Daily Report #4929

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #4929

PERIOD COVERED: 5am September 11 - 5am September 14, 2009 (DOY 254/09:00z-257/09:00z)

OBSERVATIONS SCHEDULED

WFC3/UVIS 11998

Determining the Rotational Phase of Comet 9P/Tempel 1 in Support of
the StardustNExT Mission

A primary objective of the StardustNExT mission is to image the crater
created by NASA's Deep Impact (DI) mission. The 12-year ground- and
space-based DI observing campaign provided an exceptional data set for
investigating the rotation of comet 9P/Tempel 1. The just-completed
analysis shows that the spin period increased in a stepwise manner
through the perihelia in 2000 and 2005, due to an outgassing of water
from a southern jet. Our water-sublimation jet torque model has been
moderately successful in predicting the integrated change in the
nucleus longitude at the 2005 perihelion and beyond, and has been used
to predict the rotation state at the planned Stardust-NExT encounter
just after perihelion on 02/14/2011. We propose a 19-orbit Hubble
program to perform light curve observations of 9P/Tempel 1 that will
allow us to determine the time-of-arrival adjustment of the
Stardust-NExT spacecraft trajectory that is needed to ensure that the
spacecraft arrives at encounter with the (as yet unseen) artificial DI
crater at the sub-spacecraft point and fully illuminated by the sun.
The trajectory correction maneuver is in Feb 2010, and we need to know
the nucleus rotation phase to a precision of 1% and the period to 10
sec by Jan 2010. HST is the only facility capable of obtaining the
high-quality data necessary to determine the shape and phase of the
rotational light curve. When combined with ground-based data 2-3
months later, we will achieve the required precision.

FGS 11942

Increasing the Accuracy of HST Astrometry with FGS1R

We propose to observe six exoplanetary system host stars and two
planetary nebulae central stars with FGS1R. All objects have been
previously observed under proposals GO-09233, -09969, -10989, and
-11210. These observations will significantly extend the time
baseline, permitting improvements in the determination of proper
motion. This systematic motion must be removed to get at the
perturbation of interest, either due to exoplanetary companions or the
orbital motion of the Earth (parallax). In most cases the perturbation
orbits will also improve. We improve either companion mass or PN
parallax. For one target, GJ 876, theoretical dynamical modelers have
proposed an inclination closer to 50 degrees, while FGS3 measurements
indicated an inclination closer to 84 degrees. These new data, once
combined with our older FGS3 data, will permit an independent
remeasurement of the inclination of the outermost companion, and a re-
evaluation of widely used dynamical algorithms.

WFC3/UVIS 11935

UVIS G280 Wavelength Calibration

Wavelength calibration of the UVIS G280 grism will be established
using observations of the Wolf Rayet star WR14. Accompanying direct
exposures will provide wavelength zeropoints for dispersed exposures.
The calibrations will be obtained at the central position of each CCD
chip and at the center of the UVIS field. No additional field-
dependent variations will be obtained.

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/UVIS 11924

WFC3/UVIS External and Internal CTE Monitor

CCD detector Charge Transfer Inefficiency (CTI)-induced losses in
photometry and astrometry will be measured using observations of the
rich open cluster NGC6791 and with the EPER (Extended Pixel Edge
Response) method using tungsten lamp flat field exposures. Although we
do not expect to see CTE effects at the outset of Cycle 17, this CTE
monitoring program is the first of a multi-cycle program to monitor
and establish CTE-induced losses with time. We expect to measure CTE
effects with a precision comparable to the ACS measurements.

WFC3/UVIS 11912

UVIS Internal Flats

This proposal will be used to assess the stability of the flat field
structure for the UVIS detector throughout the 15 months of Cycle 17.
The data will be used to generate on- orbit updates for the delta-flat
field reference files used in the WFC3 calibration pipeline, if
significant changes in the flat structure are seen.

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 11907

UVIS Cycle 17 Contamination Monitor

The UV throughput of WFC3 during Cycle 17 is monitored via weekly
standard star observations in a subset of key filters covering
200-600nm and F606W, F814W as controls on the red end. The data will
provide a measure of throughput levels as a function of time and
wavelength, allowing for detection of the presence of possible
contaminants.

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).

ACS/WFC3 11879

CCD Daily Monitor (Part 1)

This program comprises basic tests for measuring the read noise and
dark current of the ACS WFC and for tracking the growth of hot pixels.
The recorded frames are used to create bias and dark reference images
for science data reduction and calibration. This program will be
executed four days per week (Mon, Wed, Fri, Sun) for the duration of
Cycle 17. To facilitate scheduling, this program is split into three
proposals. This proposal covers 352 orbits (22 weeks) from 31 August
2009 to 31 January 2010.

STIS/CCD/MA1/MA2 11860

MAMA Spectroscopic Sensitivity and Focus Monitor

the purpose of this proposal is to monitor the sensitivity of each
MAMA grating mode to detect any change due to contamination or other
causes, and to also monitor the STIS focus in a spectroscopic and an
imaging mode.

STIS/CCD 11852

STIS CCD Spectroscopic Flats C17

The purpose of this proposal is to obtain pixel-to-pixel lamp flat
fields for the STIS CCD in spectroscopic mode.

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/CCD 11844

CCD Dark Monitor Part 1

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

FGS 11790

HST/FGS Astrometric Search for Young Planets Around Beta Pic and AU
Mic

AU Mic is a nearby Vega-type debris disk star. Its disk system has
been spatially resolved in exquisite detail, predominantly via the ACS
coronagraph and WFPC2 cameras onboard HST. These images exhibit a
wealth of morphological features which provide compelling indirect
evidence that AU Mic likely harbors short-period planetary
body/bodies. We propose to use the superlative astrometric
capabilities of HST/FGS to directly detect these planets, hence
provide the first direct planet detection in a Vega- type system whose
disk has been imaged at high spatial resolution.

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 W Vir
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.

FGS 11704

The Ages of Globular Clusters and the Population II Distance Scale

Globular clusters are the oldest objects in the universe whose age can
be accurately determined. The dominant error in globular cluster age
determinations is the uncertain Population II distance scale. We
propose to use FGS 1R to obtain parallaxes with an accuracy of 0.2
milliarcsecond for 9 main sequence stars with [Fe/H] -1.5. This will
determine the absolute magnitude of these stars with accuracies of
0.04 to 0.06mag. This data will be used to determine the distance to
24 metal-poor globular clusters using main sequence fitting. These
distances (with errors of 0.05 mag) will be used to determine the ages
of globular clusters using the luminosity of the subgiant branch as an
age indicator. This will yield absolute ages with an accuracy of 5%,
about a factor of two improvement over current estimates. Coupled with
existing parallaxes for more metal-rich stars, we will be able to
accurately determine the age for globular clusters over a wide range
of metallicities in order to study the early formation history of the
Milky Way and provide an independent estimate of the age of the
universe.

The Hipparcos database contains only 1 star with [Fe/H] -1.4 and an
absolute magnitude error less than 0.18 mag which is suitable for use
in main sequence fitting. Previous attempts at main sequence fitting
to metal-poor globular clusters have had to rely on theoretical
calibrations of the color of the main sequence. Our HST parallax
program will remove this source of possible systematic error and yield
distances to metal- poor globular clusters which are significantly
more accurate than possible with the current parallax data. The HST
parallax data will have errors which are 10 times smaller than the
current parallax data. Using the HST parallaxes, we will obtain main
sequence fitting distances to 11 globular clusters which contain over
500 RR Lyrae stars. This will allow us to calibrate the absolute
magnitude of RR Lyrae stars, a commonly used Population II distance
indicator.

ACS/WFC3 11670

The Host Environments of Type Ia Supernovae in the SDSS Survey

The Sloan Digital Sky Survey Supernova Survey has discovered nearly
500 type Ia supernovae and created a large, unique, and uniform sample
of these cosmological tools. As part of a comprehensive study of the
supernova hosts, we propose to obtain Hubble ACS images of a large
fraction of these galaxies. Integrated colors and spectra will be
measured from the ground, but we require high-resolution HST imaging
to provide accurate morphologies and color information at the site of
the explosion. This information is essential in determining the
systematic effects of population age on type Ia supernova luminosities
and improving their reliability in measuring dark energy. Recent
studies suggest two populations of type Ia supernovae: a class that
explodes promptly after star-formation and one that is delayed by
billions of years. Measuring the star-formation rate at the site of
the supernova from colors in the HST images may be the best way to
differentiate between these classes.

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.

STIS/MA1 11649

Elucidating the Mystery of the Io Footprint Time Variations

The Io UV footprint (IFP) is an auroral emission on Jupiter consisting
of one or more spots resulting from the electromagnetic interaction
between Io and the Jovian magnetosphere. Recent UV HST observations of
the Jovian aurora raised new issues and put previous interpretations
under question. Dedicated STIS Time-Tag observations based on only 3
HST orbits will help us to directly answer the following questions and
test new hypothesis on the physics driving their associated
phenomenon.

The proposed observations will determine whether the previously
observed short timescale (~2 min) variations of the IFP are periodic
or burst events. If the (quasi-) periodicity is established, these
constraints will help us to understand the origin of these variations.
These observations will also clarify the conditions of occurrence of
the unexpected quasi-simultaneous variations of the southern multiple
spots of the IFP. Moreover, we propose to observe the emergence of the
southern leading (or precursor) spot and the possible evolution of its
brightness. These two elements might validate or exclude the recently
proposed idea that cross-hemisphere electron beams or strong non-
linearities of the electromagnetic interaction explain the presence of
the leading and secondary spots.

ACS/WFC3 11599

Distances of Planetary Nebulae from SNAPshots of Resolved Companions

REliable distances to individual planetary nebulae (PNe) in the Milky
Way are needed to advance our understanding of their spatial
distribution, birthrates, influence on galactic chemistry, and the
luminosities and evolutionary states of their central stars (CSPN).
Few PNe have good distances, however. One of the best ways to remedy
this problem is to find resolved physical companions to the CSPN and
measure their distances by photometric main-sequence fitting. We have
previously used HST to identify and measure probable companions to 10
CSPN, based on angular separations and statistical arguments only. We
now propose to use HST to re-observe 48 PNe from that program for
which additional companions are possibly present. We then can use the
added criterion of common proper motion to confirm our original
candidate companions and identify new ones in cases that could not
confidently be studied before. We will image the region around each
CSPN in the V and I bands, and in some cases in the B band. Field
stars that appear close to the CSPN by chance will be revealed by
their relative proper motion during the 13+ years since our original
survey, leaving only genuine physical companions in our improved and
enlarged sample. This study will increase the number of Galactic PNe
with reliable distances by 50 percent and improve the distances to PNe
with previously known companions.

WFC3/UVIS 11588

Galaxy-Scale Strong Lenses from the CFHTLS Survey

We aim to investigate the origin and evolution of early-type galaxies
using gravitational lensing, modeling the mass profiles of objects
over a wide range of redshifts. The low redshift (z = 0.2) sample is
already in place following the successful HST SLACS survey; we now
propose to build up and analyze a sample of comparable size (~50
systems) at high redshift (0.4 z 0.9) using HST WFC3 Snapshot
observations of lens systems identified by the SL2S collaboration in
the CFHT legacy survey.

WFC3/UVIS 11565

A Search for Astrometric Companions to Very Low-Mass, Population II
Stars

We propose to carry out a Snapshot search for astrometric companions
in a subsample of very low-mass, halo subdwarfs identified within 120
parsecs of the Sun. These ultra-cool M subdwarfs are local
representatives of the lowest-mass H burning objects from the Galactic
Population II. The expected 3-4 astrometric doubles that will be
discovered will be invaluable in that they will be the first systems
from which gravitational masses of metal-poor stars at the bottom of
the main sequence can be directly measured.

COS/FUV 11482

FUV Detector Dark

Measure the FUV detector dark rate by taking long science exposures
with no light on the detector. The detector dark rate and spatial
distribution of counts will be compared to pre-launch data in order to
verify the nominal operation of the detector, and for use in the
CalCOS calibration pipeline. Variations of count rate as a function of
orbital position will be analyzed to find dependence of dark rate on
proximity to the SAA.

This is SMOV Activity COS-24.

COS/NUV 11473

COS NUV Imaging Performance Verification

This activity is designed to verify the performance of the COS/NUV
imaging mode. In particular, the PSF quality will be assessed and the
plate scale will be measured. The throughput of the Mirror A with both
the PSA and BOA will be fully calibrated by observing an appropriate
HST flux standard star, and will be characterized as a function of
location within the aperture by moving the star from the center to
various positions with a grid pattern. The relative throughput of
Mirror A vs. Mirror B will also be evaluated in the center of both the
PSA and BOA. This activity will be structured in a way that will also
allow for testing of the drift following the OSM motion in imaging
mode and for testing of the image stability within an orbit and over
several orbits.

WFC3/UVIS 11432

UVIS Internal Flats

This proposal will be used to assess the stability of the flat field
structure for the UVIS detector. Flat fields will be obtained for all
filters using the internal D2 and tungsten lamps.

This proposal corresponds to Activity Description ID WF19. It should
execute only after the following proposals have executed:
WF08 - Proposal 11421
WF09 - Proposal 11422
WF11 - Proposal 11424
WF15 - Proposal 11428

WFC3/IR 11208

The Co-Evolution of Spheroids and Black Holes in the Last Six Billion
Years

The masses of giant black holes are correlated with the luminosities,
masses, and velocity dispersions of the bulges of their host galaxies.
This empirical correlation of phenomena on widely different scales
(from pcs to kpcs) suggests that the formation and evolution of
galaxies and central black holes are closely linked. In Cycle 13, we
have started a campaign to map directly the co-evolution of spheroids
and black-holes by measuring in observationally favorable redshift
windows the empirical correlations connecting their properties. By
focusing on Seyfert 1s, where the nucleus and the stars contribute
comparable fractions of total light, black hole mass and bulge
dispersion are obtained from Keck spectroscopy. HST is required for
accurate measurement of the non- stellar AGN continuum, the morphology
of the galaxy, and the structural parameters of the bulge. The results
at z=0.36 indicate a surprisingly fast evolution of bulges in the past
4 Gyrs (significant at the 95%CL), in the sense that bulges were
significantly smaller for a given black hole mass. Also, the large
fraction of mergers and disturbed galaxies (4+2 out of 20) identifies
gas-rich mergers as the mechanisms responsible for bulge- growth.
Going to higher redshift - where evolutionary trends should be
stronger - is needed to confirm these tantalizing results. We propose
therefore to push our investigation to the next suitable redshift
window z=0.57 (lookback-time 6 Gyrs). Fifteen objects are the minimum
number required to map the evolution of the empirical correlations
between bulge properties and black-hole mass, and to achieve a
conclusive detection of evolution (99%CL).

WFC3/IR 11202

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

The structure, formation and evolution of early-type galaxies is still
largely an open problem in cosmology: how does the Universe evolve
from large linear scales dominated by dark matter to the highly
non-linear scales of galaxies, where baryons and dark matter both play
important, interacting, roles? To understand the complex physical
processes involved in their formation scenario, and why they have the
tight scaling relations that we observe today (e.g. the Fundamental
Plane), it is critically important not only to understand their
stellar structure, but also their dark-matter distribution from the
smallest to the largest scales. Over the last three years the SLACS
collaboration has developed a toolbox to tackle these issues in a
unique and encompassing way by combining new non-parametric strong
lensing techniques, stellar dynamics, and most recently weak
gravitational lensing, with high-quality Hubble Space Telescope
imaging and VLT/Keck spectroscopic data of early-type lens systems.
This allows us to break degeneracies that are inherent to each of
these techniques separately and probe the mass structure of early-type
galaxies from 0.1 to 100 effective radii. The large dynamic range to
which lensing is sensitive allows us both to probe the clumpy
substructure of these galaxies, as well as their low-density outer
haloes. These methods have convincingly been demonstrated, by our
team, using smaller pilot-samples of SLACS lens systems with HST data.
In this proposal, we request observing time with WFC3 and NICMOS to
observe 53 strong lens systems from SLACS, to obtain complete
multi-color imaging for each system. This would bring the total number
of SLACS lens systems to 87 with completed HST imaging and effectively
doubles the known number of galaxy- scale strong lenses. The deep HST
images enable us to fully exploit our new techniques, beat down
low-number statistics, and probe the structure and evolution of
early-type galaxies, not only with a uniform data-set an order of
magnitude larger than what is available now, but also with a
fully-coherent and self-consistent methodological approach!

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

12013 - REAcq(2,3,3) scheduled at 255/06:42:04z - 06:46:30z was
observed to have failed to RGA Hold (gyro control) due to search
radius limit exceeded on FGS-2.

Observations affected: STIS 74 - 76, Proposal ID# 11860

COMPLETED OPS REQUEST:

18700-0 - Null genslew for proposal 11492 - slot 1 @ 254/19:30z

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 37 37
FGS REAcq 11 10
OBAD with Maneuver 24 24

SIGNIFICANT EVENTS: (None)