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 are: (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)