Daily Report #4955

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #4955

PERIOD COVERED: 5am October 20 - 5am October 21, 2009 (DOY293/09:00z-294/09:00z)

OBSERVATIONS SCHEDULED

FGS 11785

Trigonometric Calibration of the Distance Scale for Classical Novae

The distance scale for classical novae is important for understanding
the stellar physics of their thermonuclear runaways, their
contribution to Galactic nucleosynthesis, and their use as
extragalactic standard candles. Although it is known that there is a
relationship between their absolute magnitudes at maximum light and
their subsequent rates of decline--the well-known maximum-magnitude
rate-of-decline (MMRD) relation--it is difficult to set the zero-point
for the MMRD because of the very uncertain distances of Galactic
novae.

We propose to measure precise trigonometric parallaxes for the
quiescent remnants of the four nearest classical novae. We will use
the Fine Guidance Sensors, which are proven to be capable of measuring
parallaxes with errors of ~0.2 mas, well below what is possible from
the ground.

NIC 11417

NICMOS Detector Read noise and Dark Current

The NICMOS detector characteristics will be monitored during the
entire extent of the SMOV4 through a set of dark exposures. This will
also allow a determination of the detector temperature from bias
measurements. The data should be obtained in SAA-free orbits,
approximately every 24 hours. In addition, the detector read noise and
the detector shading profiles will be measured once a week.

NIC1/NIC2/NIC3 11820

NICMOS Post-SAA Calibration - CR Persistence Part 7

Internals for CR persistence

NIC2 11148

High Contrast Imaging of Dusty White Dwarfs

For the past 18 years, only one white dwarf with a circumstellar dust
disk was known to exist. In the last two years, six new disks have
been discovered. Since all material inwards of a few AU should be
scoured clean during post main sequence evolution, the primary
explanation is the presence of a planetary system that is perturbing
relic planetesimals into the tidal disruption radius of the white
dwarf. Dusty disks around white dwarfs should be markers for planets
and we propose to use high contrast imaging to search for faint
companions down to 6 M_$J$ that may be feeding the disks. White dwarfs
are uniquely suited for planet searches, where the planet/white dwarf
contrast is less than for main sequence stars.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to monitor the bias in the 1x1, 1x2,
2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up
high-S/N superbiases and track the evolution of hot columns.

STIS/MA1/MA2 11857

STIS Cycle 17 MAMA Dark Monitor

This proposal monitors the behavior of the dark current in each of the
MAMA detectors.

The basic monitor takes two 1380s ACCUM darks each week with each
detector. However, starting Oct 5, pairs are only included for weeks
that the LRP has external MAMA observations planned. The weekly pairs
of exposures for each detector are linked so that they are taken at
opposite ends of the same SAA free interval. This pairing of exposures
will make it easier to separate long and short term temporal
variability from temperature dependent changes.

For both detectors, additional blocks of exposures are taken once
every six months. These are groups of five 1314s FUV-MAMA Time-Tag
darks or five 3x315s NUV ACCUM darks distributed over a single
SAA-free interval. This will give more information on the brightness
of the FUV MAMA dark current as a function of the amount of time that
the HV has been on, and for the NUV MAMA will give a better measure of
the short term temperature dependence.

WFC3/ACS/UVIS 11360

Star Formation in Nearby Galaxies

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
integrated program on star formation in the nearby universe which will
fully exploit these new abilities. Our targets range from the
well-resolved R136 in 30 Dor 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 a (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 history of star
formation? (4) Is the stellar initial mass function universal or
determined by local conditions?

WFC3/IR 11108

Near Infrared Observations of a Sample of z~6.5-6.7 Galaxies

The majority of the most distant galaxies discovered to date have been
found by strong Lyman alpha emission at red optical wavelengths. An
accurate estimate of the star formation rates for these objects
requires a measurement of the line-free UV continuum, which must be
taken at infrared wavelengths. Here we propose to obtain imaging with
WFC3 in the F140W filter for a sample of 9 Lyman alpha galaxies with
redshifts z~6.5 up to z=6.740 from a complete, flux- limited widefield
narrowband and multi-color survey conducted on the 8-m Subaru
Telescope. This program will investigate galaxy morphologies and star
formation for a uniform sample of the highest redshift galaxies now
known.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark
current image scaled by desired exposure time. Therefore, dark current
images must be collected using all sample sequences that will be used
in science observations. These observations will be used to monitor
changes in the dark current of the WFC3-IR channel on a day-to-day
basis, and to build calibration dark current ramps for each of the
sample sequences to be used by GOs in Cycle 17. For each sample
sequence/array size combination, a median ramp will be created and
delivered to the calibration database system (CDBS).

WFC3/UV/ACS/WFC 11688

Exploring the Bottom End of the White Dwarf Cooling Sequence in the
Open Cluster NGC6819

The recent discovery by our group of an unexpectedly bright end of the
white-dwarf (WD) luminosity function (LF) of the metal-rich, old open
cluster NGC 6791 casts serious doubts on our understanding of the
physical process which rules the formation and the cooling of WDs. It
is clear at this point that the theory badly needs more observations.
Here we propose WFC3/UVIS and ACS/WFC HST observations reaching the
bottom end of the WD LF, for the first time in a solar-metallicity,
2.5-Gyr-old, populous open cluster: NGC 6819.

WFC3/UVIS 11657

The Population of Compact Planetary Nebulae in the Galactic Disk

We propose to secure narrow- and broad-band images of compact
planetary nebulae (PNe) in the Galactic Disk to study the missing link
of the early phases of post-AGB evolution. Ejected AGB envelopes
become PNe when the gas is ionized. PNe expand, and, when large
enough, can be studied in detail from the ground. In the interim, only
the HST capabilities can resolve their size, morphology, and central
stars. Our proposed observations will be the basis for a systematic
study of the onset of morphology. Dust properties of the proposed
targets will be available through approved Spitzer/IRS spectra, and so
will the abundances of the alpha- elements. We will be able thus to
explore the interconnection of morphology, dust grains, stellar
evolution, and populations. The target selection is suitable to
explore the nebular and stellar properties across the galactic disk,
and to set constraints on the galactic evolutionary models through the
analysis of metallicity and population gradients.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set
of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals throughout the
cycle to support subarray science observations. The internals from
this proposal, along with those from the anneal procedure (Proposal
11909), will be used to generate the necessary superbias and superdark
reference files for the calibration pipeline (CDBS).

WFC3/UVIS 11908

Cycle 17: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the
UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially found via an unexpected bowtie-shaped feature in flatfield
ratios, subsequent lab tests on similar e2v devices have since shown
that it is also present as simply an overall offset across the entire
CCD, i.e., a QE offset without any discernable pattern. These lab
tests have further revealed that overexposing the detector to count
levels several times full well fills the traps and effectively
neutralizes the bowtie. Each visit in this proposal acquires a set of
three 3x3 binned internal flatfields: the first unsaturated image will
be used to detect any bowtie, the second, highly exposed image will
neutralize the bowtie if it is present, and the final image will allow
for verification that the bowtie is gone.

WFC3/UVIS 11925

UVIS Detector Linearity

This proposal will measure the in-orbit linear response of the UVIS
detectors by sampling over the response curve through saturation. This
program uses exposures of a standard star field (NGC 1850) to measure
the absolute values, and exposures of a tungsten lamp to measure
positional variations in response, following a similar procedure as
the ground tests.

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 11 11
FGS REAcq 07 07
OBAD with Maneuver 07 07

SIGNIFICANT EVENTS: (None)