Daily # 4221

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4221

PERIOD COVERED: UT October 17, 2006 (DOY 290)

OBSERVATIONS SCHEDULED

ACS/WFC 10595

A Reference Database for Accurate Ages and Metallicities of Globular
Clusters in the Magellanic Clouds

We propose to finalize the compilation of a comprehensive database of
high-quality ages and metallicities of Simple Stellar Populations
{SSPs} in the Milky Way and the Magellanic Clouds. We will acquire new
ACS imagery for 8 young and intermediate-age globular clusters in the
Magellanic Clouds to create high-quality color-magnitude diagrams
{CMDs} to enable accurate measurements of their ages and
metallicities. In concert with a similar analysis of CMD data already
available in the HST archive for 8 more such GCs, the resulting
database will provide a well-sampled coverage of the full range of
ages and metallicities known among globular clusters {0.5 = Age {Gyr}
= 13.5 and -2.3 = [Fe/H] = +0.1, respectively}. This database will
form the crucial basis for our ongoing, comprehensive multi-wavelength
program to: {1} establish empirical relations among SSP colors {from
the UV [GALEX] through the mid-IR [Spitzer]}, line strengths, ages and
metallicities, and {2} provide a stringent test of the systemic
accuracy of age and metallicity determinations using state-of-the-art
population synthesis models.

ACS/WFC 10816

The Formation History of Andromeda's Extended Metal-Poor Halo

We propose deep ACS imaging in the outer spheroid of the Andromeda
galaxy, in order to measure the star formation history of its true
halo. For the past 20 years, nearly all studies of the Andromeda
"halo" were focused on the spheroid within 30 kpc of the galaxy's
center, a region now known to host significant substructure and
populations with high metallicity and intermediate ages. However, two
groups have recently discovered an extended metal-poor halo beyond 30
kpc; this population is distinct in its surface-brightness profile,
abundance distribution, and kinematics. In earlier cycles, we obtained
deep images of the inner spheroid {11 kpc on the minor axis}, outer
disk {25 kpc on the major axis}, and giant tidal stream, yielding the
complete star formation history in each field. We now propose deep ACS
imaging of 4 fields bracketing this 30 kpc transition point in the
spheroid, so that the inner spheroid and the extended halo populations
can be disentangled, enabling a reconstruction of the star formation
history in the halo. A wide age distribution in the halo, as found in
the inner spheroid, would imply the halo was assembled through ongoing
accretion of satellite galaxies, while a uniformly old population
would be a strong indication that the halo was formed during the early
rapid collapse of the Andromeda proto-galaxy.

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.

NIC3/ACS/WFC 10921

Tangential Velocities of Objects in the Orion Nebula and Locating the
Embedded Outflow Sources.

The Orion Nebula is arguably the Rosetta Stone for studying a very
young star cluster and how the radiation and outflowing plasma from
its stars interact with ambient material. It has been the subject of
numerous HST imaging studies, which means that there is good
opportunity for determining tangential velocities by obtaining second
epoch images during Cycle 15, which may be the last cycle for which
the WFPC2 is available. These velocities in the plane-of-the-sky will
allow us to determine the patterns of outflow from micro-jets smaller
than the Solar System to jet driven shocks more than a parsec from
their sources. Combined with radial velocities, we'll obtain spatial
velocities, which are critical to determining where the embedded
sources are located that produce the numerous HH objects coming from
the Orion-S and BN-KL regions. We'll also be able to determine the
physics that is operating in the LL Ori type of outflows {where a
bipolar jet is being distorted by a slow wind coming from the nebula}.
We will also be able to search for runaway stars caused by the
disintegration of young multiple-star systems. All of this is possible
because the long-time base of the WFPC2 and ACS observations allow a
new level of astrometric precision to be obtained and to be done
efficiently by making coordinated parallel observations with all
images.

WFPC2 10744

WFPC2 Cycle 14 Decontaminations and Associated Observations

This proposal is for the WFPC2 decontamination. Also included are
instrument monitors tied to decontamination: photometric stability
check, focus monitor, pre- and post-decontamination 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:

10470 - GSacq (2,3,2) failed due to search radius limit exceeded on FGS 3

GSacq (2,3,2) scheduled at 18:47:51 failed. 486 ESB a05, Exceeded SRL.
OBAD 1 RSS = 5641.51 OBAD 2 RSS = 10.63 MAP @ next AOS (19:43:39) RSS
= 17.76

REacq scheduled at 20:24:54 failed with the same indications as the
GSacq including a 486 STB a05 message Reacq(2,3,2) OBAD 1 RSS 3845.000
OBAD 2 RSS 8.07 MAP RSS 20.35

REacq(2,3,2) scheduled at 22:03:20 also failed with the same mnemonics
and 486 ESB message. OBAD 1 RSS 2705.13 OBAD 2 RSS 7.81 No MAP
scheduled

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 09 08
FGS REacq 05 03
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)