HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3790
PERIOD COVERED: DOY 34
OBSERVATIONS SCHEDULED
ACS/WFC 10378
ACS Polarimetry Calibration
Observations are made of the Boomerang Nebula {highly polarized
reflection nebula} to calibrate the ACS polarizers.
ACS/WFC 10429
Streaming Towards Shapley: The Mass of the Richest Galaxy
Concentration in the Local Universe
The 600 km/s motion of the Local Group {LG} with respect to the cosmic
microwave background {CMB} is now known to high accuracy. However, its
precise origin remains poorly understood. The contribution to the
motion from the pull of the rich Shapley supercluster at z = 0.048 is
particularly controversial. This extreme mass concentration contains
more than 20 Abell clusters within 35 Mpc of its very rich central
cluster A3558, and is recognized as both the optically richest and the
most X-ray luminous structure in the local {z < 0.1} universe. Yet,
published values for the mass of Shapley continue to differ by an
order of magnitude, and recent estimates of its pull on the LG range
from negligible {20 km/s} to highly significant {300 km/s or more}.
Here we propose to resolve this key issue by using ACS to measure
high-precision surface brightness fluctuation {SBF} distances in order
to make a direct measurement of the infall towards Shapley. We will
target three Shapley foreground clusters where the infall is expected
to be high {possibly 1000 km/s or more}, as well as the Shapley core,
in order to test the assumption that it is at rest in the CMB. Prior
to ACS, the Shapley region was unreachable for SBF, but ACS doubles
the distance range of the SBF method with HST, enabling the distances
to be measured to the required accuracy. The proposed measurements
will place a firm limit on the largest mass fluctuation in the nearby
universe and finally determine its contribution to the observed CMB
dipole.
ACS/WFC/NIC3 10340
PANS
Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating universe, an extraordinary result that needs the most
rigorous test. The case for cosmic acceleration rests on the
observation that SNe Ia at z = 0.5 are about 0.25 mag fainter than
they would be in a universe without acceleration. A powerful and
straightforward way to assess the reliability of the SN Ia measurement
and the conceptual framework of its interpretation is to look for
cosmic deceleration at z > 1. This would be a clear signature of a
mixed dark-matter and dark-energy universe. Systematic errors in the
SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia
peak luminosity would not show this change of sign. We have obtained a
toehold on this putative ``epoch of deceleration'' with SN 1997ff at z
= 1.7, and 3 more at z > 1 from our Cycle 11 program, all found and
followed by HST. However, this is too important a test to rest on just
a few objects, anyone of which could be subject to a lensed
line-of-sight or misidentification. Here we propose to extend our
measurement with observations of twelve SNe Ia in the range 1.0 < z <
1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be
discovered as a byproduct from proposed Treasury and DD programs.
These objects will provide a much firmer foundation for a conclusion
that touches on important questions of fundamental physics.
NIC2 10176
Coronagraphic Survey for Giant Planets Around Nearby Young Stars
A systematic imaging search for extra-solar Jovian planets is now
possible thanks to recent progress in identifying "young stars near
Earth". For most of the proposed young {<~ 30 Myrs} and nearby {<~ 60
pc} targets, we can detect a few Jupiter-mass planets as close as a
few tens of AUs from the primary stars. This represents the first time
that potential analogs of our solar system - that is planetary systems
with giant planets having semi-major axes comparable to those of the
four giant planets of the Solar System - come within the grasp of
existing instrumentation. Our proposed targets have not been observed
for planets with the Hubble Space Telescope previously. Considering
the very successful earlier NICMOS observations of low mass brown
dwarfs and planetary disks among members of the TW Hydrae Association,
a fair fraction of our targets should also turn out to posses low mass
brown dwarfs, giant planets, or dusty planetary disks because our
targets are similar to {or even better than} the TW Hydrae stars in
terms of youth and proximity to Earth. Should HST time be awarded and
planetary mass candidates be found, proper motion follow-up of
candidate planets will be done with ground-based AOs.
NICMOS 8791
NICMOS Post-SAA calibration - CR Persistence Part 2
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.
WFPC2 10078
WFPC2 Cycle 12 Close-Out Photometric Cross-Calibration
This proposal is aimed at providing photometric zeropoint
cross-calibration between the commonly used WFPC2 photometric filter
sets and those that will be used for ACS and WFC3. The proposal
consists of observations of a set of standard stars, including the
SDSS primary standard BD+17D4708 {F5} and two red standard stars, VB8
{an M7- dwarf} and 2M0036+18 {L3.5 dwarf}. For the red stars, medium
and broad-band filters redward of F606W are calibrated, while for
BD+17D4708 an extensive set of 22 medium and broad-band filters is
used {from F185W to F1042M}. The intent is to observe these stars with
as many filters as possible, to eventually allow cross-calibration of
archival WFPC2 data with data from ACS, WFC3, SDSS and 2MASS.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None
COMPLETED OPS REQs: None
OPS NOTES EXECUTED: None
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 09 09
FGS Reacq 06 06
FHST Update 14 14
LOSS of LOCK
SIGNIFICANT EVENTS: None
