Status Report

NASA Hubble Space Telescope Daily Report #3516

By SpaceRef Editor
December 29, 2003
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HUBBLE SPACE TELESCOPE

DAILY REPORT # 3516

PERIOD COVERED: DOY 357

OBSERVATIONS SCHEDULED

ACS 9984

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.

ACS/HRC/WFC 10042

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.

ACS/WFC/WFPC2 9810

Accurate and Robust Calibration of the Extragalactic Distance Scale
with the Maser Galaxy NGC4258

The extragalactic distance scale {EDS} is defined by a comparison of
Cepheid Period-Luminosity {PL} relations for nearby galaxies and the
LMC, whose uncertain distance is thereby the SOLE anchor. Studies of
maser sources orbiting the central black hole in the galaxy NGC4258
have provided the most accurate extragalactic distance ever {7.2+/-
0.5Mpc}. Since this distance is well determined and based on GEOMETRIC
arguments, NGC4258 can provide a much needed new anchor for the EDS.
We propose multi-epoch BVIH observations of NGC4258 in order to
discover about 100 Cepheids and to characterize their light curves
with 2-3 times greater accuracy than was previously possible with
WFPC2. At 90 orbits {48 in Cycle 12; 42 in Cycle 13}, this is a
relatively large program. However, the result will have a major impact
on the EDS, and substantial attention must be paid to characterization
and minimization of systematic errors, as from metallicity, crowding,
and blending. The resulting dataset will be the most complete for
Cepheids in any galaxy yet studied with HST. In an ongoing NASA-funded
program {OSS-SARA}, we are using new analysis techniques and radio
data to reduce uncertainty in the geometric distance to < 3% {0.07
mag}. With this improved geometric distance and the BVIH data, we will
be able to calculate the zero point of the PL relation ROBUSTLY to <4%
{0.09 mag}.

ACS/WFC/WFPC2 9822

The COSMOS 2-Degree ACS Survey

We will undertake a 2 square degree imaging survey {Cosmic Evolution
Survey — COSMOS} with ACS in the I {F814W} band of the VIMOS
equatorial field. This wide field survey is essential to understand
the interplay between Large Scale Structure {LSS} evolution and the
formation of galaxies, dark matter and AGNs and is the one region of
parameter space completely unexplored at present by HST. The
equatorial field was selected for its accessibility to all
ground-based telescopes and low IR background and because it will
eventually contain ~100, 000 galaxy spectra from the VLT-VIMOS
instrument. The imaging will detect over 2 million objects with I> 27
mag {AB, 10 sigma}, over 35, 000 Lyman Break Galaxies {LBGs} and
extremely red galaxies out to z ~ 5. COSMOS is the only HST project
specifically designed to probe the formation and evolution of
structures ranging from galaxies up to Coma-size clusters in the epoch
of peak galaxy, AGN, star and cluster formation {z ~0.5 to 3}. The
size of the largest structures necessitate the 2 degree field. Our
team is committed to the assembly of several public ancillary datasets
including the optical spectra, deep XMM and VLA imaging, ground-based
optical/IR imaging, UV imaging from GALEX and IR data from SIRTF.
Combining the full-spectrum multiwavelength imaging and spectroscopic
coverage with ACS sub-kpc resolution, COSMOS will be Hubble’s ultimate
legacy for understanding the evolution of both the visible and dark
universe.

FGS 10010

Long Term Monitoring of FGS1r in Position Mode

It is known from our experience with FGS3, and later with FGS1r, that
an FGS on orbit experiences long term evolution, presumably due to
disorption of water from the instrument’s graphite epoxy composites.
This manifests principally as a change in the plate scale and
secondarily as a change in the geometric distortions. These effects
are well modeled by adjustments to the rhoA and kA parameters which
are used to transform the star selector servo angles into FGS {x, y}
detector space coordinates. By observing the relative positions of
selected stars in a standard cluster at a fixed telescope pointing and
orientation, the evolution of rhoA and kA can be monitored and
calibrated to preserve the astrometric performance of FGS1r.

FGS 10012

F583W/F5ND Cross Filter Calibration FGS1r Off Center

This proposal calibrates the shift of a star’s position when observed
through the F550 filter and F5ND attenuator relative to the F583W
filter at locations off center in the FGS1r FOV. This calibration is
necessary to support ongoing multi-cycle FGS astrometry proposals
{extrasolar planet astrometry and the Cepheid distance scale in
particular}.

FGS 9335

Masses of Pre-Main Sequence Binaries

We propose to continue to map the orbits of young star binaries in the
Taurus and Ophiuchus star forming regions. Our goal is to measure
their masses dynamically. This is important because there are still no
low mass young stars with reliably known masses so calculations of
their evolution to the main sequence are uncalibrated.

FGS 9879

An Astrometric Calibration of the Cepheid Period-Luminosity Relation

We propose to measure the parallaxes of 10 Galactic Cepheid variables.
There is no other instrument on or off the earth that can consistently
deliver HST FGS level of precision for critical parallaxes. When these
parallaxes {with 1-sigma precisions of 10% or better} are added to our
recent HST FGS parallax determination of delta Cep {Benedict et al
2002}, we anticipate determining the Period-Luminosity relation zero
point with a 0.03 mag precision. In addition to permitting the test of
assumptions that enter into other Cepheid distance determination
techniques, this calibration will reintroduce Galactic Cepheids as a
fundamental step in the extragalactic distance scale ladder. A
Period-Luminosity relation derived from solar metallicity Cepheids can
be applied directly to extragalactic solar metallicity Cepheids,
removing the need to bridge with the Large Magellanic Cloud and its
associated metallicity complications.

NIC/NIC3 9865

The NICMOS Parallel Observing Program

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7<z<1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial–but poorly observed–redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

NIC1 9749

NICMOS Observations of the Gl 164 Companion

We propose to image an astrometrically-detected companion of Gl 164.
The companion was discovered with the Stellar Planet Survey {STEPS}
instrument operating on the Palomar 200" telescope. The mass of the
companion is estimated to be ~40 Jupiter masses or more placing it in
the brown dwarf range. If we can detect this companion with NICMOS and
confirm its nature, we will have one of the few direct measurements of
the mass of a brown dwarf.

NIC3 9999

The COSMOS 2-Degree ACS Survey NICMOS Parallels

The COSMOS 2-Degree ACS Survey NICMOS Parallels. This program is a
companion to program 9822.

NICMOS 8790

NICMOS Post-SAA calibration – CR Persistence Part 1.

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.

STIS 10033

MAMA Sensitivity and Focus Monitor Cycle 12

Monitor sensitivity of each MAMA grating mode to detect any change due
to contamination or other causes. Also monitor the STIS focus in a
spectroscopic and an imaging mode.

STIS 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.

STIS/CCD 10000

STIS Pure Parallel Imaging Program: Cycle 12

This is the default archival pure parallel program for STIS during
cycle 12.

STIS/CCD 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 10019

CCD Bias Monitor – Part 1

Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1,
and 1×1 at gain = 4, to build up high-S/N superbiases and track the
evolution of hot columns.

STIS/CCD 10023

STIS CCD Spectroscopic Flats C12

Obtain CCD flats on the STIS CCD in spectroscopic mode

STIS/CCD 10024

STIS CCD Imaging Flats C12

Investigate flat-field stability over a bimonthly period.

STIS/CCD 10085

STIS Pure Parallel Imaging Program: Cycle 12

This is the default archival pure parallel program for STIS during
cycle 12.

STIS/CCD 9866

First Spectroscopic Study of a Unique Set of Young Stars in the Orion
Nebula

We propose to obtain the first spectra of the central stars of Orion
proplyds for which the stars are visible in WFPC images. While it is
known that the central stars are broadly late-type, they have never
been spectrally classified or studied in detail as pre-MS objects. The
Orion proplyds are generally thought to be protoplanetary disks
similar to the primordial disk of the Solar System. They offer a
unique opportunity to understand the physical conditions of
protoplanetary disks in a nebular environment generally believed to be
typical of that in which most stars formed. Models of the proplyds are
available which predict the observable IR spectral energy distribution
using the spectral type of the central star as part of the numerical
input. Further progress in understanding proplyds will require
knowledge of the spectral types of these stars. We will use
already-proven diagnostics for spectrally classifying late-type PMS
stars. In addition, many emission lines are expected in objects of
this age which can be used to look for infall and outflow. Different
accretion models of young stars predict different line widths, so our
observations can help test models of late-type pre-MS stars and can be
used to compare as pre-MS objects the proplyd stars with other pre-MS
stars.

STIS/MA1 10034

Cycle 12 MAMA Dark Monitor

This test performs the routine monitoring of the MAMA detector dark
noise. This proposal will provide the primary means of checking on
health of the MAMA detectors systems through frequent monitoring of
the background count rate. The purpose is to look for evidence of
change in dark indicative of detector problem developing.

WFPC2 10069

WFPC2 CYCLE 12 Supplemental Darks, Part 1/3

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

WFPC2 9709

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.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTAR 9249: Scattered light has appeared in a number of ACS observations,
as follows:

  • 2003 11 11 14 04 08 j8hqe9opq 9468 CLEAR 1L F814W
  • 2003 11 11 14 15 14 j8hqe9osq 9468 CLEAR 1L F814W
  • 2003 11 11 22 01 19 j8qu04q1q 9722 CLEAR 1L F814W
  • 2003 11 11 22 14 55 j8qu04q6q 9722 CLEAR 1L F814W
  • 2003 11 11 22 28 31 j8qu04qaq 9722 CLEAR 1L F814W

Further analysis will determine if repeat observations are required.

COMPLETED OPS REQs: None

OPS NOTES EXECUTED: 1181-2 Raise Battery 3 red temp to safety limit

                             SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                 08                        08
FGS REacq                 05                        05
FHST Update               21                        21
LOSS of LOCK

SIGNIFICANT EVENTS: None

SpaceRef staff editor.