Daily Report #4794

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 Auroras

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)