Daily Report #4585

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** # 4585

PERIOD COVERED: UT April 08, 2008 (DOY 099)

OBSERVATIONS SCHEDULED

WFPC2 11024

WFPC2 CYCLE 15 INTERNAL MONITOR

This calibration proposal is the Cycle 15 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{both gain 7 and gain 15 -- to test stability of gains and bias
levels}, a test for quantum efficiency in the CCDs, and a monitor for
possible buildup of contaminants on the CCD windows. These also
provide raw data for generating annual super-bias reference files for
the calibration pipeline.

FGS 11295

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.

FGS 11298

Calibrating Cosmological Chronometers: White Dwarf Masses

We propose to use HST/FGS1R to determine White Dwarf {WD} masses. The
unmatched resolving power of HST/FGS1R will be utilized to follow up
four selected WD binary pairs. This high precision obtained with
HST/FGS1R simply cannot be equaled by any ground based technique. This
proposed effort complements that done by CoI Nelan in which a sample
of WDs is being observed with HST/FGS1R. This proposal will
dramatically increase the number of WDs for which dynamical mass
measurements are possible, enabling a better calibration of the WD
mass-radius relation, cooling curves, initial to final mass relations,
and ultimately giving important clues to the star formation history of
our Galaxy and the age of its disk as well as in other galaxies. {This
project is part of Subasavage's PhD thesis work at Georgia State
University.}

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be
non-standard reference files available to users with a USEAFTER
date/time mark. The keyword 'USEAFTER=date/time' will also be added to
the header of each POST-SAA DARK frame. The keyword must be populated
with the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

NIC2 11150

Beta Pic Polarimetry with NICMOS

Debris disk stars host transient dust grains that comprise a
collisional cascade with sizes ranging from planetesimals to the
sub-micron. In addition to the gravity of the host star and any
planets present, these grains are subject to size-dependent
non-gravitational forces, e.g., corpuscular drag and radiation
pressure. When a steep spectrum of grain sizes prevails, such as the
Dohnanyi distribution, scattered light images preferentially trace
grains with dimensionless size parameter of order unity. Thus images
in scattered starlight provide unique windows on the balance of forces
acting on grains at a specific size. Therefore, in an A star system
such as beta Pic, the near-IR is dominated by grains close to the blow
out size and therefore NICMOS traces dust on hyperbolic orbits.
Scattering is fundamentally polarization sensitive, and measurements
that record intensity literally see only half the picture. If linear
polarization is measured then the elements of the complex scattering
matrix can be reconstructed. These matrix elements provide fundamental
constraints on the size, composition and structure of the scatterers.
Notably, polarimetry can be used to break the degeneracy between
scattering asymmetry, g, and the radial dust gradient, which are
otherwise covariant in an edge-on disk. Thus, we can use polarimetry
to localize the parent bodies in the beta Pic disk.
In beta Pic, dust is thought to originate mainly from the sublimation
of cometary bodies near periastron. The irradiation of cometary
material leads to sublimation and photodissociation of ices forming
porous grains consisting of a matrix of refractory material. Such
grains have a characteristic scattering signature in polarized light
that can be distinguished from compact grains that arise from
collisional erosion of asteroidal material.

NIC3 11120

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic
Center

The Galactic center (GC) is a unique site for a detailed study of a
multitude of complex astrophysical phenomena, which may be common to
nuclear regions of many galaxies. Observable at resolutions
unapproachable in other galaxies, the GC provides an unparalleled
opportunity to improve our understanding of the interrelationships of
massive stars, young stellar clusters, warm and hot ionized gases,
molecular clouds, large scale magnetic fields, and black holes. We
propose the first large-scale hydrogen Paschen alpha line survey of
the GC using NICMOS on the Hubble Space Telescope. This survey will
lead to a high resolution and high sensitivity map of the Paschen
alpha line emission in addition to a map of foreground extinction,
made by comparing Paschen alpha to radio emission. This survey of the
inner 75 pc of the Galaxy will provide an unprecedented and complete
search for sites of massive star formation. In particular, we will be
able to (1) uncover the distribution of young massive stars in this
region, (2) locate the surfaces of adjacent molecular clouds, (3)
determine important physical parameters of the ionized gas, (4)
identify compact and ultra-compact HII regions throughout the GC. When
combined with existing Chandra and Spitzer surveys as well as a wealth
of other multi-wavelength observations, the results will allow us to
address such questions as where and how massive stars form, how
stellar clusters are disrupted, how massive stars shape and heat the
surrounding medium, and how various phases of this medium are
interspersed.

WFPC2 11017

Hubble Heritage Observations of SN1006

The Hubble Heritage team will obtain broadband images of SN1006 to
combine with the Halpha data obtained in proposal 10577 (PI: Raymond).
Three broadband filters will be used with two pointings of the WFPC2
to obtain star colors. A composite image of the Heritage stars along
with the Halpha filament will be created, resulting in a public
release image.

WFPC2 11040

Geometric Distortion / Astrometry Closeout

These observations will serve as a final characterization of the
geometric distortion and astrometric calibration. The Omega-Cen inner
calibration field is used. Filters F300W, F555W, and F814W are
observed at 5 roll angles spanning 180 degrees; F218W is observed at a
single roll angle.

WFPC2 11070

WFPC2 CYCLE 15 Standard Darks - part II

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 11113

Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution

The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising
and unexpected results. We have found a strong concentration of
binaries among low-inclination Classicals, a possible size cutoff to
binaries among the Centaurs, an apparent preference for nearly equal
mass binaries, and a strong increase in the number of binaries at
small separations. We propose to continue this successful program in
Cycle 16; we expect to discover at least 13 new binary systems,
targeted to subgroups where these discoveries can have the greatest
impact.

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************** 13****************** 13
FGS REacq************** 03****************** 03
OBAD with Maneuver **** 32****************** 31

SIGNIFICANT EVENTS: (None)