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NRAO/Socorro Colloquium Series

Nikta Amiri

University of Colorado

The Proper Motion of the Andromeda Galaxy

The proper motion of the Andromeda galaxy is important to study the future (and past) dynamical evolution of the Local Group. I explain our long-term project awarded for performing astrometric monitoring of galactic analog masers in M31 with the Very Long Baseline Array. We want to refine, assess, and independently verify the claimed proper motion and geometric distance measurements of M31. We also want to get a good distance comparable to but independent of other methods (e.g. using detached eclipsing binaries and Cepheids). We expect to measure the proper motion of M31 as well as its geometric distance via rotational parallax with an unprecedented accuracy of ~10 micro arc sec per year over a time scale of a few years. We have detected and confirmed five water maser complexes in M31 using the Green Bank Telescope. The masers are distributed around the molecular ring, including locations close to the major and minor axes, which is nearly ideal for proper motion studies. The five water masers detected in M31 were selected from a sample of bright 24 micron sources associated with dusty molecular clouds and presumably HII regions. I will discuss the properties of maser emitting regions in M31 by analyzing Hershcel, 24 micron Spitzer, and H-alpha maps.


October 25, 2013
11:00 am

Array Operations Center Auditorium

All NRAO employees are invited to attend via video, available in Charlottesville Room 230, Green Bank Room 137 and Tucson N525.

Local Host:: Mark Claussen

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