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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-7969
DTSTART:20221020T203000Z
DTEND:20221020T213000Z
DTSTAMP:20260414T153807Z
LAST-MODIFIED:20221013T204906Z
LOCATION:Sterling Hall 4421
SUMMARY:Towards precision measurements of dark matter\, Astronomy Coll
 oquium\, Sukanya Chakrabarti\, University of Alabama\, Huntsville
DESCRIPTION:For more than a century now\, our inference of the mass di
 stributions (including dark matter) in galaxies has been based on mode
 ling the positions and velocities of stars\, i.e.\, using kinematic an
 alyses\, which assume equilibrium. These kinematic estimates can be in
 accurate for a time-dependent potential\, and there are now many lines
  of observational evidence that show that our Galaxy has had a highly 
 dynamic history. Recent technological advances now make it possible fo
 r us to carry out extreme-precision time-series measurements of the ac
 celeration of stars that live within the gravitational potential of ou
 r Galaxy. I will talk about several different methods of direct accele
 ration measurements that we have developed\, including our recent anal
 ysis of compiled pulsar timing data from which we were able to measure
  the Galactic acceleration for the first time. Given the measured acce
 leration\, we can straightforwardly use the Poisson equation to determ
 ine the total density\, and the local dark matter density (given an ac
 counting of the stellar density). There are testable differences betwe
 en popular models of dark matter on small scales\, i.e.\, in their sub
 -structure. I will discuss the potential for measuring dark matter sub
 -structure in the Milky Way with pulsar timing and eclipse timing\, an
 d for constraining theories of gravity by combining constraints from p
 ulsar timing and extreme precision radial velocity measurements. I wil
 l end by discussing our recent work in developing an “acceleration l
 adder” by calibrating kinematic estimates of the acceleration to dir
 ect acceleration measurements.
URL:https://www.physics.wisc.edu/events/?id=7969
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