Description

Galactic astronomy is the study of our own Milky Way galaxy and all its contents. This is in contrast to extragalactic astronomy, which is the study of everything outside our galaxy, including all other galaxies.

The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek 'Galaxias', sometimes referred to simply as "the Galaxy"), is a barred spiral galaxy that is part of the Local Group of galaxies. Although the Milky Way is one of billions of galaxies in the observable universe, the Galaxy has special significance to humanity as it is the home galaxy of the planet Earth.

Galactic Structure and Kinematics - William van Altena

The field of astrometry has undergone a rebirth, as of late, and has once again assumed an influential role within many fields of astronomy. A new generation of astrometric instrumentation combined with ever-growing computing power is making possible significant improvements in the accuracy and sheer quantity of fundamental, astrometric data available. This wealth of quality data makes it possible to address questions of Galactic kinematics and stellar evolution that were heretofore intractable. A tradition of research in astrometry at Yale continues today.

Research interests in astrometry at Yale lie primarily in the fields of absolute and relative proper motions, stellar parallaxes, binaries, space astrometry, and instrumentation and techniques to improve the accuracy of astrometric observations with applications to star clusters and Galactic structure & kinematics. Some of our current research includes:

• Binary Stars:
  SIM grid
  Hipparcos suspected binaries
  Improvement of binary orbits
• Stellar parallaxes
• Galactic Structure:
  Solar motion
  Stellar streams
• Open Star Clusters:
  Memberships and internal motions
  Internal structure parameters
• Globular Star Clusters:
  Internal kinematics and distances
• Kinematics of the Local Group of Galaxies:
  Tangential velocities and orbits
• Astrometric Faint Reference System:
  Extension of the Hipparcos/ICRS to fainter magnitudes in the southern hemisphere

For this work, the following techniques are being extensively used:

• Absolute Proper Motions
• Relative Proper Motions
• Speckle interferometry
• Orthogonal Transfer CCD (OTCCD)
• Plate digitization

Some of this research is carried on using the following instrumentation and observing programs

• Yale Southern Observatory
• Southern Proper Motion Program