Status Report

NASA Hubble Space Telescope Daily Report # 3504

By SpaceRef Editor
December 8, 2003
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S/C/NIC1/NIC3 9994

NICMOS Focus Stability

The purpose of this activity is to determine if the best focus
determined in SMOV is stable. This program will execute in
approximately one month intervals starting about 1 month after the
last execution of proposal 8980.

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


The Ultra Deep Field – STIS parallels

We propose to obtain slitless spectroscopy of objects in the GEMS and
GOODS area around the UDF.

WFPC2 9980

The Ultra Deep Field – WFPC2 Parallels

The ACS Ultra Deep Field {UDF} is a survey carried out by using
Director’s Discretionary time. The main science drivers are galaxy
evolution and cosmology. The primary instrument is the Advanced Camera
for Surveys but WFPC2, NICMOS, and STIS will also be used in pure
parallel mode. The data will be made public. The UDF consists of a
single ultra-deep field {410 orbits in total} within the CDF-S GOODS
area. We request a modification of the default pure parallel programs.
Rather than duplicate the redder bands which will be done much better
with ACS, we propose to observe in the near-ultraviolet F300W filter.
These data will enable study of the rest-frame ultraviolet morphology
of galaxies at 0<z<1, allowing determination of the morphological
k-correction and the location of star formation within galaxies, using
a sample that is likely to be nearly complete with multi-wavelength
photometry and spectroscopic redshifts. The results can be used to
interpret observations of higher redshift galaxies by ACS.

NIC3 9979

The Ultra Deep Field – NICMOS Parallels

This is a plan to manage the NICMOS pure parallels of the ACS Ultra
Deep Survey. We will obtain a mix of F110W and F160W images along
sight-lines within the mosaiced ACS fields of the CDF-S GOODS and GEMS
surveys, with these sight-lines enabling an examination of the space
density and morphologies of the reddest galaxies.


The Ultra Deep Field with ACS

The ACS Ultra Deep Field {UDF} is a survey carried out by using
Director’s Discretionary time. The main science driver are galaxy
evolution and cosmology. The primary instrument is the Advanced Camera
for Surveys but WFPC2 and NICMOS will also be used in parallel. The
data will be made public. The UDF consists of a single ultra-deep
field {410 orbits in total} within the CDF-S GOODS area. The survey
will use four filters: F435W {55 orbits}, F606W {55 orbits}, F775W
{150 orbits}, and F850LP {150 orbits}. The F435W {B} and F606W {V}
exposures will be one magnitude deeper than the equivalent HDF
filters. The F775W {I} exposure will be 1.5 magnitude deeper than the
equivalent HDF exposure. The depth in F775W and F850LP is optimized
for searching very red objects – like z=6 galaxies – at the detection
limit of the F850LP image. The pointing will be RA{J2000}=3 32 40.0
and Decl.{J2000}=-27 48 00. These coordinates may change slightly due
to guide star availability and implementation issues. We will attempt
to include in the field both a spectroscopically confirmed z=5.8
galaxy and a spectroscopically confirmed type Ia SN at z=1.3. The
pointing avoids the gaps with the lowest effective exposure on the
Chandra ACIS image of CDFS. This basic structure of the survey
represents a consensus recommendation of a Scientific Advisory
Committee to the STScI Director Steven Beckwith. A local Working Group
is looking in detail at the implementation of the survey.


Probing the Dynamics and Shock Physics of the Cas A Supernova Remnant

Cassiopeia A {Cas A; SN 1680} is the youngest known and closest
example of an oxygen-rich, core-collapse supernova remnant. A two-year
WFPC2 survey of part of the remnant yielded many new insights
including realization of the stunning amount of fine-scale detail
present in the ejecta, and the first precise location of the reverse
shock front in the main shell via rapid emission and structural
changes visible over 2 yrs. In addition, these data revealed over 100
new ejecta knots located out ahead of the forward blast wave in a
small region where only a handful were known from ground-based images.
We propose a follow-up survey program aimed at obtaining hi-res images
of the entire remnant in the ejecta’s four major emission lines. A
separate set of ACS and NIC3 [Si VI] images of the NW reverse shock
filaments will be taken 3-4 months following the main Cycle 12 survey
images. These will allow us to the trace individual ejecta knot
deceleration dynamics, excitation, and evolution during reverse shock
passage. Analysis of the emission line fluxes will make use of custom
shock models generated by us for Cas A. These data will also provide
data on outer knot chemistry and expansion asymmetries particularly in
regard to the collimation of the NE and SW jets of O, Si, Ca-rich
ejecta. A major aim of this program is to acquire a superb two-year
image database covering the entire remnant to allow a detailed shock
physics and dynamics study.

NIC2 9875

The Fundamental Plane of Massive Gas-Rich Mergers

We propose deep NICMOS H-band imaging of a carefully selected sample
of 33 luminous, late-stage galactic mergers. This program is part of a
comprehensive investigation of the most luminous mergers in the nearby
universe, the ultraluminous infrared galaxies {ULIGs}. The
high-resolution HST images will complement an extensive set of
ground-based data that include long-slit NIR spectra from a recently
approved Large VLT Programme. This unique dataset will allow us to
derive with unprecedented precision structural -and- kinematic
parameters for a large unbiased sample of objects spanning the entire
ULIG luminosity function. These data will refine the fundamental plane
of massive gas-rich mergers and enable us to answer the following
questions: {1} Do ultraluminous mergers form elliptical galaxies, and
in particular, giant ellipticals? {2} Do ULIGs evolve into optically
bright QSOs? The results from this detailed study of massive mergers
in the local universe will be relevant to understanding galaxy
formation and evolution at earlier epochs, and in particular, the
dusty sub-mm population that accounts for more than half of the star
formation at z > 1.


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

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

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.

ACS/WFC 9861

ACS Imaging of beta Pic: Searching for the origin of rings and
asymmetry in planetesimal disks

The emerging picture for planetesimal disks around main sequence stars
is that their radial and azimuthal symmetries are significantly
deformed by the dynamical effects of either planets interior to the
disk, or stellar objects exterior to the disk. The cause of these
structures, such as the 50 AU cutoff of our Kuiper Belt, remains
mysterious. Structure in the beta Pic planetesimal disk could be due
to dynamics controlled by an extrasolar planet, or by the tidal
influence of a more massive object exterior to the disk. The
hypothesis of an extrasolar planet causing the vertical deformation in
the disk predicts a blue color to the disk perpendicular to the disk
midplane. The hypothesis that a stellar perturber deforms the disk
predicts a globally uniform color and the existence of ring-like
structure beyond 800 AU radius. We propose to obtain deep, multi-color
images of the beta Pic disk ansae in the region 15"-220" {200-4000 AU}
radius with the ACS WFC. The unparalleled stability of the HST PSF
means that these data are uniquely capable of delivering the color
sensitivity that can distinguish between the two theories of beta
Pic’s disk structure. Ascertaining the cause of such structure provide
a meaningful context for understanding the dynamical history of our
early solar system, as well as other planetesimal systems imaged
around main sequence stars.

ACS/HRC 9851

Host Galaxies of Reverberation-Mapped AGNs

We propose to obtain unsaturated ACS high-resolution images of all
reverberation-mapped active galactic nuclei in order to remove the
point-like nuclear light from each image, thus yielding a
"nucleus-free" image of the host galaxy. This will allow investigation
of host-galaxy properties: our particular interest is determination of
the host-galaxy starlight contribution to the reverberation mapping
observations, which is necessary for accurate determination of the
relationship between the AGN continuum flux and the size of the broad
Balmer-line emitting region of AGNs. Because this relationship is used
to estimate black-hole masses of large samples of distant AGNs,
correct determination of the slope of this relationship is critically


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}.

WFPC2 9809

Saturn’s rings and small moons on the eve of Cassini

We propose to continue our long-term survey of Saturn’s rings and
small moons to obtain a coherent set of high resolution, multi-color
WFPC2 images of Saturn and its rings during the final year before the
arrival of the Cassini spacecraft at Saturn in mid-2004. Our Cycle
6-11 programs {6806, 7427, 8398, 8660, 8802, and 9341} explored the
rings from their nearly edge-on aspect {southern hemisphere spring} to
summer solstice in late 2002. We now propose to take advantage of the
especially favorable viewing geometry of Cycle 12 to obtain UBVRI,
F255W, and methane-filter PC images of the rings, small moons, and
planet at the lowest phase angle {0.07 degrees} observable to date. A
key goal is to measure for the first time the expected sharp spike in
the opposition brightness of the rings and small moons, which will
characterize the structure and particle properties of the rings and
the surfaces of the satellites. We will also follow the chaotic
behavior of Prometheus and Pandora, two small moons which may be
perturbing each other gravitationally. Here, our goals are to catch
the satellites in the act of any new coupled motions and to determine
the changes in semimajor axis, eccentricity, and orbital inclination
of the moons resulting from their most recent large chaotic
interaction in 2000. This will complete our continuous WFPC2 coverage
of these moons from 1994 until mid-2004, when Cassini’s cameras will
at long last surpass the capabilities of the HST. The Cycle 12
observations will also enable us to determine zonal winds and regional
variations in Saturn’s atmosphere prior to Cassini’s arrival.


The Grism-ACS Program for Extragalactic Science {GRAPES}

We propose an ACS grism spectroscopic survey with a wide component and
an ultradeep single ACS field. The wide component covers the
well-imaged GOODS Chandra Deep Field south and the deepest field will
be the Ultra Deep field to be observed in cycles 11 and 12. The Grism
ACS Program for Extra-galactic Science {GRAPES} will: {1} Probe the
reionization epoch by robustly determining the luminosity function of
Lyman-alpha emitters, Lyman break galaxies and low luminosity AGNs at
z~6, and thus the sources of ionizing photons at the end of the "dark
ages". A similar census of ionizing photon sources at z=4-6 needed to
maintain the ionized state of the IGM will also be achieved. {2} Study
galaxy formation and evolution by finding galaxies in a contiguous
redshift range between z=4-7 and evolution of black holes through a
census of low-luminosity AGNs. {3} Study star-formation and galaxy
assembly at its peak at z=1-2 by identifying star-forming galaxies by
their emission lines, old galaxies by the 4000 AA break and any
combination of new and old populations showing both lines and breaks.
{4} Allow the deepest unbiased spectroscopy yet, for identification of
objects to I=27. {5} Enhance the value of multiwavelength data in the
UDF and GOODS field to the astronomical community.

WFPC2 9712

Pure Parallel Near-UV Observations with WFPC2 within High-Latitude ACS
Survey Fields

In anticipation of the allocation of ACS high-latitude imaging
survey{s}, we request a modification of the default pure parallel
program for those WFPC2 parallels that fall within the ACS survey
field. Rather than duplicate the red bands which will be done much
better with ACS, we propose to observe in the near-ultraviolet F300W
filter. These data will enable study of the rest-frame ultraviolet
morphology of galaxies at 0<z<1. We will determine the morphological
k-correction, and the location of star formation within galaxies,
using a sample that is likely to be nearly complete with
multi-wavelength photometry and spectroscopic redshifts. The results
can be used to interpret observations of higher redshift galaxies by

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.


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.

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


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.

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 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 10000

STIS Pure Parallel Imaging Program: Cycle 12

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


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

HSTAR 9227: While guiding on two FGSs, after successful GS
Acquisition (2,1,2) @ 339/13:46:40Z, LOL occurred @ 339/13:59:47Z due
to SSLE on FGS 1, followed by new sequential update (#44 Command) @
339/14:00:40Z. Spacecraft was successfully guiding on two FGS in
spite of this event. FHST Map @ 339/13:54:56Z had large roll error,
V1 = 109.467 arcsec, 3-axis error (RSS). Under investigation.

HSTAR 9228: GS Acquisition (2,1,2) @ 339/15:22:45Z, which began
during ZOE, resulted in FL backup at AOS, without indication flags,
using FGS 2 (2,0,2). Unable to determine FGS modes and Flag Bit
changes, pending SSR dump @ 340/00:50:45Z. FHST Map @ 339/15:31:01Z
showed vehicle axis errors V1 = -154.931, V2 = -4.564, V3 = 9.748
arcsec. From SSR dump, analysis indicates GS Acquisition failed due
to SSLE @ 339/15:26:25Z. Under investigation.

HSTAR 9229: GS Acquisition (2,1,2) @ 339/16:58:50Z resulted in FL
back (2,0,2) using FGS 2 due to SSLE on FGS 2. FHST Map @
339/17:07:06Z showed vehicle axis errors V1 = -157.647, V2 = -6.698,
V3 = 3.693 arcsec. Under investigation.

HSTAR 9233: GS Acquisition (1,2,1) @ 342/02:25:24Z resulted in FL
backup due to SSLE on FGS 2. GS Re-acquisitions @ 342/04:02:04Z and
05:38:07Z will also result in FL backup. Under investigation.



                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq               25                        25
FGS REacq               19                        19
FHST Update             41                        41


SpaceRef staff editor.