HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4794
PERIOD COVERED: 5am February 18 - 5am February 19, 2009
(DOY
049/1000z-050/1000z)
OBSERVATIONS SCHEDULED
ACS/SBC 11984
Observing Saturn's High Latitude Polar
Planetary auroral emissions are critical indicators of how
the
magnetospheres of the planets work. Recently, a new
component of
Saturn's auroral emissions, i.e. high latitude auroras
inside the main
auroral oval, have been observed by the Cassini spacecraft
during
otherwise quiet auroral conditions. Such high latitude
auroras are of
immense interest since they occur on magnetic flux tubes
connected to a
region that is key to the overall dynamics of the system,
the
magnetotail, and where if conventional theories regarding
Saturn's
magnetosphere are correct there should not be any auroras.
These faint
auroral emissions have not been previously observed by the
Hubble Space
Telescope (HST). However, the unique oblique viewing
geometry afforded
during early 2009 due to Saturn's orbital longitude will
result in the
apparent brightening of these polar emissions due to the
limb-brightening effect, with the result that they may be
observable by
HST for the first ever time. In addition, at this time the
Cassini
spacecraft will be in a high latitude orbit, with a
trajectory that will
take it through these magnetic flux tubes, providing
essential
simultaneous in situ data. This is the last time Cassini
will be in such
an orbit during its mission as currently scheduled and HST
is the only
instrument capable of obtaining sustained long-term
observations of
Saturn's auroras. These observations will address the
following:
Does Saturn exhibit high latitude UV auroras observable by
HST? Where do
these auroras occur, and at what altitude? How do these
auroras behave
over time? How variable are they? Are they periodic? How do
they behave
with respect to other auroral components? What processes
drive these
auroras?
Are these auroras generated by processes internal to the
magnetosphere
or are they driven by the solar wind? How do the infrared
(IR) auroras
relate to the ultraviolet (UV) auroras?
WFPC2 11797
Supplemental WFPC2 CYCLE 16 Intflat Linearity Check and
Filter Rotation
Anomaly Monitor
Supplemental observations to 11029, to cover period from
Aug 08 to SM4.
Intflat observations will be taken to provide a linearity
check: the
linearity test consists of a series of intflats in F555W,
in each gain
and each shutter. A combination of intflats, visflats, and
earthflats
will be used to check the repeatability of filter wheel
motions.
(Intflat sequences tied to decons, visits 1-18 in prop
10363, have been
moved to the cycle 15 decon proposal 11022 for easier
scheduling.)
Note: long-exposure WFPC2 intflats must be scheduled
during ACS anneals
to prevent stray light from the WFPC2 lamps from
contaminating long ACS
external exposures.
Note: These are supplemental observations to cover June to
SM4 (Oct 8
'08) + 6
months.
WFPC2 11944
Binaries at the Extremes of the H-R Diagram
We propose to use HST/Fine Guidance Sensor 1r to survey
for binaries
among some of the most massive, least massive, and oldest
stars in our
part of the Galaxy. FGS allows us to spatially resolve
binary systems
that are too faint to observe using ground-based, speckle
or optical
long baseline interferometry, and too close to resolve
with AO. We
propose a SNAP-style program of single orbit FGS TRANS
mode observations
of very massive stars in the cluster NGC 3603, luminous
blue variables,
nearby low mass main sequence stars, cool subdwarf stars,
and white
dwarfs. These observations will help us to (1) identify
systems suitable
for follow up studies for mass determination, (2) study
the role of
binaries in stellar birth and in advanced evolutionary
states, (3)
explore the fundamental properties of stars near the main
sequence-brown
dwarf boundary, (4) understand the role of binaries for
X-ray bright
systems, (5) find binaries among ancient and nearby
subdwarf stars, and
(6) help calibrate the white dwarf mass - radius relation.
WFPC2 11978
Luminous and Dark Matter in Disk Galaxies from Strong
Lensing and
Stellar Kinematics
The formation of realistic disk galaxies within the LCDM
paradigm is
still an unsolved problem. Theory is only now beginning to
make
predictions for how dark matter halos respond to galaxy
formation and
for the properties of disk galaxies. Measuring the density
profiles of
dark matter halos on galaxy scales is therefore a strong
test for the
standard paradigm of galaxy formation, offering great
potential for
discovery. However, from an observational point of view,
the degeneracy
between the stellar and dark matter contributions to
galaxy rotation
curves remains a major road block. Strong gravitational
lensing, when
coupled to spatially-resolved kinematics and stellar
population models,
can solve this long-standing problem. Unfortunately, this
joint
methodology could not be exploited so far due to the
paucity of known
edge-on spiral lenses. Exploiting the full SDSS-DR7
archive we have
identified a new sample of exactly these systems. We
propose multi-color
HST imaging to confirm and measure a sample of twenty
spiral lenses,
covering a range of bulge to disk ratios. By combining
dynamical lensing
and stellar population information for this unique sample
we will
deliver the first statistical constraints on halos and
disk properties,
and a new stringent test of disk galaxy formation
theories.
WFPC2 11989
The Integral Sign Galaxy
We will observe the unusual warped disk galaxy known as
the Integral
Sign Galaxy, UGC 3697, with a small two-position WFPC2
mosaic.
Observations will be obtained in three broad band filters
and the
resulting image will be released on the 19th anniversary
of the launch
of the Hubble Space Telescope on ~April 24, 2009.
Multidrizzled mosaics
will be made available through the archive.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11684 - REAcq (2,1,2) failed to RGA Hold due to (QF2STOPF)
stop flag on
FGS-2 @ 049/1523z
Observations affected: WFPC Proposal ID# 11978 observations 85-88.
11685 - REAcq (1,3,3) failed to RGA Hold due to (QF1STOPF)
flag on FGS-1 @
049/1908z
Observations affected: WFPC Proposal ID# 11989, observations 91 & 92.
11686 - REAcq (1,3,3) fails to Gyro Control, V1 error was
too large to
correct @ 049/2121z
Observations affected: WFPC Proposal ID# 11989, observations 93 & 94.
11687 - REAcq (1,3,3) failed to RGA Hold due to (QF1STOPF)
flag on FGS-1 @
049/2200z
Observations affected: WFPC Proposal ID# 11989, observations 95 & 96.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
06
06
FGS
REacq
08
04
OBAD with Maneuver
28
28
SIGNIFICANT EVENTS: (None)