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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-1287
DTSTART:20081028T203000Z
DURATION:PT1H0M0S
DTSTAMP:20260415T200841Z
LAST-MODIFIED:20080919T172122Z
LOCATION:6515 Sterling Hall
SUMMARY:Understanding the Interstellar Neighborhood: Structure\, Dynam
 ics\, and Quasar Scintillation"\, Astronomy Colloquium\, Dr. Jeff Lins
 ky\, UC- Boulder
DESCRIPTION:Absortion line spectroscopy provides a precise tool for un
 derstanding the properties of gas in the very local region of the Gala
 ctic disk and by implication interstellar media elsewhere in the unive
 rse. I will describe our recent studies of the dynamics and structure 
 of local warm gas based on high-resolution HST and ground based Ca II 
 spectra. Analysis of 157 sight lines shows that most velocity componen
 ts can be modeled with 15 velocity vectors indicating the presence of 
 15 parcels of warm gas located within a few parsecs of the Sun. Cloud-
 cloud interactions may explain the morphologies and physical propertie
 s of these clouds.<br><br>
\nLarge-amplitude intraday and annual varia
 bility of quasars can be simply explained as scintillation produced by
  nearby turbulent-scattering screens.<br><br>
\nI will show that the s
 cattering screens are located near the edges of nearby warm clouds and
  that the turbulence responsible for the scattering could be explained
  by the interaction of clouds with large differences in radial and tra
 nsverse velocities.
URL:https://www.physics.wisc.edu/events/?id=1287
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