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Daily Report #4952



 
 
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Old October 16th 09, 04:10 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4952

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #4952

PERIOD COVERED: 5am October 15 - 5am October 16, 2009 (DOY 288/09:00z-289/09:00z)

OBSERVATIONS SCHEDULED

ACS/WFC 11840

Identifying the Host Galaxies for Optically Dark Gamma-ray Bursts

We propose to use the high spatial resolution of Chandra to obtain
precise positions for a sample of Gamma-Ray Bursts (GRBs) with no
optical afterglows, where the optical light is suppressed relative to
the X-ray flux. These bursts are likely to be highly obscured and may
have different environments from the optically bright GRBs. Our
Chandra observations will (unlike Swift XRT positions) allow for the
unique identification of a host galaxy. To locate these host galaxies
we will follow up our Chandra positions with deep optical and IR
observations with HST. The ultimate aim is to understand any
differences between the host galaxies of optically dark and bright
GRBs, and how these affect the use of GRBs as tracers of starformation
and galaxy evolution at high redshift.

ACS/WFC3 11599

Distances of Planetary Nebulae from SNAPshots of Resolved Companions

Reliable distances to individual planetary nebulae (PNe) in the Milky
Way are needed to advance our understanding of their spatial
distribution, birthrates, influence on galactic chemistry, and the
luminosities and evolutionary states of their central stars (CSPN).
Few PNe have good distances, however. One of the best ways to remedy
this problem is to find resolved physical companions to the CSPN and
measure their distances by photometric main-sequence fitting. We have
previously used HST to identify and measure probable companions to 10
CSPN, based on angular separations and statistical arguments only. We
now propose to use HST to re-observe 48 PNe from that program for
which additional companions are possibly present. We then can use the
added criterion of common proper motion to confirm our original
candidate companions and identify new ones in cases that could not
confidently be studied before. We will image the region around each
CSPN in the V and I bands, and in some cases in the B band. Field
stars that appear close to the CSPN by chance will be revealed by
their relative proper motion during the 13+ years since our original
survey, leaving only genuine physical companions in our improved and
enlarged sample. This study will increase the number of Galactic PNe
with reliable distances by 50 percent and improve the distances to Pne
with previously known companions.

ACS/WFC3 11670

The Host Environments of Type Ia Supernovae in the SDSS Survey

The Sloan Digital Sky Survey Supernova Survey has discovered nearly
500 type Ia supernovae and created a large, unique, and uniform sample
of these cosmological tools. As part of a comprehensive study of the
supernova hosts, we propose to obtain Hubble ACS images of a large
fraction of these galaxies. Integrated colors and spectra will be
measured from the ground, but we require high-resolution HST imaging
to provide accurate morphologies and color information at the site of
the explosion. This information is essential in determining the
systematic effects of population age on type Ia supernova luminosities
and improving their reliability in measuring dark energy. Recent
studies suggest two populations of type Ia supernovae: a class that
explodes promptly after star-formation and one that is delayed by
billions of years. Measuring the star-formation rate at the site of
the supernova from colors in the HST images may be the best way to
differentiate between these classes.

COS/NUV 11896

NUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity of each NUV
grating mode to detect any changes due to contamination or other
causes.

NIC1/NIC2/NIC3 11947

Extended Dark Monitoring

This program takes a series of darks to obtain darks (including
amplifier glow, dark current, and shading profiles) for all three
cameras in the read-out sequences used in Cycle 17. A set of 12 orbits
will be observed every two months for a total of 72 orbits for a 12
month Cycle 17. This is a continuation of Cycle 16 program 11330
scaled down by ~80%.

The first orbit (Visit A0) should be scheduled in the NICMOS SMOV
after the DC Transfer Test (11406) and at least 36h before the Filter
Wheel Test (11407). Data download using fast track.

The following 28 orbits (visit A1-N2) should be scheduled AFTER the
SMOV Proposal 11407 (Filter Wheel Test). This is done in order to
monitor the dark current following an adjustment of the NCS set-point.
These visits should be executed until the final temperature is reached
during SMOV.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA Calibration - CR Persistence Part 6

This is 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
'Use After' 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 darks. 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.

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 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/IR 11618

WFC3 Observations of VeLLOs and the Youngest Star Forming Environments

The Cores-to-Disks Spitzer Legacy team has discovered a number of
extremely low luminosity sources embedded deep within nearby ( 300
pc) cores previously thought to be starless. With substellar masses,
these low luminosity sources represent either the youngest low-mass
protostars yet detected or the first embedded brown dwarfs. In either
case, they represent a new observed class of sources referred to as
VeLLOs (Very Low Luminosity Objects). We propose WFC3 F160W
observations of a small sample of these sources, to be combined with
deep ground-based observations at Ks, to address a broad set of issues
concerning VeLLOs and the environments within which they are forming.
First, the morphology of their outflow cavities will be traced,
yielding estimates of the inclinations and opening angles of the
cavities and the evolutionary stages of the VeLLOs. Second, our
observations will reveal background stars seen through the densest
regions of cores harboring these VeLLOs. The color-excesses of the
background stars will yield the highest angular resolution extinction
maps necessary to directly probe the inner density structure of these
cores, found very soon after the onset of collapse, which would
constrain the initial conditions of collapse within these isolated
environments. In addition, we will construct similar maps of the dense
pre-protostellar core L694-2 and the protostellar core B335. These
maps will provide a snapshot of the evolution of the inner density
structure of a core prior to low-mass star formation and soon
thereafter, for comparison with the inner density structure of cores
that have formed VeLLOs. Finally, these extinction maps will enable us
to determine the core "centers", or positions of peak column
densities. Comparison of these centers with the positions of the
VeLLOs may yield insight regarding potential differences between the
formation of low-mass stars and brown dwarfs.

WFC3/UV 11627

Resolving the Puzzling Nature of the Ultra-compact Binary V407 Vul

Recently, three variable stars have been identified as likely
accreting binary systems with ultra-short orbital periods of 10
minutes or less. This makes them the closest binaries known as well as
strong sources of gravitational wave emission. These objects have thus
been identified as crucial calibration sources for the LISA mission.
V407 Vul diplays a 9.5 minute period at optical and X-ray wavelengths.
Several different binary geometries have been proposed to explain this
variable star with all but one scenario identifying the 9.5 minute
period with the binary orbital period. Our time-resolved spectroscopy
and photometry from the ground revealed that the optical light is
dominated by a stationary G9 star which would be inconsistent with the
mass donor star of a compact binary. We propose ACS/HRC imaging in
order to confirm the tentative 0.03" mis-alignment we have picked up
between this G9 star and the underlying variable. Confirmation of a
spatial separation between the variable and this field star would
conclusively rule out that the G star is part of a low-inclination
binary and thus verify it as a LISA source. In addition, we propose UV
imaging that will allow us to determine the NUV luminosity of the
variable star and thereby reliably infer the distance and the nature
(and thus the gravitational wave signal) of the ultra-compact binary,
as either mass transfer or magnetic interaction powers the X-ray
source. Only HST imaging can provide rigorous proof for an
ultra-compact binary interpretation for V407 Vul and thus validate it
as LISA verification source

WFC3/UV 11906

WFC3 UVIS CCD Gain

The absolute gain of each quadrant of the WFC3 UVIS detector will be
measured for the nominal detector readout configuration and at the
on-orbit operating temperature.

WFC3/UV/IR 11664

The WFC3 Galactic Bulge Treasury Program: Populations, Formation
History, and Planets

Exploiting the full power of the Wide Field Camera 3 (WFC3), we
propose deep panchromatic imaging of four fields in the Galactic
bulge. These data will enable a sensitive dissection of its stellar
populations, using a new set of reddening-free photometric indices we
have constructed from broad-band filters across UV, optical, and
near-IR wavelengths. These indices will provide accurate temperatures
and metallicities for hundreds of thousands of individual bulge stars.
Proper motions of these stars derived from multi-epoch observations
will allow separation of pure bulge samples from foreground disk
contamination. Our catalogs of proper motions and panchromatic
photometry will support a wide range of bulge studies.

Using these photometric and astrometric tools, we will reconstruct the
detailed star-formation history as a function of position within the
bulge, and thus differentiate between rapid- and extended-formation
scenarios. We will also measure the dependence of the stellar mass
function on metallicity, revealing how the characteristic mass of star
formation varies with chemistry. Our sample of bulge stars with
accurate metallicities will include 12 candidate hosts of extrasolar
planets. Planet frequency is correlated with metallicity in the solar
neighborhood; our measurements will extend this knowledge to a remote
environment with a very distinct chemistry.

Our proposal also includes observations of six well-studied globular
and open star clusters; these observations will serve to calibrate our
photometric indices, provide empirical population templates, and
transform the theoretical isochrone libraries into the WFC3 filter
system. Besides enabling our own program, these products will provide
powerful new tools for a host of other stellar-population
investigations with HST/WFC3. We will deliver all of the products from
this Treasury Program to the community in a timely fashion.

WFC3/UVIS 11594

A WFC3 Grism Survey for Lyman Limit Absorption at z=2

We propose to conduct a spectroscopic survey of Lyman limit absorbers
at redshifts 1.8 z 2.5, using WFC3 and the G280 grism. This
proposal intends to complete an approved Cycle 15 SNAP program
(10878), which was cut short due to the ACS failure. We have selected
64 quasars at 2.3 z 2.6 from the Sloan Digital Sky Survey
Spectroscopic Quasar Sample, for which no BAL signature is found at
the QSO redshift and no strong metal absorption lines are present at z
2.3 along the lines of sight. The survey has three main

observational goals. First, we will determine the redshift frequency
dn/dz of the LLS over the column density range 16.0 log(NHI) 20.3
cm^-2. Second, we will measure the column density frequency
distribution f(N) for the partial Lyman limit systems (PLLS) over the
column density range 16.0 log(NHI) 17.5 cm^-2. Third, we will
identify those sightlines which could provide a measurement of the
primordial D/H ratio. By carrying out this survey, we can also help
place meaningful constraints on two key quantities of cosmological
relevance. First, we will estimate the amount of metals in the LLS
using the f(N), and ground based observations of metal line
transitions. Second, by determining f(N) of the PLLS, we can constrain
the amplitude of the ionizing UV background at z~2 to a greater
precision. This survey is ideal for a snapshot observing program,
because the on-object integration times are all well below 30 minutes,
and follow-up observations from the ground require minimal telescope
time due to the QSO sample being bright.

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).

WFC3/UVIS/IR 11909

UVIS Hot Pixel Anneal

The on-orbit radiation environment of WFC3 will continually generate
new hot pixels. This proposal performs the procedure required for
repairing those hot pixels in the UVIS CCDs. During an anneal, the
two-stage thermo-electric cooler (TEC) is turned off and the
four-stage TEC is used as a heater to bring the UVIS CCDs up to ~20
deg. C. As a result of the CCD warmup, a majority of the hot pixels
will be fixed; previous instruments such as WFPC2 and ACS have seen
repair rates of about 80%. Internal UVIS exposures are taken before
and after each anneal, to allow an assessment of the procedure's
effectiveness in WFC3, provide a check of bias, global dark current,
and hot pixel levels, as well as support hysteresis (bowtie)
monitoring and CDBS reference file generation. One IR dark is taken
after each anneal, to provide a check of the IR detector.

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 8 8
FGS REAcq 9 9
OBAD with Maneuver 7 7

SIGNIFICANT EVENTS: (None)


 




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