Astro Seminar: "ALMA observations of strongly lensed galaxies: A window into the small-scale structure of dark matter halos"

Wed, 04/01/2015 - 14:00 - 16:00
Yashar Hezaveh (Stanford)

ALMA is starting to open a new window into the dusty structures of
the universe. With its milli-arcsec resolution and spectral
capabilities, among other things, it is promising to teach us
invaluable lessons about super massive black holes, planet formation,
dark matter, and the birth of first galaxies.  In this talk, I will
discuss ALMA observations of strongly lensed galaxies and show how we
can detect low-mass dark matter subhalos in the lensing galaxies by
measuring the gravitationally-induced distortions of the lensed
images of background sources. The number of observed low-mass
satellites of the Milky Way is about three orders of magnitude lower
than what cold dark matter (CDM) simulations predict, an issue that
is referred to as the "Missing Satellite Problem". By measuring the
abundance of dark matter subhalos in the halos of the lensing
galaxies we can determine the mass function of the dark matter
subhalos (measured using a purely gravitational probe) and compare it
with the CDM predictions. I will give a brief overview of our
observational campaign to use ALMA and this population of strongly
lensed sub-millimeter galaxies to resolve this puzzle. 

David Rittenhouse Laboratory A6