HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science



DAILY REPORT #5149



PERIOD COVERED: 5am July 29 - 5am July 30, 2010 (DOY 210/09:00z-211/09:00z)



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 6 6

OBAD with Maneuver 6 6



SIGNIFICANT EVENTS: (None)





OBSERVATIONS SCHEDULED:



ACS/WFC3 11593



Dynamical Masses of the Coolest Brown Dwarfs



T dwarfs are excellent laboratories to study the evolution and the

atmospheric physics of both brown dwarfs and extrasolar planets. To

date, only a single T dwarf binary has a dynamical mass determination,

and more are sorely needed. The prospects of measuring more dynamical

masses over the next decade are limited to 6 known short-period T dwarf

binaries. We propose here to obtain Long-Term HST/ACS monitoring for the

3 of the 6 binaries which cannot be resolved with AO from the ground.

Upon completion, our program will substantially increase the number of T

dwarf dynamical mass measurements and thereby provide key benchmarks for

testing theoretical models of ultracool objects.



COS/NUV/FUV 12086



Generation of 1-D Fixed Pattern Templates



Tests have shown that application of a 1-D fixed pattern template to a

COS spectrum can reduce the fixed pattern noise in G130M or G160M

spectra to an equivalent S/N of about 30/1. For this to be occur, the

template must be derived from data for the same grating and nearly the

same central wavelength as the observation. This is because each grating

has a different cross dispersion profile, and different central

wavelengths fall at different cross dispersion detector locations. As a

result, spectra obtained at each grating and central wavelength setting

are derived from different regions of the detectors -- each with their

own, unique detector features and grid wire shadows.



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.



STS/MA/CC 12085



STIS/E230M Observations of HD6655 for Calibration of COS/G230L



This program observes HD 6655, a radial velocity target that is used for

calibrating COS/G230L. The objective of this program is to get STIS data

of this target, with the E230M grating, and then use this observations

to derive the offsets between the internal and external COS/G230L

wavelength scales.



WFC3/ACS/IR 11677



Is 47 Tuc Young? Measuring its White Dwarf Cooling Age and Completing a

Hubble Legacy



With this proposal we will firmly establish the age of 47 Tuc from its

cooling white dwarfs. 47 Tuc is the nearest and least reddened of the

metal-rich disk globular clusters. It is also the template used for

studying the giant branches of nearby resolved galaxies. In addition,

the age sensitive magnitude spread between the main sequence turnoff and

horizontal branch is identical for 47 Tuc, two bulge globular clusters

and the bulge field population. A precise relative age constraint for 47

Tuc, compared to the halo clusters M4 and NGC 6397, both of which we

recently dated via white dwarf cooling, would therefore constrain when

the bulge formed relative to the old halo globular clusters. Of

particular interest is that with the higher quality ACS data on NGC

6397, we are now capable with the technique of white dwarf cooling of

determining ages to an accuracy of +/-0.4 Gyrs at the 95% confidence

level. Ages derived from the cluster turnoff are not currently capable

of reaching this precision. The important role that 47 Tuc plays in

galaxy formation studies, and as the metal-rich template for the

globular clusters, makes the case for a white dwarf cooling age for this

metal-rich cluster compelling.



Several recent analyses have suggested that 47 Tuc is more than 2 Gyrs

younger than the Galactic halo. Others have suggested an age similar to

that of the most metal poor globular clusters. The current situation is

clearly uncertain and obviously a new approach to age dating this

important cluster is required.



With the observations of 47 Tuc, this project will complete a legacy for

HST. It will be the third globular cluster observed for white dwarf

cooling; the three covering almost the full metallicity range of the

cluster system. Unless JWST has its proposed bluer filters (700 and 900

nm) this science will not be possible perhaps for decades until a large

optical telescope is again in space. Ages for globular clusters from the

main sequence turnoff are less precise than those from white dwarf

cooling making the science with the current proposal truly urgent.



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 11554



Luminosity Profiles of Extremely Massive Clusters in NGC 7252



The galactic merger remnant NGC 7252 represents one of the most extreme

post-starburst environments in the local universe. During the disk-disk

merger (~400 Myr ago) this galaxy produced the largest young massive

star cluster population known, including two clusters above 10^7 Msun, a

factor of 100 more massive than typical globular clusters in the Milky

Way. We propose ACS-HRC observations of 3 fields in NGC 7252 in order to

explore the detailed properties, i.e. luminosity profiles, of these

massive star clusters. These observations will be able to test massive

cluster formation mechanisms (e.g. the cluster merger scenario) as well

as the possible tidal erosion and truncation of the outer regions of the

clusters by the galactic tidal field. These observations will compliment

our large on-going study using archival HST data, of star cluster

profiles outside the Local Group. The cluster population in NGC 7252

will extend our sample in cluster mass by an order of magnitude.



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.