BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-1954 DTSTART:20100916T203000Z DTEND:20100916T220000Z DTSTAMP:20260422T144425Z LAST-MODIFIED:20100913T154849Z LOCATION:4421 Sterling Hall Same Location SUMMARY:Finding Dark Galaxies From Their Tidal Imprints\, Astronomy Co lloquium\, Sukanya Chakrabarti\, UC Berkeley DESCRIPTION:Characterizing the ubiquitous dark matter in the universe has proven to be one of the most challenging problems in modern astrop hysics. If the dynamical impact of dark-matter dominated dwarf galaxie s on the outskirts of galactic disks can be deciphered\, we may be abl e to infer and characterize cold dark matter sub-structure in a fundam entally new way. I show how one can analyze observed disturbances in t he outer gas disks of spiral galaxies to quantitatively characterize g alactic companions without requiring knowledge of their optical light. This method\, which I call "Tidal Analysis"\, allows one to determine the mass and relative position (in radius and azimuth) of galactic co mpanions from analysis of observed disturbances in gas disks. I will f irst demonstrate the validity of this method by applying it to local s pirals with known optical companions to provide a proof of principle. I will then review my earlier work on the Milky Way that prompted the development of this method. Specifically\, analysis of observed distur bances on the outskirts of the Milky Way disk favor a 1:100 mass ratio perturber with a close pericentric approach. I will conclude by discu ssing ongoing work on developing scaling relations between observed HI maps and satellite mass\, and our plans for the near-future which inc lude testing the Tidal Analysis method on large samples to determine i ts statistical viability.
\n URL:https://www.physics.wisc.edu/events/?id=1954 END:VEVENT END:VCALENDAR