Star Formation in Nearby Galaxies

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Star Formation in Nearby Galaxies

• Working Notes (June 14, 2007)
• Draft Abstract
• Current Exposure Time Calculations
• Open Issues

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Draft Abstract - old version
Star formation is one of the most fundamental
processes in astronomy, controlling a range of
phenomena from the evolution of galaxies to the
formation of planetary systems. The WFC3 is an
ideal instrument for studying star formation
since it is optimized in both the UV and the IR -
critical wavelength ranges for unraveling the
physics of star formation. The extensive array of
narrow-band filters is also important, providing
measurements of shock fronts and gas pressure.
Hence, the WFC3 Science Oversight Committee (SOC)
proposes to make an \bf integrated attack on the
problem of star formation by obtaining extensive
datasets for a small sample of nearby star
formation regions. The target galaxies will
include 30 Doradus (nearest major super star
cluster), M82 (nearest starburst galaxy), Cen A
(nearest elliptical) as well as \approx six
other galaxies designed to cover a range of
environments from low surface brightness to
starbursts. Broad-band imaging from the UV to IR
will be used to study stellar populations, ages,
metalicities and dust extinction. Narrow-band
imaging will be used to measure local star
formation rates, gas pressure, and shock
morphologies. Our primary science questions are
1) How does star formation, and its history,
vary amongst galaxies of different types ? 2)
What triggers and regulates star formation ? 3)
How universal is the Initial Mass Function?
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Draft Abstract- June 15 version -
Star formation is a fundamental astrophysical
process it controls phenomena ranging from the
evolution of galaxies and nucleosynthesis to the
origins of planetary systems and abodes for life.
?The WFC3,optimized at both UV and IR
wavelengths, and equipped with an extensive array
of narrow-band filters, brings unique
capabilities to this area of study. The WFC3
Scientific Oversight Committee (SOC) proposes an
itintegrated program/ on star formation in
the nearby universe which will fully exploit
these new abilities.Our targets range from the
well-resolved 30 Doradus in the LMC (the nearest
super star cluster) and M82 (the nearest
starbursting galaxy) to about half a dozen other
nearby galaxies that sample a wide range of
star-formation rates and environments. Our
program consists of broad-band multiwavelength
imaging over the entire range from the UV to the
near-IR, aimed at studying the ages and
metallicities of stellar populations, revealing
young stars that are still hidden by dust at
optical wavelengths, and showing the integrated
properties of star clusters. Narrow-band imaging
of the same environments will allow us to measure
star-formation rates, gas pressure, chemical
abundances,extinction, and shock morphologies.
The primary scientific issues to be addressed
are (1) What triggers star formation? (2) How do
the properties of star-forming regions vary among
different types of galaxies and environments of
different gas densities and compositions? (3) How
do these different environments affect the time
history of star formation? (4) Does the stellar
initial mass function depend on metallicity or
other environmental factors?
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CANDIDATE TARGETS - Nearby galaxies with wide
range of properties (e.g., Hubble types,
giants/dwarfs, gas-rich/gas-poor, starbursts/low
star formation) (m-M)
Type 31.0 NGC 4382
- SO in Virgo (star formation)
S0 31.0 NGC 4150 - SO in Virgo (star
formation) S0 30.0 NGC
4592 - retarded galaxy
spiral 29.9 NGC 2841 -
flocculent spiral
spiral 28.6 Cen A - nearest
elliptical (accretion) elliptical 28.6
M 83 - grand-design spiral
spiral 27.9 NGC 4214 -
dwarf
irregular 26.9 M 82 - dusty
starburst
irregular 18.5 30 Dor - 105 Msolar
star cluster star cluster 13.9 NGC 3603
- 104 Msolar star cluster star
cluster
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Current Orbit Calculations - old version
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Current Orbit Calculations - June 15 version