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Daily Report #4962



 
 
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Old October 30th 09, 08:58 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4962

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)


 




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