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Daily Report #4514



 
 
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Old December 27th 07, 03:33 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4514

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** # 4514

PERIOD COVERED: UT December 26, 2007 (DOY 360)

OBSERVATIONS SCHEDULED

ACS/SBC 11145

Probing the Planet Forming Region of T Tauri Stars in Chamaeleon

By studying the inner, planet-forming regions of circumstellar disks
around low-mass pre- main sequence stars we can refine theories of
giant planet formation and develop timescales for the evolution of
disks and their planets. Spitzer infrared observations of T Tauri
stars in the Chamaeleon star-forming region have given us an
unprecedented look at dust evolution in young objects. However,
despite this ground breaking progress in studying the dust in young
disks, the gas properties of the inner disk remain essentially
unknown. Using ACS on HST, we propose to measure the H_2 emission
originating in the innermost disk regions of classical T Tauri stars
in different stages of evolution with the objective of revealing the
timescales of gas dissipation and its relationship to dust evolution.
This proposal is part of a comprehensive effort with approved programs
on Spitzer, Gemini, and Magellan that aim to characterize the state of
gas and dust in disks where planets may already have formed.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that
prediction. It is, however, a prediction of extrasolar planetary
system architecture as yet untested by direct observation for main
sequence stars other than the Sun. To provide such a test, we propose
to carry out FGS astrometric studies on four stars hosting seven
companions. Our understanding of the planet formation process will
grow as we match not only system architecture, but formed planet mass
and true distance from the primary with host star characteristics for
a wide variety of host stars and exoplanet masses. We propose that a
series of FGS astrometric observations with demonstrated 1 millisecond
of arc per- observation precision can establish the degree of
coplanarity and component true masses for four extrasolar systems: HD
202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 = mu
Arae {planet+planet}, and HD 222404AB = gamma Cephei {planet+star}. In
each case the companion is identified as such by assuming that the
minimum mass is the actual mass. For the last target, a known stellar
binary system, the companion orbit is stable only if coplanar with the
AB binary orbit.

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

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 11040

Geometric Distortion / Astrometry Closeout

These observations will serve as a final characterization of the
geometric distortion and astrometric calibration. The Omega-Cen inner
calibration field is used. Filters F300W, F555W, and F814W are
observed at 5 roll angles spanning 180 degrees; F218W is observed at a
single roll angle.

WFPC2 11083

The Structure, Formation and Evolution of Galactic Cores and Nuclei

A surprising result has emerged from the ACS Virgo Cluster Survey
{ACSVCS}, a program to obtain ACS/WFC gz imaging for a large, unbiased
sample of 100 early-type galaxies in the Virgo Cluster. On
subarcsecond scales {i.e., 0.1"-1"}, the HST brightness profiles vary
systematically from the brightest giants {which have nearly constant
surface brightness cores} to the faintest dwarfs {which have compact
stellar nuclei}. Remarkably, the fraction of galaxy mass contributed
by the nuclei in the faint galaxies is identical to that contributed
by supermassive black holes in the bright galaxies {0.2%}. These
findings strongly suggest that a single mechanism is responsible for
both types of Central Massive Object: most likely internally or
externally modulated gas inflows that feed central black holes or lead
to the formation of "nuclear star clusters". Understanding the history
of gas accretion, star formation and chemical enrichment on
subarcsecond scales has thus emerged as the single most pressing
question in the study of nearby galactic nuclei, either active or
quiescent. We propose an ambitious HST program {199 orbits} that
constitutes the next, obvious step forward: high-resolution,
ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging for the
complete ACSVCS sample. By capitalizing on HST's unique ability to
provide high-resolution images with a sharp and stable PSF at UV and
IR wavelengths, we will leverage the existing optical HST data to
obtain the most complete picture currently possible for the history of
star formation and chemical enrichment on these small scales. Equally
important, this program will lead to a significant improvement in the
measured structural parameters and density distributions for the
stellar nuclei and the underlying galaxies, and provide a sensitive
measure of "frosting" by young stars in the galaxy cores. By virtue of
its superb image quality and stable PSF, NICMOS is the sole instrument
capable of the IR observations proposed here. In the case of the WFPC2
observations, high-resolution UV imaging { 0.1"} is a capability
unique to HST, yet one that could be lost at anytime.

WFPC2 11218

Snapshot Survey for Planetary Nebulae in Globular Clusters of the
Local Group

Planetary nebulae {PNe} in globular clusters {GCs} raise a number of
interesting issues related to stellar and galactic evolution. The
number of PNe known in Milky Way GCs, 4, is surprisingly low if one
assumes that all stars pass through a PN stage. However, it is likely
that the remnants of stars now evolving in Galactic GCs leave the AGB
so slowly that any ejected nebula dissipates long before the star
becomes hot enough to ionize it. Thus there should not be ANY PNe in
Milky Way GCs--but there are four! It has been suggested that these
PNe are the result of mergers of binary stars within GCs, i.e., that
they are descendants of blue stragglers. The frequency of occurrence
of PNe in external galaxies poses more questions, because it shows a
range of almost an order of magnitude. I propose a Snapshot survey
aimed at discovering PNe in the GC systems of Local Group galaxies
more distant than the Magellanic Clouds. These clusters, some of which
may be much younger than their counterparts in the Milky Way, might
contain many more PNe than those of our own galaxy. I will use the
standard technique of emission-line and continuum imaging, which
easily discloses PNe.

WFPC2 11339

A deep observation of NGC4261: understanding its unique X-ray source
population, gas morphology, and jet properties

The nearby early-type galaxy NGC4261 reveals strikingly asymmetric
distributions of X-ray sources as seen with Chandra, and globular
clusters (GC) as seen in the optical band. To address the link between
these populations based on their spatial correlation, luminosity
function and spectral properties, and to investigate the possibility
that this effect is due to the galaxy's merger history, we propose a
100ksec Chandra ACIS-S3 exposure, which will detect X-ray sources down
to typical LMXB luminosities (Lx~5E37 erg/s), and HST-WFPC2
observations to obtain a deep census of the GC population over the
whole galaxy. These data will also allow a detailed study of its
complex gaseous component, and provide information on the unique
two-sided X-ray jet.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11122 - GSacq (2,3,3) resulted in Fine Lock Back-up (2,0,2) using FGS
2

At acquisition of Signal (360/19:28:15), GSAcq (2,3,3) scheduled from
360/19:23:54 - 19:31:08 had resulted in Fine Lock Back-up (2,0,2)
using FGS 2. Received QF3STOPF & QSTOP flags. No 486 ESB messages were
received. Pre-acquisition OBAD #1 values: V1 748.74, V2 -1591.73, V3
754.26, RSS 1913.93. Pre-acquisition OBAD #2 values: V1 6.66, V2
-1.76, V3 6.88, RSS 9.74.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

*********************** SCHEDULED***** SUCCESSFUL

FGS GSacq************** 07**************** 07
FGS REacq************** 08**************** 08
OBAD with Maneuver **** 30**************** 30

SIGNIFICANT EVENTS: (None)


 




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