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Daily Report #5030



 
 
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Old February 10th 10, 06:24 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5030

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5030

PERIOD COVERED: 5am February 09 - 5am February 10, 2010 (DOY 040/10:00z-041/10:00z)

OBSERVATIONS SCHEDULED

S/C 12046

COS FUV DCE Memory Dump

Whenever the FUV detector high voltage is on, count rate and current
draw information is collected, monitored, and saved to DCE memory.
Every 10 msec the detector samples the currents from the HV power
supplies (HVIA, HVIB) and the AUX power supply (AUXI). The last 1000
samples are saved in memory, along with a histogram of the number of
occurrences of each current value.

In the case of a HV transient (known as a "crackle" on FUSE), where
one of these currents exceeds a preset threshold for a persistence
time, the HV will shut down, and the DCE memory will be dumped and
examined as part of the recovery procedure. However, if the current
exceeds the threshold for less than the persistence time (a
"mini-crackle" in FUSE parlance), there is no way to know without
dumping DCE memory. By dumping and examining the histograms regularly,
we will be able to monitor any changes in the rate of "mini-crackles"
and thus learn something about the state of the detector.

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/ACS/IR 11563

Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to
0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields

The first generations of galaxies were assembled around redshifts
z~7-10+, just 500-800 Myr after recombination, in the heart of the
reionization of the universe. We know very little about galaxies in
this period. Despite great effort with HST and other telescopes, less
than ~15 galaxies have been reliably detected so far at z7,
contrasting with the ~1000 galaxies detected to date at z~6, just
200-400 Myr later, near the end of the reionization epoch. WFC3 IR can
dramatically change this situation, enabling derivation of the galaxy
luminosity function and its shape at z~7-8 to well below L*,
measurement of the UV luminosity density at z~7-8 and z~8-9, and
estimates of the contribution of galaxies to reionization at these
epochs, as well as characterization of their properties (sizes,
structure, colors). A quantitative leap in our understanding of early
galaxies, and the timescales of their buildup, requires a total sample
of ~100 galaxies at z~7-8 to ~29 AB mag. We can achieve this with 192
WFC3 IR orbits on three disjoint fields (minimizing cosmic variance):
the HUDF and the two nearby deep fields of the HUDF05. Our program
uses three WFC3 IR filters, and leverages over 600 orbits of existing
ACS data, to identify, with low contamination, a large sample of over
100 objects at z~7-8, a very useful sample of ~23 at z~8-9, and limits
at z~10. By careful placement of the WFC3 IR and parallel ACS
pointings, we also enhance the optical ACS imaging on the HUDF and a
HUDF05 field. We stress (1) the need to go deep, which is paramount to
define L*, the shape, and the slope alpha of the luminosity function
(LF) at these high redshifts; and (2) the far superior performance of
our strategy, compared with the use of strong lensing clusters, in
detecting significant samples of faint z~7-8 galaxies to derive their
luminosity function and UV ionizing flux. Our recent z~7.4 NICMOS
results show that wide-area IR surveys, even of GOODS-like depth,
simply do not reach faint enough at z~7-9 to meet the LF and UV flux
objectives. In the spirit of the HDF and the HUDF, we will waive any
proprietary period, and will also deliver the reduced data to STScI.
The proposed data will provide a Legacy resource of great value for a
wide range of archival science investigations of galaxies at redshifts
z~2-9. The data are likely to remain the deepest IR/optical images
until JWST is launched, and will provide sources for spectroscopic
follow up by JWST, ALMA and EVLA.

WFC3/ACS/IR 11597

Spectroscopy of IR-Selected Galaxy Clusters at 1 z 1.5

We propose to obtain WFC3 G141 and G102 slitless spectroscopy of
galaxy clusters at 1 z 1.5 that were selected from the IRAC survey
of the Bootes NDWFS field. Our IRAC survey contains the largest sample
of spectroscopically confirmed clusters at z 1. The WFC3 grism data
will measure H-alpha to determine SFR, and fit models to the low
resolution continua to determine stellar population histories for the
brighter cluster members, and redshifts for the red galaxies too faint
for ground-based optical spectroscopy.

WFC3/IR 11666

Chilly Pairs: A Search for the Latest-type Brown Dwarf Binaries and
the Prototype Y Dwarf

We propose to use HST/NICMOS to image a sample of 27 of the nearest (
20 pc) and lowest luminosity T-type brown dwarfs in order to identify
and characterize new very low mass binary systems. Only 3 late-type T
dwarf binaries have been found to date, despite that fact that these
systems are critical benchmarks for evolutionary and atmospheric
models at the lowest masses. They are also the most likely systems to
harbor Y dwarf companions, an as yet unpopulated putative class of
very cold (T 600 K) brown dwarfs. Our proposed program will more
than double the number of T5-T9 dwarfs imaged at high resolution, with
an anticipated yield of ~5 new binaries with initial characterization
of component spectral types. We will be able to probe separations
sufficient to identify systems suitable for astrometric orbit and
dynamical mass measurements. We also expect one of our discoveries to
contain the first Y-type brown dwarf. Our proposed program complements
and augments ongoing ground-based adaptive optics surveys and provides
pathway science for JWST.

WFC3/IR 12051

Cross Calibration of NICMOS and WFC3 in the Low-Count-Rate Regime

NICMOS has played a key role in probing the deep near infrared regime
for a decade. It has been the only instrument available to observe
faint objects in the near infrared that are not observable from the
ground. However, the calibration of NICMOS has turned out to be
difficult in the low-count-rate regime. The NICMOS calibration team
has extrapolated a power-law to describe the apparent non-linearity in
the NICMOS detectors from measurements at ~50-5000 ADU/s to flux
counts around 0.1-1 ADU/s. Precise measurements of faint objects (such
as SNe Ia at high redshift) require us to reduce the uncertainties
from this extrapolation. Here we propose to determine the absolute
zeropoint for faint objects by cross-calibrating the WFC3 and NICMOS
detectors in observations of early type galaxies at redshifts z1.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark
current image scaled by desired exposure time. Therefore, dark current
images must be collected using all sample sequences that will be used
in science observations. These observations will be used to monitor
changes in the dark current of the WFC3-IR channel on a day-to-day
basis, and to build calibration dark current ramps for each of the
sample sequences to be used by Gos in Cycle 17. For each sample
sequence/array size combination, a median ramp will be created and
delivered to the calibration database system (CDBS).

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 11908

Cycle 17: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the
UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially found via an unexpected bowtie-shaped feature in flatfield
ratios, subsequent lab tests on similar e2v devices have since shown
that it is also present as simply an overall offset across the entire
CCD, i.e., a QE offset without any discernable pattern. These lab
tests have further revealed that overexposing the detector to count
levels several times full well fills the traps and effectively
neutralizes the bowtie. Each visit in this proposal acquires a set of
three 3x3 binned internal flatfields: the first unsaturated image will
be used to detect any bowtie, the second, highly exposed image will
neutralize the bowtie if it is present, and the final image will allow
for verification that the bowtie is gone.

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 03 03

SIGNIFICANT EVENTS: (None)


 




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