Notice: Due to the conversion of some ACS WFC or HRC observations into

WFPC2, or NICMOS observations after the loss of ACS CCD science

capability in January, there may be an occasional discrepancy between a

proposal's listed (and correct) instrument usage and the abstract that

follows it.

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       # 4484

PERIOD COVERED: UT November 06, 2007 (DOY 310)

OBSERVATIONS SCHEDULED

ACS/SBC 11215

New Sightlines for the Study of Intergalactic Helium: Dozens of

High-Confidence, UV- Bright Quasars from SDSS/GALEX

The reionization of IGM helium is thought to have occurred at redshifts

of z=3 to 4. Detailed study of HeII Lyman-alpha absorption toward a

handful of QSOs at 2.7<z<3.3 demonstrated the high potential of such IGM

probes, but the critically small sample size limits confidence in

cosmological inferences. The requisite unobscured sightlines to high-z

are extremely rare, but SDSS provides 5800, z>3.1 QSOs potentially

suitable for HeII studies. We've cross-correlated SDSS quasars with

GALEX UV sources to obtain dozens of new, high confidence, candidate

sightlines {z=3.1-4.9} potentially useful for detailed HeII studies with

HST. We propose brief, 2-orbit reconnaissance ACS SBC prism exposures

toward each of the best dozen new quasars, to definitively verify UV

flux down to HeII. Our combined SDSS/GALEX selection insures a high

confirmation rate, as the quasars are already known to be UV bright in

GALEX. Our program will provide a statistical sample of HeII sightlines

extending to high redshift, enabling future long exposure follow-up

spectra with the SBC prism, or superb quality COS or STIS spectra after

SM4. Stacks of our prism spectra will also directly yield ensemble

information. Ultimately, the new sightlines will enable confident

measures of the spectrum and evolution of the ionizing background, the

evolution of HeII opacity, the epoch of helium reionization, and the

density of IGM baryons.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

A new procedure proposed to alleviate the CR-persistence problem of

NICMOS. Dark frames will be obtained immediately upon exiting the SAA

contour 23, and every time a NICMOS exposure is scheduled within 50

minutes of coming out of the SAA. The darks will be obtained in parallel

in all three NICMOS Cameras. The POST-SAA darks will be non- standard

reference files available to users with a USEAFTER date/time mark. The

keyword 'USEAFTER=date/time' will also be added to the header of each

POST-SAA DARK frame. The keyword must be populated with the time, in

addition to the date, because HST crosses the SAA ~8 times per day so

each POST-SAA DARK will need to have the appropriate time specified, for

users to identify the ones they need. Both the raw and processed images

will be archived as POST-SAA DARKs. Generally we expect that all NICMOS

science/calibration observations started within 50 minutes of leaving an

SAA will need such maps to remove the CR persistence from the science

images. Each observation will need its own CRMAP, as different SAA

passages leave different imprints on the NICMOS detectors.

NIC2 11197

Sweeping Away the Dust: Reliable Dark Energy with an Infrared Hubble

Diagram

We propose building a high-z Hubble Diagram using type Ia supernovae

observed in the infrared rest-frame J-band. The infrared has a number of

exceptional properties. The effect of dust extinction is minimal,

reducing a major systematic that may be biasing dark energy

measurements. Also, recent work indicates that type Ia supernovae are

true standard candles in the infrared meaning that our Hubble diagram

will be resistant to possible evolution in the Phillip's relation over

cosmic time. High signal-to-noise measurements of 16 type Ia events at

z~0.4 will be compared with an independent optical Hubble diagram from

the ESSENCE project to test for a shift in the derived dark energy

equation of state due to a systematic bias. In Cycle 15 we obtained

NICMOS photometry of 8 ESSENCE supernovae and are awaiting template

observations to place them on the IR Hubble diagram. Here we request

another 8 supernovae be studied in the final season of the ESSENCE

search. Because of the bright sky background, H-band photometry of z~0.4

supernovae is not feasible from the ground. Only the superb image

quality and dark infrared sky seen by HST makes this test possible. This

experiment may also lead to a better, more reliable way of mapping the

expansion history of the universe with the Joint Dark Energy Mission.

NIC3 11334

NICMOS Cycle 16 Spectrophotometry

Observation of the three primary WD flux standards must be repeated to

refine the NICMOS absolute calibration and monitor for sensitivity

degradation. So far, NICMOS grism spectrophotometry is available for

only ~16 stars with good STIS spectra at shorter wavelengths. There are

more in the HST CALSPEC standard star data base with good STIS spectra

that would also become precise IR standards with NICMOS absolute SED

measurements. Monitoring the crucial three very red stars (M, L, T) for

variability and better S/N in the IR. Apparent variability was

discovered at shorter wavelengths during the ACS cross-calibration work

that revealed a ~2% discrepancy of the cool star fluxes with respect to

the hot primary WD standards. About a third of these stars are bright

enough to do in one orbit, the rest require 2 orbits.

WFPC2 11029

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly

Monitor

Intflat observations will be taken to provide a linearity check: the

linearity test consists of a series of intflats in F555W, in each gain

and each shutter. A combination of intflats, visflats, and earthflats

will be used to check the repeatability of filter wheel motions.

{Intflat sequences tied to decons, visits 1-18 in prop 10363, have been

moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note:

long-exposure WFPC2 intflats must be scheduled during ACS anneals to

prevent stray light from the WFPC2 lamps from contaminating long ACS

external exposures.

WFPC2 11038

Narrow Band and Ramp Filter Closeout

These observations are to improve calibration of narrow band and ramp

filters. We also test for changes in the filter properties during

WFPC2's 14 years on-board HST.

WFPC2 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

WFPC2 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!

WFPC2 11307

Completing the ACS Nearby Galaxy Survey with WFPC2

We are requesting 25 orbits of Director's Discretionary Time to complete

the primary science goals of our highly-ranked ACS Nearby Galaxy Survey

Treasury program {ANGST}. Our program lost ~2/3 of its orbits due to the

ACS failure. Roughly half of these were restored as a result of an

appeal to the Telescope Time Review Board which re-scoped the program.

The Board's response to our appeal was explicit in terms of which

targets were to be observed and how. We were directed to request

Director's discretionary time for the components of the appeal which

were not granted by the Review Board, but which were vital to the

success of the program. The observing strategy for ANGST is two-fold: to

obtain one deep field per galaxy which enables derivation of an accurate

ancient star formation history, and to obtain radial tilings sufficient

for recovering the full star formation history. The Review Board granted

WFPC2 observations for deep fields in 7 galaxies, but no time for radial

tilings. However, recovering the full star formation history of a galaxy

is not possible without additional radial coverage. We have searched the

archives for observations which may be used in place of the tilings

{conceding some of the Treasury goals, but providing significant

constraints on the full star formation history}, and have identified

suitable observations for all but two of the galaxies. Here we request

DD time for radial tilings for those last two galaxies.

WFPC2/ACS/HRC/WFPC 11020

Cycle 15 Focus Monitor

The focus of HST is measured primarily with ACS/HRC over full CVZ orbits

to obtain accurate mean focus values via a well sampled breathing curve.

Coma and astigmatism are also determined from the same data in order to

further understand orbital effects on image quality and optical

alignments. To monitor the stability of ACS to WFPC2 relative focii,

we've carried over from previous focus monitor programs parallel

observations taken with the two cameras at suitable orientations of

previously observed targets, and interspersed them with the HRC CVZ

visits.

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               06                  06                 

FGS REacq               06                  06               

OBAD with Maneuver 24                  24        

SIGNIFICANT EVENTS: (None)