HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4766
PERIOD COVERED: 5am January 6 - 5am January 7, 2009 (DOY
006/1000z-007/1000z)
OBSERVATIONS SCHEDULED
FGS 11789
An Astrometric Calibration of Population II Distance
Indicators
In 2002 HST produced a highly precise parallax for RR
Lyrae. That
measurement resulted in an absolute magnitude, M(V)=
0.61+/-0.11, a
useful result, judged by the over ten refereed citations
each year
since. It is, however, unsatisfactory to have the direct,
parallax-based, distance scale of Population II variables
based on a
single star. We propose, therefore, to obtain the
parallaxes of four
additional RR Lyrae stars and two Population II Cepheids,
or
stars. The Population II Cepheids lie with the RR Lyrae
stars on a
common K-band Period-Luminosity relation. Using these
parallaxes to
inform that relationship, we anticipate a zero-point error
of 0.04
magnitude. This result should greatly strengthen
confidence in the
Population II distance scale and increase our
understanding of RR Lyrae
star and Pop II Cepheid astrophysics.
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:
11631 - REAcq(1,2,1) scheduled at 006/13:13:44 and at
006/14:49:42 failed.
Initial GSACQ(1,2,1) at 006/11:47:12 was successful.
Observations affected: WFPC 50 to 53, proposal 11966.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
05
05
FGS
REacq
10
08
OBAD with Maneuver
28
28
SIGNIFICANT EVENTS: (None)