MSV-2035 Astronomy Document - Inside Design - FINAL - FINAL

with ɅCDM model which predicts hierarchical formation of the Galaxy due to mergers. Wide-field imaging surveys have discovered several streams, and more such streams are expected to be discovered with the LSST. Stellar streams provide a snapshot of Milky Way stellar halo formation and improve our understanding of its fundamental building blocks. To piece together the puzzle of the Galactic structure and how it evolved is one of the fundamental questions in astronomy. In addition, what is the shape of dark matter potential of the Milky Way? What is the origin and nature of high velocity clouds (HVCs) in the MilkyWay and local galaxies? How many satellite galaxies are there in the Milky Way, and what are their star formation and chemical enrichment histories? These are other unanswered questions that can be addressed through detailed observational data as well as theory and simulations. The Galactic centre presents a unique opportunity to study supermassive black holes in the centres of galaxies and their roles in the formation and evolution of galaxies. High angular resolution observations with the 10-meter class telescopes in the past couple of decades, in the infrared, using adaptive optics and interferometric techniques, have enabled accurate determination of the proper motion of stars within 0.04 pc of Sgr A* (associated with the Galactic centre), and provided the first test of General Relativity around a supermassive black hole. The first ever image of the central black hole Sgr A* in the millimeter by the Event Horizon Telescope provides new insights into accretion, outflow, and gravitational physics at unprecedented scales. Facilities of the future, such as the extremely large telescopes (EELT, TMT, GMT) will enable observations with higher spatial resolutions than currently possible that will enable detection and mapping of the orbits of stars much closer to the centre (Sgr A*), and much fainter. Measurements of the orbits of stars closer to the centre will enable measurement of the precession of the periapse and test the specificmetric formof General Relativity, probe the distribution of dark stellar remnants and dark matter around black hole and test the models of galaxy evolution and dynamics. Such observations will supplement theoretical studies and provide a great fillip to black hole science. Astronomy & Astrophysics 16 Figure 1: The orbit of stars within the central 1.0 X 1.0 arcsec region of the Milky Way Galaxy. (Figure credit: UCLA Galactic Center Group - W.M. Keck Observatory Laser Team) MEGA SCIENCE VISION-2035