CMZ image

SMA CMZ Survey

The SMA Legacy Survey of the CMZ is the first sub-pc scale survey of the largest reservoir of dense, molecular gas in our Galaxy, the Central Molecular Zone (CMZ, the inner 500 pc of the Milky Way). Analogous to some high-redshift galaxies in global properties (kinematics, baryonic composition, and density), the CMZ provides our nearest laboratory to understand extreme star formation throughout the universe.

Over the course of 3 years, we will map 240 sq. arcminutes of the highest column density structure in the CMZ at 0.2 pc resolution at 230 GHz, tracing both cold dust continuum and a multitude of molecular line transitions including CO isotopologues and tracers of dense gas, hot cores, and shocks/outflows. We will identify the location of dense pre-stellar cores in the CMZ, characterize their physical properties, and search for embedded signatures of star formation. These measurements allow us to address fundamental questions regarding the nature of star formation in extreme environments as well as the current state and potential episodicity of star formation in the CMZ. We completed year 2 of the survey in Summer 2015, and expect to complete the full survey in Summer 2016.

The main science questions motivating the survey are:

  1. What is the cause of the extremely low star formation efficiency (given the reservoir of dense gas)
    in the CMZ?
  2. Is there an energy and star formation cycle in the CMZ? Where does gas enter the CMZ?
  3. Is SF induced by tidal compression by SgrA*?
  4. Can we find precursors to the most massive stars in the Galaxy?

The survey will allow for: (i) a complete census of the most massive and dense cloud cores; (ii) the location, strength and nature of strong shocks; (iii) the relationship of star formation to environmental conditions such as density, shocks, and large-scale flows.

The Central Molecular Zone (CMZ) shown as a three-color image. Red - Column density of molecular Hydrogen, N(H2), derived from Herschel in Battersby et al. (in prep.), Green - 70 μm emission from Hi-GAL, Blue - 8 μm emission from GLIMPSE. The white contours show the approximate coverage area of the SMA Legacy Survey of the CMZ.

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