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HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5191

PERIOD COVERED: 8:00pm September 27 - 7:59pm September 28, 2010 (DOY 271/00:00z-271/23:59z)

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               8              8

FGS REAcq               8              8  

OBAD with Maneuver 6              6

SIGNIFICANT EVENTS: (None)

OBSERVATIONS SCHEDULED:

ACS/WFC3 11882

CCD Hot Pixel Annealing

This program continues the monthly anneal that has taken place every

four weeks for the last three cycles. We now obtain WFC biases and darks

before and after the anneal in the same sequence as is done for the ACS

daily monitor (now done 4 times per week). So the anneal observation

supplements the monitor observation sets during the appropriate week.

Extended Pixel Edge Response (EPER) and First Pixel Response (FPR) data

will be obtained over a range of signal levels for the Wide Field

Channel (WFC). This program emulates the ACS pre-flight ground

calibration and post-launch SMOV testing (program 8948), so that results

from each epoch can be directly compared. The High Resolution Channel

(HRC) visits have been removed since it could not be repaired during

SM4.

This program also assesses the read noise, bias structure, and amplifier

cross-talk of ACS/WFC using the GAIN=1.4 A/D conversion setting. This

investigation serves as a precursor to a more comprehensive study of WFC

performance using GAIN=1.4.

COS/NUV/FUV 11535

COS-GTO: Deep Search for an Oxygen Atmosphere on Callisto

We plan a deep search for 1304? and 1356? O emission from Callisto, to

detect or place strong limits on the presence of a hypothesized O2

atmosphere on this moon (Liang et al. 2005). Tenuous oxygen atmospheres

on Europa and Ganymede have been detected by HST using these emission

lines, but searches for O emission from Callisto have not been

successful (Strobel et al. 2002). The Liang et al. models predict O

emission at levels comparable to the Strobel et al. upper limit, so the

improved sensitivity of COS may be able to detect the emission, and thus

Callisto's O2 atmosphere, for the first time.

S/C 12046

COS FUV DCE Memory Dump

Whenever the FUV detector high voltage is on, count rate and current

draw information is collected, monitored, and saved to DCE memory. Every

10 msec the detector samples the currents from the HV power supplies

(HVIA, HVIB) and the AUX power supply (AUXI). The last 1000 samples are

saved in memory, along with a histogram of the number of occurrences of

each current value.

In the case of a HV transient (known as a "crackle" on FUSE), where one

of these currents exceeds a preset threshold for a persistence time, the

HV will shut down, and the DCE memory will be dumped and examined as

part of the recovery procedure. However, if the current exceeds the

threshold for less than the persistence time (a "mini-crackle" in FUSE

parlance), there is no way to know without dumping DCE memory. By

dumping and examining the histograms regularly, we will be able to

monitor any changes in the rate of "mini-crackles" and thus learn

something about the state of the detector.

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 11847

CCD Bias Monitor-Part 2

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.

WFC3/IR 12307

A public SNAPSHOT Survey of Gamma-ray Burst Host Galaxies

We propose to conduct a public infrared survey of the host galaxies of

Swift selected gamma-ray bursts (GRBs) at z<3. By obtaining deep,

diffraction limited imaging in the IR we will complete detections for

the host galaxies, and in concert with our extensive ground based

afterglow and host programmes will compile a detailed catalog of the

properties of high-z galaxies selected by GRBs. In particular these

observations will enable us to study the colours, luminosities and

morphologies of the galaxies. This in turn informs studies of the nature

of the progenitors and the role of GRBs as probes of star formation

across cosmic history. Ultimately it provides a product of legacy value

which will greatly complement further studies with next generation

facilities such as ALMA and JWST.

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 11635

In Search of SNIb/Ic Wolf-Rayet Progenitors and Comparison with Red

Supergiants (SNII Progenitors) in the Giant ScI Spiral M101

We propose to test two of the clearest predictions of the theory of

evolution of massive-star evolution: 1) The formation of Wolf-Rayet

stars depends strongly on these stars' metallicity (Z), with relatively

fewer WR stars forming at lower Z, and 2) Wolf-Rayet stars die as Type

Ib or Ic supernovae. To carry out these tests we propose a deep,

narrowband imaging survey of the massive star populations in the ScI

spiral galaxy M101. Just as important, we will test the hypothesis that

Superclusters like 30 Doradus are always richly populated with WR stars,

and by implication that these complexes are responsible for the spectral

signatures of starburst galaxies.

Our previous HST survey of the HII regions in the ScIII galaxy NGC 2403

suggested that the distribution of WR stars and RSG is a sensitive

diagnostic of the recent star-forming history of these large complexes:

young cores of O and WR stars are surrounded by older halos containing

RSG. Theory predicts that this must change with metallicity; relatively

fewer WR stars form at lower Z. A key goal of our proposal is to

directly test this paradigm in a single galaxy, M101 being the ideal

target. The abundance gradient across M101 (a factor of 20) suggests

that relatively many more WR will be found in the inner parts of this

galaxy than in the outer "suburbs". Second, we note that WR stars are

predicted to end their lives as core-collapse or pair-instability

supernovae. The WR population in M101 may be abundant enough for one to

erupt as a Type Ib or Ic supernova within a generation. The clear a

priori identification of a WR progenitor would be a major legacy of HST.

Third, we will also determine if "superclusters", heavily populated by

WR stars, are common in M101. It is widely claimed that such

Superclusters produce the integrated spectral signatures of Starburst

galaxies. We will be able to directly measure the numbers and

emission-line luminosities of thousands of Wolf Rayet stars located in

hundreds of M101 Superclusters, and correlate those numbers against the

Supercluster sizes and luminosities. It is likely (but far from certain)

that Supercluster sizes and emission-line luminosities are driven by

their Wolf-Rayet star content. Our sample will be the largest and

best-ever Supercluster/Wolf Rayet sample, an excellent local proxy for

characterizing starburst galaxies' Superclusters.

WFC3/UV 12348

WFC3/UVIS Charge Injection Test

In preparation for making charge injection (CI) available to observers,

this proposal will 1) confirm that the CI performs on-orbit as it did on

the ground, 2) provide an initial assessment of which CI mode is most

effective (10, 17, 25 line or continuous), and 3) obtain a baseline

calibration for each mode.

WFC3/UV/IR 11664

The WFC3 Galactic Bulge Treasury Program: Populations, Formation

History, and Planets

Exploiting the full power of the Wide Field Camera 3 (WFC3), we propose

deep panchromatic imaging of four fields in the Galactic bulge. These

data will enable a sensitive dissection of its stellar populations,

using a new set of reddening-free photometric indices we have

constructed from broad-band filters across UV, optical, and near-IR

wavelengths. These indices will provide accurate temperatures and

metallicities for hundreds of thousands of individual bulge stars.

Proper motions of these stars derived from multi-epoch observations will

allow separation of pure bulge samples from foreground disk

contamination. Our catalogs of proper motions and panchromatic

photometry will support a wide range of bulge studies.

Using these photometric and astrometric tools, we will reconstruct the

detailed star-formation history as a function of position within the

bulge, and thus differentiate between rapid- and extended-formation

scenarios. We will also measure the dependence of the stellar mass

function on metallicity, revealing how the characteristic mass of star

formation varies with chemistry. Our sample of bulge stars with accurate

metallicities will include 12 candidate hosts of extrasolar planets.

Planet frequency is correlated with metallicity in the solar

neighborhood; our measurements will extend this knowledge to a remote

environment with a very distinct chemistry.

Our proposal also includes observations of six well-studied globular and

open star clusters; these observations will serve to calibrate our

photometric indices, provide empirical population templates, and

transform the theoretical isochrone libraries into the WFC3 filter

system. Besides enabling our own program, these products will provide

powerful new tools for a host of other stellar-population investigations

with HST/WFC3. We will deliver all of the products from this Treasury

Program to the community in a timely fashion.

WFC3/UVIS 11729

Photometric Metallicity Calibration with WFC3 Specialty Filters

The community has chosen to include several filters in the WFC3 filter

complement that have been designed to allow fairly precise estimates of

stellar metallicities, and many science programs are enabled by this

capability. Since these filters do not exactly match those used for this

purpose on the ground, however, the mapping of stellar colors to stellar

metallicities needs to be calibrated. We propose to achieve this

calibration through observations of five stellar clusters with well

known metallicities. We will calibrate several different filter

calibrations which will allow future users to determine what filter

combination best meets their science needs.

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/IR 11644

A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into

the Formation of the Outer Solar System

The eight planets overwhelmingly dominate the solar system by mass, but

their small numbers, coupled with their stochastic pasts, make it

impossible to construct a unique formation history from the dynamical or

compositional characteristics of them alone. In contrast, the huge

numbers of small bodies scattered throughout and even beyond the

planets, while insignificant by mass, provide an almost unlimited number

of probes of the statistical conditions, history, and interactions in

the solar system. To date, attempts to understand the formation and

evolution of the Kuiper Belt have largely been dynamical simulations

where a hypothesized starting condition is evolved under the

gravitational influence of the early giant planets and an attempt is

made to reproduce the current observed populations. With little

compositional information known for the real Kuiper Belt, the test

particles in the simulation are free to have any formation location and

history as long as they end at the correct point. Allowing compositional

information to guide and constrain the formation, thermal, and

collisional histories of these objects would add an entire new dimension

to our understanding of the evolution of the outer solar system. While

ground based compositional studies have hit their flux limits already

with only a few objects sampled, we propose to exploit the new

capabilities of WFC3 to perform the first ever large-scale

dynamical-compositional study of Kuiper Belt Objects (KBOs) and their

progeny to study the chemical, dynamical, and collisional history of the

region of the giant planets. The sensitivity of the WFC3 observations

will allow us to go up to two magnitudes deeper than our ground based

studies, allowing us the capability of optimally selecting a target list

for a large survey rather than simply taking the few objects that can be

measured, as we have had to do to date. We have carefully constructed a

sample of 120 objects which provides both overall breadth, for a general

understanding of these objects, plus a large enough number of objects in

the individual dynamical subclass to allow detailed comparison between

and within these groups. These objects will likely define the core

Kuiper Belt compositional sample for years to come. While we have many

specific results anticipated to come from this survey, as with any

project where the field is rich, our current knowledge level is low, and

a new instrument suddenly appears which can exploit vastly larger

segments of the population, the potential for discovery -- both

anticipated and not -- is extraordinary.

-Lynn                                                  

Lynn F. Bassford               office#: 301-286-2876 
Hubble Space Telescope
CHAMP Mission Operations Manager
CHAMP Flight Operations Team Manager
Lockheed Martin Mission Services (LMMS)

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