Powerpoint template for scientific posters Swarthmore College

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Star Formation Research Now With
ALMA Debra ShepherdNational Radio Astronomy
Observatory
ALMA Specifications Todays (sub)millimeter
interferometers are becoming more powerful yet
ALMA will surpass them all by 2012
Parts of this research made possible by the
Origins Institute
McMaster University
Current Capabilities
With the Atacama Large Millimeter Array (ALMA)
Obtain full census of star formation cloud
properties in dense filaments, not just small
area.
Color image of the G34 massive star forming
cluster from the Spitzer GLIMPSE survey. G34.26
illustrates the formation of an O star (20Mo)
while the UC HII region and G34.4 MM shows a site
forming only early B stars along a dense filament
of gas.
Inset shows red- and blue-shifted CO(1-0)
emission made with the Owens Valley Millimeter
Array. Each of the two mosaiced fields has
roughly 9 hours on source integration time takin
in multiple array configurations.
Dynamics of ionized gas in RRLs, protostars (O
star(s) forming cluster) in mm continuum,
shocks gas in molecular lines. ELVA to map
free-free continuum RRLs at cm ls
RMS 60 mJy/beam in channels with 1.3 km/s
resolution. Spatial resolution 3.5 (13,600
AU at D 3.9 kpc). Extended emission resolved
out so relationship between the outflows and gas
in extended filaments cannot be obtained at
similar resolutions. Only the most massive
flows and cores can be detected at this distance
of 3.9 kpc
1.4 pc
ALMA will be able to image entire structures, and
recover all size scales relate outflows and
embedded sources to larger scale structure and
kinematics observed at the same resolution.
Matched resolution with EVLA. Not easy at first!
Study triggered star formation along SNR shocks
as well as the shock dynamics in RRLs and
molecular lines.
Show spectrum below a sample ALMA Band 6
spectrum taken on the SMT (Ziurys, et al.)
Ionized flow from early B protostar (pre-MS, 104
years old) no UC HII region created yet.
ALMA pre-production band 6 (1mm) spectrum taken
at the SMT (Ziurys et al.) shows incredibly
complex spectra toward SgrB2 (N). Must develop
complex imaging analysis tools to deal with
information density!
These images represent very good VLA data of
free-free continuum emission from ionized outflow
gas toward forming, early B stars. Multiple
VLA configurations allow increased sensitivity to
low-level, complex structure. Resolution 0.3
(700 AU at D 2 kpc) RMS 30 mJy/beam 2-4
hours on-source integration time. No velocity
information.
Continuum?
ALMA will resolve the disk outflow interface with
many resolution elements while still recovering
extended emission the challenge will be to find
appropriate chemical species that trace different
parts of the disk and perhaps find adequate
continuum to develop good continuum image over
many GHz.
Observations model of 7mm continuum
Dynamics of ionized gas can be recovered with RRL
observations but only for strongest sources, will
likely need gt 8 hrs on-source integration
time Millimeter lines and continuum emission
cannot be obtained with similar resolution and
sensitivity.
Highest ALMA resolution at 300 GHz 1 mm
(0.015)
Jet escaping from UC HII region in G192.16 (young
B2 star, 105 years old)
100 AU 0.3 at d300pc
Highest ALMA resolution at 850 GHz
350 ?m