Daily 3921

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3921

PERIOD COVERED: UT August 10, 2005 (DOY 222)

OBSERVATIONS SCHEDULED

ACS/HRC 10377

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L-flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronagraphic
monitoring is required to assess the changing position of the spots.

ACS/HRC 10547

A SNAP Program to Obtain Complete Wavelength Coverage of Interstellar
Extinction

We propose a SNAP program to obtain ACS/HRC spectra in the near-UV
{PR200L} and near-IR {G800L} for a set of main sequence B stars with
available IUE UV spectrophotometry, optical photometry, and 2MASS IR
photometry. Together with these existing data, the new observations
will provide complete photometric and spectrophotometric coverage from
1150 to 11000 A and enable us to produce complete extinction curves
from the far-UV to the near-IR, with well- determined values of R{V}.
The proposed set of 50 program sight lines includes the full range of
interstellar extinction curve types and a wide range of color
excesses. The new data will allow us to examine variability in the
near-UV through near-IR spectral regions, including the UV-optical
"knee" and the "Very Broad Structure." We will examine the response of
these features to different interstellar environments and their
relationship to other curve features. These are largely unexplored
aspects of extinction curves which will provide additional constraints
on the properties of interstellar grains. The curves will be derived
using stellar atmosphere models to represent the intrinsic spectral
energy distributions of the program stars, eliminating the need to
observe unreddened "standard stars." This approach virtually
eliminates "mismatch error", allowing us to derive extinction curves
with much higher precision than previously possible. In addition, the
new spectra will provide higher S/N data for the peak of the 2175 A
bump than previously available.

ACS/HRC/WFC 10370

CCD Hot Pixel Annealing

Hot pixel annealing will continue to be performed once every 4 weeks.
The CCD TECs will be turned off and heaters will be activated to bring
the detector temperatures to about +20C. This state will be held for
approximately 12 hours, after which the heaters are turned off, the
TECs turned on, and the CCDs returned to normal operating condition.
To assess the effectiveness of the annealing, a bias and four dark
images will be taken before and after the annealing procedure for both
WFC and HRC. The HRC darks are taken in parallel with the WFC darks.
The charge transfer efficiency {CTE} of the ACS CCD detectors declines
as damage due to on-orbit radiation exposure accumulates. This
degradation has been closely monitored at regular intervals, because
it is likely to determine the useful lifetime of the CCDs. We will now
combine the annealling activity with the charge transfer efficiency
monitoring and also merge into the routine dark image collection. To
this end, the CTE monitoring exposures have been moved into this
proposal . All the data for this program is acquired using internal
targets {lamps} only, so all of the exposures should be taken during
Earth occultation time {but not during SAA passages}. 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. Extended Pixel Edge Response {EPER} and First Pixel
Response {FPR} data will be obtained over a range of signal levels for
both the Wide Field Channel {WFC}, and the High Resolution Channel
{HRC}.

ACS/SBC 10502

ACS Imaging of the Uranus Aurora and Hydrogen Corona

ACS SBC UV observations of Uranus are proposed with dual purposes that
can be achieved with a single set of observations. First, we propose
to observe the very unusual auroral of Uranus for the first time since
IUE and Voyager in the 1980's. The Uranus aurora are centered on the
magnetic poles, corresponding to the 60 deg. tilted magnetic moment,
closer to the equator than the rotational poles. The brighter auroral
emission appears around the weaker magnetic pole. The auroral
emissions are highly variable, as recorded with IUE, and the
rotational phase of Uranus is not known. The observations will
therefore cover the extent of a Uranus rotation {17.29 hours}, and
will be repeated one-half solar rotation later to allow for variations
in the solar wind at Uranus. The high sensitivity of the ACS SBC at
long wavelengths will increase the sensitivity to auroral H2
emissions, and observations in cycle 14 near solar minimum will limit
the sky background and reflected solar emissions from the Uranus disc.
Secondly, these images will measure the extended hydrogen corona of
Uranus, first seen by the Voyager 2 UVS. We propose to model the
distribution of the hydrogen corona to determine the source processes
in the Uranus upper atmosphere, by comparison with model runs from an
exospheric code.

ACS/WFC 10493

A Survey for Supernovae in Massive High-Redshift Clusters

We propose to measure, to an unprecedented 30% accuracy, the SN-Ia
rate in a sample of massive z=0.5-0.9 galaxy clusters. The SN-Ia rate
is a poorly known observable, especially at high z, and in cluster
environments. The SN rate and its redshift dependence can serve as
powerful discrimiminants for a number of key issues in astrophysics
and cosmology. Our observations will: 1. Put clear constraints on the
characteristic SN-Ia "delay time, " the typical time between the
formation of a stellar population and the explosion of some of its
members as SNe-Ia. Such constraints can exclude entire categories of
SN-Ia progenitor models, since different models predict different
delays. 2. Help resolve the question of the dominant source of the
high metallicity in the intracluster medium {ICM} - SNe-Ia, or
core-collapse SNe from an early stellar population with a top-heavy
IMF, perhaps those population III stars responsible for the early
re-ionization of the Universe. Since clusters are excellent
laboratories for studying enrichment {they generally have a simple
star-formation history, and matter cannot leave their deep
potentials}, the results will be relevant for understanding metal
enrichment in general, and the possible role of first generation stars
in early Universal enrichment. 3. Reveal, via nuclear variability, the
AGN fraction in clusters at this redshift, to be compared with the
field AGN fraction. This will be valuable input for understanding
black-hole demographics, AGN evolution, and ICM energetics. 4.
Potentially discover intergalactic cluster SNe, which can trace the
stripped stellar population at high z.

ACS/WFC 10587

Measuring the Mass Dependence of Early-Type Galaxy Structure

We propose two-color ACS-WFC Snapshot observations of a sample of 118
candidate early- type gravitational lens galaxies. Our lens-candidate
sample is selected to yield {in combination with earlier results} an
approximately uniform final distribution of 40 early-type strong
lenses across a wide range of masses, with velocity dispersions {a
dynamical proxy for mass} ranging from 125 to 300 km/s. The proposed
program will deliver the first significant sample of low-mass
gravitational lenses. All of our candidates have known lens and source
redshifts from Sloan Digital Sky Survey data, and all are bright
enough to permit detailed photometric and stellar- dynamical
observation. We will constrain the luminous and dark-matter mass
profiles of confirmed lenses using lensed-image geometry and
lens-galaxy structural/photometric measurements from HST imaging in
combination with dynamical measurements from spatially resolved
ground-based follow-up spectroscopy. Hence we will determine, in
unprecedented detail, the dependence of early-type galaxy mass
structure and mass-to-light ratio upon galaxy mass. These results will
allow us to directly test theoretical predictions for halo
concentration and star-formation efficiency as a function of mass and
for the existence of a cuspy inner dark- matter component, and will
illuminate the structural explanation behind the fundamental plane of
early-type galaxies. The lens-candidate selection and confirmation
strategy that we propose has been proven successful for high-mass
galaxies by our Cycle 13 Snapshot program {10174}. The program that we
propose here will produce a complementary and unprecedented lens
sample spanning a wide range of lens-galaxy masses.

NIC1/NIC2/NIC3 10380

Cycle 13 NICMOS dark current, shading profile, and read noise
monitoring program

The purpose of this proposal is to monitor the dark current, read
noise, and shading profile for all three NICMOS detectors throughout
the duration of Cycle 13. This proposal is an essentially unchanged
continuation of PID 9993 which cover the duration of Cycle 12.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration - CR Persistence Part 4

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 DARKSs. 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 10428

The colours of QSO host galaxies at z=2 and the evolution of their
stellar masses

We propose to use NICMOS imaging to measure the rest-frame optical/UV
colours of a complete sample of 10 QSO host galaxies at redshifts
between z=1.5 and z=2. From our cycle 11 HST observations {the GEMS
project} we know that QSO host galaxies at redshifts of z~1 show blue
colors despite having early-type morphologies. This is in excellent
agreement with recent SDSS results on low-z AGN hosts, suggesting that
QSO-type activity in galaxies correlates strongly with the presence of
a young stellar population. Our proposed NICMOS observations will
allow us to test the validity of this hypothesis out to z~2, by
relating the observed QSO host colours to those of normal galaxies at
similar redshifts taken from GOODS. We have already established within
GEMS that the QSO hosts in our sample possess substantial UV
luminosities, most likely originating from young stars. Knowing
rest-frame colors, we can estimate stellar ages and stellar masses.
For the first time will it be possible to determine the evolution of
stellar masses in QSO host galaxies from z=2, the epoch of maximum QSO
activity, to the present. Our results will shed light on the relation
between nuclear activity and the star formation history of galaxies,
and how these processes may jointly drive the cosmic evolution of QSOs
and galaxies.

NIC3 10406

NICMOS Imaging of Massive Galaxies at z ~ 2

We propose NICMOS F160W imaging of a sample of massive red galaxies
from the Gemini Deep Deep Survey. These galaxies dominate the stellar
mass density at 1.5 z 2 and are our best link to early galaxy
formation. The NICMOS images will be used in conjunction with our ACS
images and deep Gemini spectra to examine the formation and early
evolution of massive ellpitcal galaxy progenitors. We waive all
propretary rights to the data and wil make them available on our web
site as we have done with the Gemini Deep Deep Survey spectra,
catalogs and ACS images.

NIC3 9846

The Origins of Sub-stellar Masses: Searching for the End of the IMF

Is there a preferred scale that defines the end of the IMF? We propose
to test this hypothesis by conducting a deep spectroscopic survey of
extremely low mass objects in the embedded young cluster associated
with NGC1333. At a distance of only 300pc, this cluster is one of the
nearest examples of a dense young cluster. We will be able to obtain
R=200 spectra and photometry for 40-60 cluster members with masses
between 5-40 Jupiter masses at an age of 1 Myr observed through
A{v}10 mag. This will enable us to estimate temperatures and
luminosities for all sources detected in the survey. We will compare
their positions in an H-R diagram to PMS evolutionary tracks in order
to estimate their ages and masses. For a solar metallicity cloud at a
temperature of 10 K, the minimum mass for fragmentation is thought to
be 10 Jupiter masses. A statistically significant sample of objects
detected below this limit would challenge the role of hierarchical
fragmentation in limiting substellar masses. The proximity of this
cluster combined with the unique sensitivity, wavelength coverage, and
multi-object spectroscopic capability of NICMOS on HST make this
experiment possible.

WFPC2 10356

WFPC2 Cycle 13 Decontaminations and Associated Observations

This proposal is for the monthly WFPC2 decons. Also included are
instrument monitors tied to decons: photometric stability check, focus
monitor, pre- and post-decon internals {bias, intflats, kspots, &
darks}, UV throughput check, VISFLAT sweep, and internal UV flat
check. FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

9911 - GSacq(1,3,1) results in finelock (3,0,3), but Take Data Flag
was down due to Type T3 slew @ 222/1525z The GSacq(1,3,1) scheduled at
222/15:18:33 - 15:26:35 Z resulted in finelock backup (3,0,3) using
FGS-3, due to scan step limit exceeded on FGS-1, but the Take Data
Flag was down due to profile slew (T3) scheduled at 222/15:26:38
-15:34:52. Although the Vehicle Offset was successful, the (#44)
command, sequential updates were not executed. Subsequent REacq(1,3,1)
at 222/16:17:43 achived finelock backup (3,0,3). The Take Data Flag
was up.

COMPLETED OPS REQUEST:

Ops Request 17486-1 was executed successfully to offline the SA3, EPS Test 1,
rapid day-to-night transition.


COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS Gsacq 12 12
FGS Reacq 5 5
FHST Update 18 18
LOSS of LOCK

SIGNIFICANT EVENTS: (None)