TIME : Friday, 15th February 2008 at 3:00 pm
PLACE : CSO Conference Room
SPEAKER : Dr. Attila Kovacs (Max Planck Institute for Radio Astronomy)
TITLE : Extragalactic
Science with APEX and SHARCII/CSO
ABSTRACT:
I will provide a brief overview of the extragalactic science projects
currently under
way at the APEX telescope in Chile, with special focus on the early
extragalactic
results from the new 295-pixel bolometer camera LABOCA. In
the second part,
for a more local flavor, I will present the results from a follow-up
study of submillimeter
galaxies with the SHARCII camera at the CSO. The SHARCII data allows
the first
firm constraints of the dust-temperatures and bolometric luminosities
for this population
of high-z galaxies. They also allow the testing of the radio to
far-infrared correlation
at the higher redshifts.
TIME : Monday, 28th April 2008 at 11:00 am
PLACE : CSO Conference Room
SPEAKER : Dr. Andrew Blain (California Institute of Technology)
TITLE : Evolution and
Astrophysics of Distant Ultraluminous Galaxies
ABSTRACT:
The most luminous high-redshift galaxies are dominated by energy
production at far-infrared wavelengths. Selected with poor
angular
resolution using ground-based submillimeter and space-borne far-
infrared telescopes, they are a crucial component of our
understanding
of galaxy formation. However, understanding their properties
requires
arduous follow-up observations from radio to X-ray. I will
describe
progress with understanding the evolution and astrophysics of
these
galaxies, which trace the top end of the galaxy luminosity
function,
and highlight some forthcoming opportunities using NASA's WISE,
and
ALMA.
TIME : Friday, 18th July 2008 at 3:00 pm
PLACE : CSO Conference Room
SPEAKER : Dr. Darek Lis (California Institute of Technology)
TITLE : Hydrogen
Isocyanide in the ISM and Comets
ABSTRACT:
I discuss the current understanding of the origin of hydrogen
isocyanide in the interstellar medium and comets. HNC, first detected
in comet Hyakutake by means of submillimeter spectroscopy, has now
been observed in a dozen moderately bright comets, not including the
very active comets Hale-Bopp and McNaught. The existing data suggest
that HNC production has to be efficient in the inner coma, just as the
material leaves the nucleus. The process has to be temperature
dependent to explain the observed variation in the HNC/HCN abundance
ratio with the heliocentric distance. Thermal degradation of
macromolecules or polymers produced from ammonia and carbon compounds,
such as acetylene, methane, or ethane appears to be a process
consistent with the existing observational data, including the very
low HNC/HCN ratio measured recently in comet 73P/Schwassmann-
Wachmann 3.
TIME : Monday, 1st December 2008 at 11:00 am
PLACE : CSO Conference Room
SPEAKER : Dr. Thomas Nikola (The Cornell University)
TITLE : ZEUS on the CSO: Probing the Gas
in Active Regions in ULIRGs and High-Redshift Galaxies
ABSTRACT:
The star formation rate per unit volume shows strong evolution over the
history of
the Universe. This suggests a change of the gas properties in
star formation regions or
a variation of their size or both. We have built a grating
spectrometer, ZEUS, for the
submillimeter wavelength regime to investigate the physical properties
of the gas in
regions of enhanced star formation in ULIRGs and distant
galaxies. With our instrument
we observe redshifted far-infrared fine structure lines, especially the
158 micron [CII] line,
mid-J CO lines, and the [CI] 371 micron fine structure line to trace
the gas properties in
the star forming regions. In this presentation I will introduce
our grating spectrometer,
ZEUS, and give an overview of the results that we have obtained using
our instrument
on the CSO.
TIME : Monday, 8th December 2008 at 11:00 am
PLACE : CSO Conference Room
SPEAKER : Professor Martin Houde (The University of Western Ontario)
TITLE : Observational Determination of the
Turbulent Ambipolar Diffusion Scale in Molecular Clouds
ABSTRACT:
I will present a study of the turbulent velocity dispersion spectra
(versus length
scale) for the coexistent HCN and HCO+ molecular species in the M17
star-forming
molecular cloud. I will show that the observed downward shift of the
ion's spectrum
relative to that of the neutral is readily explained by the existence
of an ambipolar
diffusion scale below which the motions of the ion and neutral
components of the
gas decouple from one another. For M17, this decoupling scale is
measured to be
1.8 mpc; this is the first time that this fundamental quantity is
determined observationally.
Moreover, this result is in excellent agreement with previous
theoretical predictions.
I will also demonstrate how these observations can be used to estimate
the strength of
the plane-of-the-sky component of the embedded magnetic field in a
completely novel way.
last updated on 2008/11/19 by hs