HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5094

PERIOD COVERED: 5am May 11 - 5am May 12, 2010 (DOY 131/09:00z-132/09:00z)

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               9                9      

FGS REAcq               8                8      

OBAD with Maneuver 7                7      

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.

STIS/CC 11654

UV Studies of a Core Collapse Supernova

Observations of the UV spectrum of core collapse SNe hold unique

information about nucleosynthesis, the mass loss history, shock physics

and dust formation in the explosion on massive stars. This proposal aims

at a detailed study of a bright core collapse SN, discovered by any of

the many ongoing surveys, either a Type IIP, IIn or Ibc supernova. We

will address the role of circumstellar interaction and mass loss through

CNO lines in the UV, the nature of dust formation from UV line profiles

and use the UV continuum as a diagnostic of non-thermal emission from

the shock. The overall goal of our team is to achieve a better

understanding of these objects by combining HST data with complementary

ground-based observations. We have used HST to obtain UV spectra from

the explosion to the nebular phase. Over the past decade, we have

conducted studies of nearby SNe with HST, and we have published an

extensive series of papers. When Nature provides a bright candidate, HST

should be ready to respond.

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CC 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 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF), and

calibrate the SBF distance method, in the F110W and F160W filters of the

Wide Field Camera 3 IR channel. Because of the very high throughput of

F110W and the good match of F160W to the standard H band, we anticipate

that both of these filters will be popular choices for galaxy

observations with WFC3/IR. The SBF signal is typically an order of

magnitude brighter in the near-IR than in the optical, and the

characteristics (sensitivity, FOV, cosmetics) of the WFC3/IR channel

will be enormously more efficient for SBF measurements than previously

available near-IR cameras. As a result, our proposed SBF calibration

will allow accurate distance derivation whenever an early-type or

bulge-dominated galaxy is observed out to a distance of 150 Mpc or more

(i.e., out to the Hubble flow) in the calibrated passbands. For

individual galaxy observations, an accurate distance is useful for

establishing absolute luminosities, black hole masses, linear sizes,

etc. Eventually, once a large number of galaxies have been observed

across the sky with WFC3/IR, this SBF calibration will enable accurate

mapping of the total mass density distribution in the local universe

using the data available in the HST archive. The proposed observations

will have additional important scientific value; in particular, we

highlight their usefulness for understanding the nature of multimodal

globular cluster color distributions in giant elliptical galaxies.

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/IR/S/C 12089

Persistence - Part 2

The IR detectors on WFC3, like other IR detectors, trap charge when

exposed to sources near or above the full well of the detector diodes.

This charge leaks out, producing detectable afterglow images for periods

which can last for several hours, depending on the amount of over

exposure. These visits, which consist of tungsten lamp exposures of

varying durations followed by darks, are intended to provide a better

calibration of persistence over the full area of the IR detector of

WFC3.

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 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 11697

Proper Motion Survey of Classical and SDSS Local Group Dwarf Galaxies

Using the superior resolution of HST, we propose to continue our proper

motion survey of Galactic dwarf galaxies. The target galaxies include

one classical dwarf, Leo II, and six that were recently identified in

the Sloan Digital Sky Survey data: Bootes I, Canes Venatici I, Canes

Venatici II, Coma Berenices, Leo IV, and Ursa Major II. We will observe

a total of 16 fields, each centered on a spectroscopically-confirmed

QSO. Using QSOs as standards of rest in measuring absolute proper

motions has proven to be the most accurate and most efficient method.

HST is our only option to quickly determine the space motions of the

SDSS dwarfs because suitable ground-based imaging is only a few years

old and such data need several decades to produce a proper motion. The

two most distant galaxies in our sample will require time baselines of

four years to achieve our goal of a 30-50 km/s uncertainty in the

tangential velocity; given this and the finite lifetime of HST, it is

imperative that first-epoch observations be taken in this cycle. The

SDSS dwarfs have dramatically lower surface brightnesses and

luminosities than the classical dwarfs. Proper motions are crucial for

determining orbits of the galaxies and knowing the orbits will allow us

to test theories for the formation and evolution of these galaxies and,

more generally, for the formation of the Local Group.

WFC3/UVIS 11730

Continued Proper Motions of the Magellanic Clouds: Orbits, Internal

Kinematics, and Distance

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in

the Magellanic Clouds centered on background quasars. We used these data

to determine the proper motions of the LMC and SMC to better than 5% and

15% respectively. The results had a number of unexpected implications

for the Milky Way-LMC-SMC system and received considerable attention in

the literature and in the press. The implied three-dimensional

velocities are larger than previously believed and close to the escape

velocity in a standard 10^12 solar mass Milky Way dark halo. Our orbit

calculations suggest the Clouds may not be bound to the Milky Way or may

just be on their first passage, both of which are unexpected in view of

traditional interpretations of the Magellanic Stream. Alternatively, the

Milky Way dark halo may be a factor two more massive than previously

believed, which would be surprising in view of other observational

constraints. Also, the relative velocity between the LMC and SMC was

larger than expected, leaving open the possibility that the Clouds may

not be bound to each other. To further verify and refine our results we

requested an additional epoch data in Cycle 16 which is being executed

with WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC

field shows that the field proper motion using all three epochs of data

is consistent within 1-sigma with the two- epoch data, thus verifying

that there are no major systematic effects in our previous measurements.

The random errors, however, are only smaller by a factor of 1.4 because

of the relatively large errors in the WFPC2 data. A prediction for a

fourth epoch with measurement errors similar to epochs 1 and 2 shows

that the uncertainties will improve by a factor of 3. This will allow us

to better address whether the Clouds are indeed bound to each other and

to the Milky Way. It will also allow us to constrain the internal

motions of various populations within the Clouds, and to determine a

distance to the LMC using rotational parallax. Continuation of this

highly successful program is therefore likely to provide important

additional insights. Execution in SNAPshot mode guarantees maximally

efficient use of HST resources.

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).