Letters of Intent received in 2015

LoI 2017-270
Astrophysical Masers: Unlocking the Mysteries of the Universe

Topics

1) The Cosmic Distance Scale and the Hubble Constant
a) megamasers
b) rotational parallaxes

2) The Structure of the Milky Way
a) parallaxes and proper motions of star forming regions

3) Local Group Cosmology: Its History and Fate
a) galaxy proper motions

4) Black Hole Masses and the M-sigma relation
a) Resolved kinematics within BH sphere of influence

5) The Formation of Massive Stars
a) dynamics of gas within 100 AU of a YSO

6) Pulsation and Outflows in Evolved Stars
a) parallaxes and proper motions

7) Theory of masers and maser sources

Rationale

Astronomical masers touch on a vary broad range of astrophysical phenomena. Originally, maser research concentrated on star formation and evolved stars, where the high resolution afforded by bright maser emission allowed one to probe dynamics on ~1 AU scale with ~ 1 km/s motion accuracies. A couple of decades ago, the discovery of water masers from accretion disks around super-massive black holes,
opened new avenues to resolve the disks, measure motions, and estimate supermassive black hole masses and distances to galaxies geometrically.

Over the past twenty years, there have been meetings focussing on masers spaced by roughly 5 years. The last meeting devoted to masers was in 2012 in South Africa. Since then there has been an explosion of work on masers, especially related to the cosmic distance scale, the structure of the Milky Way, and the masses of (AGN) black holes. In particular, maser astrometry has achieved parallax accuracies better than 10 micro-arcseconds, comparable to that hoped for from Gaia. This fantastic development has led to surveys to map the Galaxy and to the prospect of measuring the Hubble Constant with better than 3% accuracy, directly and independently of all other methods.

While the main focus of the Symposium is on cosmic masers, in order to broaden the impact of the Symposium, we intend also to invite speakers from outside the maser science community who work on similar topics as those listed above. In particular, the results reached using masers on the structure of the Milky Way and the cosmological distance scale will be compared with those obtained using other methods (e.g., by the GAIA mission and Cepheids and gravitational lensing). We also plan to have theoretical reviews of forefront questions for the major science topics, including the cosmic distance scale, galactic structure, star formation and evolved stars.

We propose Sardinia, Italy for the next maser symposium, since there is an active community of Italian scientists involved in many aspects of maser science. In particular, the island of Sardinia hosts one of the largest radio telescope in Europe, the 64-m Sardinia Radio Telescope (SRT). This telescope was recently commissioned and will be heavily involved in maser-related projects, both as single-dish and in VLBI networks. The date for the meeting, September 2017, is also timely, coming almost 6 years after the last maser conference. Not only have there been major developments in maser research over that period (e.g., those related to the BeSSeL Survey and the Megamaser Cosmology Project to name two), we expect further growth of the field as new facilities come on line. Indeed, ALMA is operating at almost full capacity (including the commissioning of band 5, particularly relevant for water maser observations in the mm regime). The upgraded JVLA and eMERLIN, as well as the KVN and VERA VLBI arrays, are now also regularly delivering excellent results. Therefore, we anticipate talks that report on ALMA and JVLA studies of continuum emission and thermal molecular line emission toward maser sources. In addition, the scientific community is in the process of discussing the key science goals for the SKA, and some results are already being
reported by its pathfinders in Australia (ASKAP) and South Africa (MeerKAT).

Clearly, the proposed meeting will offer the opportunity to discuss advances in observation and theory and to plan challenging programs in maser science that will tackle fundamental scientific questions of the next decade.

Additional notes:
- presently, the list of SOC members is in an advanced stage of composition and, as requested, will be reported in the Full Proposal. A balance in gender, geographic, and scientific diversity has been, indeed, taken into account.
- together with the reported coordinating and other divisions list, we would also like to mention the relevance of the meeting for the following IAU commissions (not available in the drop-down menu in the LoI electronic form):
IAU Commissions:
C.B4 ''Radio Astronomy"
C.A1 ''Astrometry"
C.G4 ''Pulsating Stars"