HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #4962
PERIOD
COVERED: 5am October 29 - 5am October 30, 2009 (DOY 302/09:00z-303/09:00z)
OBSERVATIONS
SCHEDULED
ACS/WFC
11689
Direct
Observations of Dark Matter from a Second Bullet: The Spectacular
Abell
2744
Vigorous
cluster mergers provide a unique opportunity to directly "see"
dark
matter and to probe its properties through the analysis of the
segregation
of the baryonic and non-baryonic components. This is
accomplished
through detailed comparison of the mass distributions as
traced
by X-ray emitting gas and by gravitational lensing. This
condition
is rare and so far only one cluster has met these
requirements,
the so-called "bullet" cluster, producing exciting results
and
placing constraints to the properties of dark matter. These
constraints
have a broad impact on models for formation of structure and
on
galaxy evolution. This multi-wavelength analysis has the potential
confront
alternative gravity models such as MOND. Therefore, it is
crucial
to find new bullet clusters to corroborate and improve
previous
measurements. This is the most direct way to constrain dark
matter
properties and A2744 is ideal for corroborating this study since
it
maximizes all the requirements for this analysis. Here, we propose to
carry
out such analysis through combined ACS and Chandra observations of
the
cluster merger Abell 2744.
COS/NUV
11900
NUV
Internal/External Wavelength Scale Monitor
This
program monitors the offsets between the wavelength scale set by
the
internal wavecal versus that defined by absorption lines in external
targets.
This is accomplished by observing two external radial velocity
standard
targets: HD187691 with G225M and G285M and HD6655 with G285M
and
G230L. The two standard targets have little flux in the wavelength
range
covered by G185M and so Feige 48 (sdO) is observed with this
grating.
Both Feige 48 and HD6655 are also observed in SMOV. The
cenwaves
observed in this program are a subset of the ones used during
Cycle
17. Observing all cenwaves would require a considerably larger
number
of orbits. Constraints on scheduling of each target are placed so
that
each target is observed once every ~2-3 months. Observing the three
targets
every month would also require a considerably larger number of
orbits.
NIC2/WFC3/IR
11548
Infrared
Imaging of Protostars in the Orion A Cloud: The Role of
Environment
in Star Formation
We
propose NICMOS and WFC3/IR observations of a sample of 252 protostars
identified
in the Orion A cloud with the Spitzer Space Telescope. These
observations
will image the scattered light escaping the protostellar
envelopes,
providing information on the shapes of outflow cavities, the
inclinations
of the protostars, and the overall morphologies of the
envelopes.
In addition, we ask for Spitzer time to obtain 55-95 micron
spectra
of 75 of the protostars. Combining these new data with existing
3.6
to 70 micron photometry and forthcoming 5-40 micron spectra measured
with
the Spitzer Space Telescope, we will determine the physical
properties
of the protostars such as envelope density, luminosity,
infall
rate, and outflow cavity opening angle. By examining how these
properties
vary with stellar density (i.e. clusters vs. groups vs.
isolation)
and the properties of the surrounding molecular cloud; we can
directly
measure how the surrounding environment influences protostellar
evolution,
and consequently, the formation of stars and planetary
systems.
Ultimately, this data will guide the development of a theory of
protostellar
evolution.
STIS/CCD
11606
Dynamical
Hypermassive Black Hole Masses
We
will use STIS spectra to derive the masses of 5 hypermassive black
holes
(HMBHs). From the observed scaling relations defined by less
massive
spheroids, these objects are expected to reside at the nuclei of
host
galaxies with stellar velocity dispersions greater than 320 km/s.
These
5 targets have confirmed regular gas distributions on the scales
of
the black hole sphere of influence. It is essential that the sphere
of
influence is resolved for accurate determinations of black hole mass
(0.1").
These scales cannot be effectively observed from the ground.
Only
two HMBHs have had their masses modeled so far; it is impossible to
draw
any general conclusions about the connections between HMBH mass and
their
massive host galaxies. With these 5 targets we will determine
whether
these HMBHs deviate from the scaling relations defined by less
massive
spheroids. A larger sample will allow us to firmly anchor the
high
mass end of the correlation between black hole mass and stellar
velocity
dispersion, and other scaling relations. Therefore we are also
conducting
a SNAPshot program with which we expect to detect a further
24
HMBH candidates for STIS observation in future cycles. At the
completion
of this project we will have populated the high mass end of
the
scaling relations with the sample sizes enjoyed by less massive
spheroids.
STIS/CCD
11653
SAINTS
- Supernova 1987A INTensive Survey
SAINTS
is a program to observe SN 1987A, the brightest supernova since
1604,
as it matures into the youngest supernova remnant at age 21. HST
is
the essential tool for resolving SN1987A's many physical components.
A
violent encounter is underway between the fastest-moving debris and
the
circumstellar ring: shocks excite "hotspots." Radio, optical,
infrared
and X-ray fluxes have been rising rapidly: we have organized
Australia
Telescope, HST, VLT, Spitzer, and Chandra observations to
understand
the several emission mechanisms at work. Photons from the
shocked
ring will excite previously invisible gas outside the ring,
revealing
the true extent of the mass loss that preceded the explosion
of
Sanduleak -69 202. This will help test ideas for the progenitor of SN
1987A.
The inner debris, excited by radioactive isotopes from the
explosion,
is now resolved and seen to be aspherical, providing direct
evidence
on the shape of the explosion itself. Questions about SN 1987A
remain
unanswered. A rich and unbroken data set from SAINTS will help
answer
these central questions and will build an archive for the future
to
help answer questions we have not yet thought to ask.
STIS/CCD
11844
CCD
Dark Monitor Part 1
The
purpose of this proposal is to monitor the darks for the STIS CCD.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
The
purpose of this proposal is to monitor the bias in the 1x1, 1x2,
2x1,
and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up
high-S/N
superbiases and track the evolution of hot columns.
WFC3/UV/ACS/WFC
11688
Exploring
the Bottom End of the White Dwarf Cooling Sequence in the Open
Cluster
NGC6819
The
recent discovery by our group of an unexpectedly bright end of the
white-dwarf
(WD) luminosity function (LF) of the metal-rich, old open
cluster
NGC 6791 casts serious doubts on our understanding of the
physical
process which rules the formation and the cooling of WDs. It is
clear
at this point that the theory badly needs more observations. Here
we
propose WFC3/UVIS and ACS/WFC HST observations reaching the bottom
end
of the WD LF, for the first time in a solar-metallicity,
2.5-Gyr-old,
populous open cluster: NGC 6819.
WFC3/UVIS
11565
A
Search for Astrometric Companions to Very Low-Mass, Population II
Stars
We
propose to carry out a Snapshot search for astrometric companions in
a
subsample of very low-mass, halo subdwarfs identified within 120
parsecs
of the Sun. These ultra-cool M subdwarfs are local
representatives
of the lowest-mass H burning objects from the Galactic
Population
II. The expected 3-4 astrometric doubles that will be
discovered
will be invaluable in that they will be the first systems
from
which gravitational masses of metal-poor stars at the bottom of the
main
sequence can be directly measured.
WFC3/UVIS
11657
The
Population of Compact Planetary Nebulae in the Galactic Disk
We
propose to secure narrow- and broad-band images of compact planetary
nebulae
(PNe) in the Galactic Disk to study the missing link of the
early
phases of post-AGB evolution. Ejected AGB envelopes become PNe
when
the gas is ionized. PNe expand, and, when large enough, can be
studied
in detail from the ground. In the interim, only the HST
capabilities
can resolve their size, morphology, and central stars. Our
proposed
observations will be the basis for a systematic study of the
onset
of morphology. Dust properties of the proposed targets will be
available
through approved Spitzer/IRS spectra, and so will the
abundances
of the alpha- elements. We will be able thus to explore the
interconnection
of morphology, dust grains, stellar evolution, and
populations.
The target selection is suitable to explore the nebular and
stellar
properties across the galactic disk, and to set constraints on
the
galactic evolutionary models through the analysis of metallicity and
population
gradients.
WFC3/UVIS
11714
Snapshot
Survey for Planetary Nebulae in Local Group Globular Clusters
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, four, 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 outside the Milky Way. These clusters, some of
which
may be much younger than their counterparts in our galaxy, 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. This proposal continues a WFPC2 program started in Cycle
16,
but with the more powerful WFC3. As a by-product, the survey will
also
produce color-magnitude diagrams for numerous clusters for the
first
time, reaching down to the horizontal branch.
WFC3/UVIS
11905
WFC3
UVIS CCD Daily Monitor
The
behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame,
four-amp bias and dark frames. A smaller set of 2Kx4K
subarray
biases are acquired at less frequent intervals throughout the
cycle
to support subarray science observations. The internals from this
proposal,
along with those from the anneal procedure (Proposal 11909),
will
be used to generate the necessary superbias and superdark reference
files
for the calibration pipeline (CDBS).
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
11
11
FGS
REAcq
06
06
OBAD
with Maneuver
06
06
SIGNIFICANT
EVENTS: (None)