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7 May 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT        # 3357

PERIOD COVERED: DOY 126

Part 1 of 3

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. 

ACS/WFC/HRC 9075

Cosmological Parameters from Type Ia Supernovae at High Redshift.

The Advanced Camera for Surveys (WFC and HRC) was used to obtain a
Hubble diagram of Type Ia supernovae {SNe Ia} that will be of long
lasting value as a record of the expansion history of the universe.

STIS/CCD/MA1 9357

Towards a global understanding of accretion physics --, Clues from an
UV spectroscopic survey of cataclysmic variables

Accretion inflows and outflows are fundamental phenomena in a wide
variety of astrophysical environments, such as Young Stellar Objects,
galactic binaries, and AGN. Observationally, cataclysmic variables
{CVs} are particularly well suited for the study of accretion
processes. We propose to carry out a STIS UV spectroscopic snapshot
survey of CVs that fully exploits the diagnostic potential of these
objects for our understanding of accretion physics. This survey will
provide an homogenous database of accretion disc and wind outflow
spectra covering a wide range of mass transfer rates and binary
inclinations. We will analyze these spectra with state-of-the-art
accretion disc model spectra {SYNDISK}, testing our current knowledge
of the accretion disc structure, and, thereby, providing new insight
into the so far not well understood process of viscous dissipation.
We will use our parameterised wind model PYTHON for the analysis of
the radiation driven accretion disc wind spectra, assessing the
fundamental question whether the mass loss rate correlates with the
disc luminosity. In addition, our survey data will identify a number
of systems in which the white dwarf significantly contributes to the
UV flux, permitting an analysis of the impact of mass accretion on
the evolution of these compact stars. This survey will at least
double, if not triple, the number of high-quality accretion
disc / wind outflow / accreting white dwarf spectra, and we waive our
proprietary rights to permit a timely use of this database. 

NICMOS 9360

Paschen-alpha Imaging of a SIRTF-Selected Nearby Galaxy Sample

We propose to carry out a NICMOS snapshot survey in the Paschen-alpha
{PAlpha} emission line and H-band of the sample of galaxies being
observed at 3.5 -- 160 microns as part of SIRTF Nearby Galaxies
Survey {SINGS} and a related guaranteed time survey of starburst
galaxies. The PAlpha images, accessible only from HST, will be
combined with groundbased HAlpha imaging to measure the extinction in
the star-forming centers of these galaxies, and obtain robust,
extinction-corrected maps of the massive star formation rate {SFR}.
The PAlpha data by themselves will provide reliable `extinction-free'
SFRs, and a cross-calibration of the {dust--affected} HAlpha-- and
UV--based SFRs. The PAlpha--based SFR measurements will extend the
SFR-vs.-gas density law {Schmidt--law} to surface densities at least
30 times higher than what is accessible using HAlpha--based SFR
measurements alone, bridging the gap between normal galaxies and
IR--luminous starbursts. Furthermore, the combination of the HST
PAlpha images with the SIRTF images and spectra, as well as ancillary
ground--based UBVRIJHK images and GALEX UV images being obtained as
part of the SINGS project, will provide a definitive study of the
radiative transfer of starlight and dust heating in star--forming
galaxies. The processed NICMOS images will be incorporated into the
public SINGS Legacy Data Archive, to enable scores of follow-up
studies by the astronomical community at large. 

ACS 9478

The Duty Cycle of Star Formation : Far-UV imaging of the Hubble Deep
Field 

We propose deep far-UV imaging of the Hubble Deep Field {HDF} with
the ACS-SBC. Previously, we surveyed 1/5 of the HDF in the UV and now
propose to complete the area. Near- and far-UV number counts suggest
that there is a large population of UV- bright starbursts at moderate
redshifts {z<0.6}, and our proposed observations will investigate
their nature. We will measure the star formation properties of these
galaxies and their morphologies in the UV, optical, and near-IR. This
catalog of starbursts will also be important to the astronomical
community after Cycle 11 in interpreting planned SIRTF observations
of the field. We will also set strict limits on the flux escaping in
intermediate redshift {1 * Origin: SpaceBase(tm) Pt 1 -14.4- Van BC Canada 604-473-9358 (1:153/719.1)

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