HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4789
PERIOD COVERED: 5am February 10 - 5am February 11, 2009
(DOY
041/1000z-042/1000z)
OBSERVATIONS SCHEDULED
WFPC2 11612
Eta Carinae's Continuing Instability and Recovery - the
2009 Event
Eta Carinae is the only really observable example of
structural recovery
from a massive giant eruption, a "supernova imposter'
event. Moreover it
is the only well-observed star above 100 Msun, and its
5.5-year-recurrent spectroscopic events provide
extraordinary clues to
its surface instability. This truly unique combination of
attributes
makes it valuable for understanding the most massive
stars. A fresh
development arose a few years ago: The star has brightened
much faster
than before, and appears to have entered a rapid stage in
its
post-eruption recovery.
A spectroscopic event will occur at 2009.0, soon after the
planned HST
servicing mission. Because of the recent secular trend,
this event is
expected to differ from its well-observed 2003.5
predecessor. The
differences will be very important, because they offer
clues to
very-massive-star structural instabilities that can't be
observed in any
other known way.
Some of the needed observations require HST's high spatial
resolution
and UV coverage. We propose an efficient, well-chosen set
of STIS and
ACS observations around the critical time. If the
servicing mission is
too late for the event, then a subset of the observations
will still be
merited.
WFPC2 11966
The Recent Star Formation History of SINGS Galaxies
The Spitzer Legacy project SINGS provided a unique view of
the current
state of star formation and dust in a sample of galaxies
of all Hubble
types. This multi-wavelength view allowed the team to
create current
star formation diagnostics that are independent of the
dust content and
increased our understanding of the dust in galaxies. Even
so, using the
SINGS data alone we can only make rough estimates of the
recent star
formation history of these galaxies. The lack of high
resolution
observations (especially U-band and H-alpha) means that it
is impossible
to estimate the ages of young clusters. In addition, the
low resolution
of the Spitzer and ground-based observations means that
what appear to
be individual Spitzer sources can actually be composed of
many
individual clusters with varying ages. We need to know the
ages, star
formation histories, and extinction of these individual
clusters to
understand how these clusters form and age and thus
influence the
evolution of the galaxy. In this proposal we address this
missing area
of SINGS by obtaining high-resolution WFPC2 UBVI &
H-alpha observations
to not only accurately locate and determine the ages of
the young
stellar clusters in the actively star forming SINGS
galaxies but to also
address a variety of other scientific issues. Over 500 HST
orbits and
500 hours of Spitzter observing time have been dedicated
to observations
of the SINGS sample. But the HST observations have not
been systematic.
By adding a relatively small fraction of this time for
these requested
observations, we will greatly enhance the legacy value of
the SINGS
observations by creating a uniform high resolution multi-wavelength
HST
archive that matches the quality of the lower resolution
SINGS archive.
WFPC2 11967
WFPC2 Imaging of the Lockman Hole
In order to understand galaxy evolution and constrain
theoretical
models, we require both multiwavelength photometry (to
robustly
determine physical parameters such as star formation rates
and stellar
masses) and detailed morphological information. Galaxy
morphology
encodes crucial information about galaxy formation history
and the
physical processes that trigger star formation and AGN
activity, and
high-resolution imaging for large samples of galaxies is
currently only
obtainable with HST. The Lockman Hole has been the target
of extensive
multi-wavelength observations from the X-ray to the radio,
and will be
the target of the deepest wide-area blankfield thermal IR
observations
with Herschel, but currently lacks comprehensive HST
imaging. We propose
to obtain WFPC2 imaging of ~500 arcmin2 of the central
region of the
Lockman Hole in F606W and F814W, to a depth of V606~26.8
and I814~26.
This imaging is crucial in order to characterize the
sources detected at
other wavelengths.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS: (None)
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
`
SCHEDULED SUCCESSFUL
FGS
GSacq
05
05
FGS REacq
09
09
OBAD with Maneuver
28
28
SIGNIFICANT EVENTS: (None)