Distribution of Mass in the Milky Way Galaxy

Description and AimOur Galaxy has a special place in astronomy. We all feel a personal attachment to our home --- the Milky Way. Our galaxy is also unique because we have so much information about it, which we cannot get for any other galaxy. Observational results obtained during the lastdecade can be used to improve our understanding of the nature of the Milky Way.  New data from the SDSS and RAVE projects resulted in accurate estimates of the structure of the disk, of the escape velocity of the MW, of the distribution and the number of satellite galaxies. New measurements of proper motions of the LMC, and observations of High Velocity Stars put tight constraints on the models of the Milky Way. Theoretical models were also gradually improving. Substantial effort was put into more sophisticated mass modeling of the Milky Way, into more realistic N-body and hydro-dynamical models. The LCDM model became de facto the cosmological model. Its progress on explaining the large-scale structure of the Universe is very impressive. Yet its predictions on the small scale has been often criticized.  The Milky Way presents one of the tightest systems to constrain CDM, given the details of data ranging from individual radial velocities to proper motions, to the number of satellites and to microlensing. The orbit of the Sgr galaxy has also been particularly constraining. Is the CDM halo still consistent with observational data? What is the size and mass of our Galaxy? How many satellites do we have? What is the global distribution of stellar mass, gas, and dark matter in the Milky Way? We plan to address these and other related questions during the workshop. We'd like to bring together observers and CDM experts, dynamicists and simulators, experts, who spent years studying the nature of the Milky Way, and young scientists, who may find the subject worth spending their life on. The conference will be truly cross-discipline becausethe Milky Way is in the focus of research of many diverse fields of astronomy: origin of galaxies and cosmology, stellar and galactic dynamics, interstellar medium, stellar evolution, numerical modeling. Lorentz Center is an ideal location since we hope to have an environment, which encourages interactions and, at the same time, allows in-depth coverage of complicated issues related with the structure and origin of Our Galaxy.  Scientific Organizing Committee:A. Klypin               New Mexico State University HS. Zhao              St. Andrews UniversityJ. Binney               Oxford UniversityL. Blitz                   Berkeley UniversityA.G.A. Brown       Leiden University Outline of the programWe plan to have a five-day workshop (13--17 July 2009) with most of the time devoted to oral presentations and discussions. A preliminary list of topics is given below. We expect to host 50-60 participants.  Most of the talks will be 30~min long (25~min presentation plus 5 min discussion) with few shorter (15~min) presentations. We also reserve time for long discussions. There are no invited speakers and no review talks. A 30~min talk is long enough to give a short review, present results, and have a discussion.  For each talk we reserve 5~min for discussion. Sessions are organized in 1.5-2~hr blocks with breaks for coffee and lunch.  Each session is devoted to a specific issue with observational and theoretical talks intertwined. We do not respect seniority: a long talk is given to a student or postdoc, if there is enough interest in his/her results. Every day we plan to have two discussion sessions in the afternoon. Depending on the consensus and on the situation (material covered in previous talks, disagreements between different groups and so on) we may either have a common discussion for the whole workshop or split into smaller groups. This gives large fraction of afternoons to interactions and discussions. At the same time, most of the participants will be able to give oral presentation of their work. List of topics:- Mass modeling of the Milky Way: new methods and results - SDSS: mass distribution of stellar component - Velocities of stars in outer regions of the MW - Satellites: abundance and spatial distribution; dynamics and limitations on mass - RAVE: results on disk structure; constraints on the escape velocity- Formation of the Milky Way - Hydro+N-body models of MW - Simulations of bars: dynamics of the central region of MW- Bulge: gas and stellar kinematics and their constraints.- Microlensing counts and the amount of baryons and the dark matter in the central region - Gas in the Milky Way: hot corona; missing baryons? - SgrA* proper motion - LMC/SMC proper motion: Stream formation and mass of MW - Prospects of getting dark matter annihilation signal - Prospects of getting proper motions of faint SDSS halo streams