT observations, and complemented by pioneering observations with the Event Horizon Telescope at 1 mm and the long-term imaging monitoring program MOJAVE at 2 cm wavelengths. In the next two years, GAIA will follow up on its first data release, establishing a unique astrometric database which will be matched against the international celestial reference frame provided by VLBI astrometric/geodetic observations. The VLTI instruments GRAVITY and MATISSE will substantially improve the fidelity of narrow angle astrometry and interferometric imaging, addressing a number of topics in studies of stars, exoplanets, and supermassive black holes.
The symposium proposed for 2018 is a very timely opportunity to provide an international forum for presenting and discussing the new results from all these fields and to share them with the broader astronomical community.