Daily Report #4803

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** #4803

PERIOD COVERED: 5am March 3 - 5am March 4, 2009 (DOY
*************************** 062/1000z-063/1000z)

OBSERVATIONS SCHEDULED

ACS/SBC 11980

Deep FUV Imaging of Cooling Flow Clusters

We propose to take deep ACS FUV images of a carefully selected sample
of 19 bright central galaxies in nearby galaxy clusters. This program
is the last critical element of a comprehensive investigation of the
impact of stellar and AGN feedback on the local galaxy cluster
environment. The HST images will complement new, high-resolution,
Halpha images obtained with the recently commissioned
Maryland-Magellan Tunable Filter (MMTF) on the Baade 6.5m telescope,
archival Chandra, VLA, and GALEX data, and on-going H2/NIR
observations. The MMTF data have revealed unsuspected filamentary
complexes in several systems. The GALEX data often show hints of
extended NUV and FUV emission on a similar scale, but their poor
spatial resolution prevents meaningful comparison with the MMTF data.
The HST data will provide this much needed gain in resolution. The
combined radio-H2-Halpha-FUV-X-ray dataset will allow us to derive
with unprecedented precision the role of the AGN, hot stars, shocks,
and relativistic particles on the excitation and thermodynamics of the
multi-phase intracluster and interstellar media in these systems. This
is an important question since the formation and evolution of most
cluster galaxies have likely been affected by these processes.

WFPC2 11972

Investigating the Early Solar System with Distant Comet Nuclei

We propose 85 orbits of imaging observations with the WFPC2 to get
nucleus size estimates for 8 well observed dynamically new and
long-period comets at large distances from the sun when their activity
levels are low. This will increase the sample of these nucleus sizes
by nearly 50%, but will more than double the selection of comets for
which we can run thermal models. Small icy bodies are the best
preserved remnants of planet formation, and we have recently found
that observationally constrained thermal models can distinguish
differences in microphysical properties of comet nuclei. The new HST
data will enable the first exploration of physical conditions in
different regions of the early solar nebula.

WFPC2 11981

FUV Imaging Survey of Galactic Open Clusters

We propose a WFPC2 FUV imaging survey of 6 Galactic open clusters with
ages ranging from 1 Myr to 300 Myr complemented with NUV/optical
imaging of the same fields. No such survey has ever been attempted
before in the FUV at the resolution of WFPC2 (indeed, no WFPC2 FUV
images of any Galactic open cluster exist in the HST archive) and,
since WFPC2 will be retired in SM4 and none of the other HST
instruments can do FUV imaging of bright objects, this is the last
chance to do such a survey before another UV telescope is launched.
This survey will provide a new perspective on young/intermediate age
Galactic clusters and a key template for the study of star formation
at high redshift, where the intensity peak we observe in the
optical/NIR from Earth is located in the FUV in its rest frame. For
clusters still associated with an H II region, UV imaging maps the
continuum emission of the ionized gas and the radiation scattered by
background dust and, combined with optical nebular images, can be used
to determine the 3-D structure of the H II region. For all young
clusters, FUV+NUV+optical photometry can be used to study the UV
excesses of T-Tauri stars. For clusters older than ~40 Myr, the same
photometric combination is the easiest method to detect companion
white dwarfs which are invisible using only the optical and NIR. WFPC2
is also an excellent instrument to discover close companions around
bright stars and improve our knowledge of their multiplicity fraction.
Finally, for all clusters, the combination of high-spatial-resolution
UV and optical photometry can be used to simultaneously measure the
temperature, extinction, extinction law, distance, and existence of
companions (resolved and unresolved) and, thus, produce clean HR
diagrams with resolved cluster membership and much-reduced systematic
uncertainties.

WFPC2 11983

An Imaging Survey of Protoplanetary Disks and Brown Dwarfs in the
Chamaeleon I region

We propose to carry out a HST/WFPC2 survey of young brown dwarfs,
Class I and Class II sources in the Chamaelon I region, one of the
best-studied star-forming regions, in order to investigate the link
between disk evolution and the formation of substellar-mass objects.
We will use deep broad-band imaging in the I and z-equivalent HST
bands to unveil the unknown population of substellar binary
companions, down to a few Jupiter masses for separations of a few tens
of AU. We will also perform narrow-band imaging to directly detect
accreting circumstellar disks and jets around brown dwarfs, Class-I
and class-II objects. Chamaelon I is nearly coeaval of Orion (~1-2Myr)
but at ~1/3 its distance, allowing 3x higher resolution and 10x more
flux for comparable objects. Unlike Orion, low-mass objects and
protoplanetary disks in Chamaeleon I have been extensively studied
with Spitzer, but not yet with the HST. The Chamaeleon I region is an
ideal HST target, as it lies in the CVZ of the HST and therefore it is
easily accessible any time of the year with long orbits.

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************** 05****************** 05
FGS REAcq************** 09****************** 09
OBAD with Maneuver **** 30****************** 30

SIGNIFICANT EVENTS: (None)