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28 Mar 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT        # 3329

PERIOD COVERED: DOY 86

Part 2 of 3

ACS 9480

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground
mass provide a powerful method of directly measuring the amount and
distribution of dark matter. Several groups have recently detected
this weak lensing by large-scale structure, also called cosmic shear.
The high resolution and sensitivity of HST/ACS provide a unique
opportunity to measure cosmic shear accurately on small scales. Using
260 parallel orbits in Sloan textiti {F775W} we will measure for the
first time: beginlistosetlength sep0cm setlengthemsep0cm setlength
opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em the
skewness of the shear distribution, and em the magnification effect.
endlist Our measurements will determine the amplitude of the mass
power spectrum sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20,
and the mass density Omega_m with s/n=4. They will be done at small
angular scales where non-linear effects dominate the power spectrum,
providing a test of the gravitational instability paradigm for
structure formation. Measurements on these scales are not possible
from the ground, because of the systematic effects induced by PSF
smearing from seeing. Having many independent lines of sight reduces
the uncertainty due to cosmic variance, making parallel observations
ideal.

NICMOS 9485

Completing A Near-Infrared Search for Very Low Mass Companions to
Stars within 10 pc of the Sun

Most stars are fainter and less massive than the Sun. Nevertheless,
our knowledge of very low mass {VLM} red dwarfs and their brown dwarf
cousins is quite limited. Unknown are the true luminosity function
{LF}, multiplicity fraction, mass function, and mass-luminosity
relation for red and brown dwarfs, though they dominate the Galaxy in
both numbers and total mass. The best way to constrain these
relations is a search for faint companions to nearby stars. Such a
search has several advantages over field surveys, including greater
sensitivity to VLM objects and the availability of precise parallaxes
from which luminosities and masses can be derived. We propose to
complete our four-filter NICMOS snapshot search for companions to
stars within 10 pc. With a 10 sigma detection limit of M_J ~ 20 at 10
pc, we can detect companions between 10 and 100 AU that are at least
9 mag fainter than the empirical end of the main sequence and at
least 6.5 mag fainter than the brown dwarf Gl 229B. When completed,
our search will be the largest, most sensitive, volume-limited search
for VLM companions ever undertaken. Our four-filter search will
permit unambiguous identification of VLM-companion candidates for
follow-up observation. Together with IR speckle and deep imaging
surveys, our program will firmly establish the LF for VLM companions
at separations of 1-1000 AU and the multiplicity fraction of all
stars within 10 pc. 

STIS 9505

The Evolution of Molecular Clouds.

The combined STIS, FUSE and ground-based results will yield
information needed to understand the role of ablation in the
evolution of the central clouds. 

WFPC2 9594

WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt2/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot
pixels 

WFPC2 9598

Earth Flats

This proposal monitors flatfield stability. This proposal obtains
sequences of Earth streak flats to construct high quality flat fields
for the WFPC2 filter set. These flat fields will allow mapping of the
OTA illumination pattern and will be used in conjunction with
previous internal and external flats to generate new pipeline
superflats. These Earth flats will complement the Earth flat data
obtained during cycles 4-10. 

STIS 9606

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS 9608

CCD Bias Monitor - Part 2

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.

STIS 9623

MAMA Full Field Sensitivity Monitor & PSF Check

The purpose of this program is to monitor the sensitivity of the MAMA
detectors over the full field. This is achieved by observing globular
cluster NGC6681 once during Cycle 11. The data can be directly
compared with similar data obtained in Cycles 7, 8, 9, and 10.

ACS 9673

CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS 

WFPC2 9676

POMS Test Proposal: WFII parallel archive proposal

This is the generic target version of the WFPC2 Archival Pure
Parallel program. The program will be used to take parallel images of
random areas of the sky, following the recommendations of the 2002
Parallels Working Group. 

WFPC2 9699

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

 - Continued -

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