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3\06 HST Daily Rpt No 3314
Part 1 of 3

 HUBBLE SPACE TELESCOPE
  DAILY REPORT # 3314

PERIOD COVERED: DOY 65

OBSERVATIONS SCHEDULED

NICMOS 8791

NICMOS Post-SAA calibration - CR Persistence Part 2

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.

WF/PC-2 9142

The Structure and Physics of Extragalactic Jets.

The WF/PC-2 was used to perform an ongoing investigation into the 
physics of jets. It is proposed to obtain polarimetry of the jets of 
3C 264 and 3C 78.

NICMOS 9386

Infrared Photometry of a Statistically Significant Sample of KBOs

While the discovery rate of Kuiper Belt objects is accelerating, the 
physical study of this new region of the solar system has been slowed 
by a lack of basic astrophysical data. Photometric observations of the 
majority of the more than 400 known KBOs and Centaurs are rudimentary 
and incomplete, particularly in the infrared. The multicolor 
optical-infrared photometry that exists for a small subset of KBOs 
often shows significant discrepancies between observations by 
different observers. Their intrinsic faintness puts them at the 
practical limits of ground-based systems. In July 2001 we began what 
will be the largest uniform sample of optical photometry of KBOs with 
a WFPC2 SNAPSHOT program that will perform accurate photometry at V, 
R, and I on a sample of up to 150 targets. We seek to greatly enhance 
the value of this survey by obtaining J and H photometry on the same 
sample using NICMOS. Combined optical and infrared broad band
photometry is a far more powerful tool for physical studies than is 
either alone. Our sample includes objects that will be observed at 
thermal infrared wavelengths by SIRTF and will be used with those data 
to derive the first accurate diameters, albedos, and surface 
properties for a large sample of KBOs.

STIS/CCD 9432

The Radio-Loud BAL QSO PKS 1004+13: A Key to Understanding QSO 
Outflows?

Accretion and outflows drive astrophysical engines on many scales. In 
powerful QSOs, broad absorption lines {BALs} reveal partially-ionized 
outflows to ~0.1c.  What is the geometry of the flow, its origin, the 
driving mechanism? Why are the most extreme outflows always seen in 
radio-weak QSOs? Such basic questions remain unanswered. Plausibly, 
radiation pressure can drive an equatorial wind off the dusty torus or 
outer accretion disk. Are BAL QSOs seen nearly edge-on, as this 
scenario requires? We don't know because there is no good inclination
indicator for these generally radio-weak QSOs. The bright, 
low-redshift QSO PKS 1004+13 may be a valuable exception. Its dominant 
radio lobes imply a near edge-on view, while low SNR IUE spectra 
suggest it is a BAL QSO. Indirect indications that it's a BAL QSO are: 
very weak soft X-ray flux, high scattering polarization, and unusually 
weak ionO3. It also shows clear high-ionization non-BAL absorption 
with partial continuum coverage. We propose high quality UV 
spectroscopy to confirm its BAL QSO identity. PKS 1004+13 would be 
only the second known BAL QSO with powerful radio jets, hence known 
inclination, providing a clear test of the outflow geometry, and the 
only such object at low redshift, allowing high SNR, high spatial 
resolution followup.

ACS 9440

The Composition of Io's Pele Plume

We propose to determine the composition of Io's largest volcanic 
plume, Pele, with unprecedented accuracy. This will give us new 
constraints on the temperatures, pressures, and magma composition of 
this volcano, and thus an improved window into Io's interior. We will 
use the proven Jupiter transit spectroscopy technique, which resulted 
in the discovery of S_2 gas in the Pele plume, but will use exposures 
that are 4 times longer than in the discovery observations. This will 
allow us to accurately measure plume SO_2 abundances, seen only with 
low S/N in the discovery observations, and possibly SO, in addition to 
S_2, and gives the chance to discover other, currently unknown, plume 
components. We will also use ACS to obtain UV and visible images of 
the Pele plume in reflected light prior to Jupiter transit, to 
constrain the dust abundance and particle size in the plume. This will 
allow refined estimates of plume dust/gas ratios and resurfacing 
rates. We will repeat the observations four times to build up S/N to 
even higher levels, and to look for time variability in both dust and 
gas abundance and chemistry.

ACS 9450

The lensing galaxy of JVAS B0218+357: determination of H_0

Much effort has been devoted to estimating Hubble's constant H_0 using
observations of very nearby objects. Gravitational lensing time delays 
offer potentially the most accurate method for determining H_0 using 
observations on cosmological scales; it is a very clean method in that 
little complicated astrophysics is involved, and it is a single--step 
method compared to the traditional multi--step distance ladder. The 
major problem with most such determinations in the past has been 
systematic errors due to uncertainties in the lens mass model, leading 
to 20 Einstein-ring lens system, is the one system for which these 
systematic uncertainties can be reduced very substantially, and in 
particular is unique in that the modeling systematics can be reduced 
to the level of the uncertainties in the measurement of the time 
delay. The only requirement left is to be able accurately to locate 
the center of the lensing galaxy. We propose an extremely deep ACS 
image in I-band of this system for this purpose; the prize is a robust 
5 {lens mass model}. We have conducted simulations to estimate the 
necessary S:N ratio in an ACS observation in order to be able to 
achieve a successful deconvolution of the lens galaxy and lensed 
images with the required accuracy.

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