The QuaStar Survey: Detecting Hidden Low-velocity Gas in the Milky Way’s Circumgalactic Medium

  title={The QuaStar Survey: Detecting Hidden Low-velocity Gas in the Milky Way’s Circumgalactic Medium},
  author={Hannah V. Bish and Jessica K. Werk and Joshua E. G. Peek and Yong-gang Zheng and Mary E. Putman},
  journal={The Astrophysical Journal},
From our position embedded within the Milky Way’s interstellar medium, we have limited ability to detect gas at low relative velocities in the extended Galactic halo because those spectral lines are blended with much stronger signals from dense foreground gas. As a result, the content of the Milky Way’s circumgalactic medium (CGM) is poorly constrained at ∣v LSR∣ ≲150 km s−1. To overcome this complication, the QuaStar survey applies a spectral differencing technique using paired quasar−star… 

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