NASA Hubble Space Telescope Daily Report # 3528
HUBBLE SPACE TELESCOPE
DAILY REPORT # 3528
PERIOD COVERED: DOYs 9-11/2004
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.
STIS/CCD 9981
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.
ACS/CCD/WFC 9978
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.
FGS 9969
FGS Astrometry of the Extrasolar Planet of Epsilon Eridani
We propose observations with HST/FGS in Position Mode to determine the
astrometric elements {perturbation orbit semimajor axis and inclination} of the
candidate extra-solar planet around the K2 V star Epsilon Eridani that has been
detected by Doppler spectroscopy. These observations will also permit us to
determine the actual mass of the planet by providing the sin{i} factor
which can
not be determined with the radial velocity method. High precision radial
velocity {RV} measurements spanning the years 1980.8–2000.0 for the nearby
{3.22 pc} star Epsilon Eri show convincing variations with a period of ~ 7 yrs.
These data represent a combination of six independent data sets taken with four
different telescopes. A least squares orbital solution using robust estimation
yields orbital parameters of period, P = 6.9 yrs, velocity K- amplitude = 19
m/s, eccentricity e = 0.6, projected companion mass M_B sin{i} = 0.83
M_Jupiter.
An estimate of the inclination yields a perturbation semi-major axis, Alpha =
0arcs0022, easily within the reach of HST/FGS astrometry.
ACS/HRC/WFC 9919
The Morphological, Photometric, and Spectroscopic Properties of Intermediate
Redshift Cluster Galaxies:
New and fundamental constraints on the evolutionary state of high redshift
clusters will be made by obtaining deep, multiband images {SDSS r, i, z} over
the central 1.5 Mpc regions of seven distant clusters in the range 0.76 < z <
1.27. The ACS data will allow us to {1} definitively establish the
morphological
composition and star formation rates as functions of clustercentric radius,
local density, x-ray luminosity {obtained from accompanying Chandra, and XMM
data}, {2} explore the relationship between substructure, kinematics, and
morphology, {3} strongly constrain the galaxy merger frequency and the origins
of elliptical and S0 galaxies, {4} measure the mass distribution independently
from the light {via gravitational lensing} enabling comparisons with
kinematically derived masses, and {5} study the evolution of the structure of
the brightest cluster members. The clusters selected for this program already
have extensive spectroscopic observations and NIR imaging is either in hand or
underway from approved ground based programs. To date, the lower part of this
redshift range has only been marginally studied with HST. Our sample includes
the two most distant, spectroscopically confirmed superclusters and will
significantly increase the baseline over which evolutionary effects can be
studied. The data will also be used to identify very high-z galaxies via their
unique spectral properties.
FGS 9882
The Distance and Mass of the Neutrino-Luminous White Dwarf PG 0122+200
PG 0122+200 is a pulsating hot white dwarf that is believed to radiate more
energy as neutrinos than it does as photons. We propose to measure with FGS the
trigonometric parallax of PG 0122+200 and thereby determine its distance,
luminosity, and mass. Ongoing investigations from the ground will infer the
neutrino luminosity through its effect on the pulsation periods, thus testing
standard and non-standard lepton theory, but the stellar mass must first be
known. The pulsation spectrum of PG 0122+200 admits two alternative
seismological interpretations, each implying a different mass, luminosity, and
distance. Measurement of an accurate distance will resolve the matter once and
for all and precisely determine the stellar mass. This project represents the
first test of lepton physics in dense {log rho = 6} plasma and is relevant to
the many areas of stellar physics in which neutrino interactions are important,
including recent theories intended to solve the solar-neutrino problem.
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 9860
ESSENCE: Measuring the Dark Energy Equation of State
The accelerating universe appears to be dominated by a dark energy with a
significant negative pressure. The ratio of the pressure to density of this
mysterious energy {its equation of state} is an observable which can
differentiate between the proliferating candidate theories. We propose to
estimate the dark energy equation of state by observing Type Ia supernovae at
redshifts near z=0.7 with HST in concert with the on-going ESSENCE NOAO Survey
program that is discovering and studying supernovae between 0.3<z<0.8. We show
that an interesting constraint on the equation of state can be made with
supernovae observed at modest redshifts given the current knowledge of the
matter density. We will follow 10 Type Ia supernovae discovered from the ground
and passed to HST without disrupting its schedule. The full data set will
constrain the equation of state to 10% and strictly limit the range of possible
dark energy models. In keeping with the ESSENCE policy, these observations will
available to the community immediately.
ACS/WFC/WFPC2 9825
An ACS/WFC H-alpha Survey of the Orion Nebula
We propose to survey nearly 500 square arcminutes of the Orion Nebula in
H-alpha
using the ACS/WFC, increasing the sky coverage by an order of magnitude
over the
sum of all previous HST observations. This survey will, for the first time,
sample the majority of young stars and circumstellar environments in the
extended Trapezium cluster of 2, 000 low-mass stars. Our primary goal is to
determine the survival rate and statistical properties of protoplanetary disks
in the type of radiation field and dynamical environment in which most
stars are
born. The survey will be used to search for new silhouette disks, bright
proplyds, microjets, large-scale outflows, and to characterize the
properties of
these objects as a function of location in the nebula. We will determine
accurate proper motions in regions where previous HST data exist. However, 90%
of our fields will be observed with HST for the first time. This survey will
provide the first complete census of pre-main sequence objects and outflows in
an HII region and will constrain the extent of hazards to planet formation in
such environments. The images will also provide a legacy for future stellar and
nebular variability studies and proper motion measurements by providing a first
epoch data base.
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 9783
The Ages of Nuclear Star Clusters in Early-type Spiral Galaxies
We propose to obtain STIS G430L spectra of the previously identified nuclear
star cluster in a sample of 16 spiral galaxies of early to intermediate Hubble
type. HST’s spatial resolution is required to separate the nuclear cluster from
the underlying galaxy bulge. Analysis of the spectra with population synthesis
methods will reveal the cluster ages. We will use the age distribution to
constrain the duty cycle of nuclear cluster formation. Comparison of the
results
to those for a larger sample of nuclear clusters in late-type, bulgeless
galaxies will allow us to investigate possible differences between the
formation
mechanisms of nuclear clusters in early and late Hubble types. Such differences
might be expected because galaxy bulges show a dichotomy: in late Hubble types,
the surface brightness profiles are best described by an exponential, while
they
follow a de Vaucouleurs law in earlier types. Although the reason for this
dichotomy is still unknown, it is plausible that galaxy bulges have different
formation mechanisms at the two ends of the Hubble sequence. We know that {1}
nuclear cluster formation is linked to the funneling of gas towards the nucleus
via gravitational torques from stellar bars, {2} a nuclear mass concentration
can make bars unstable, and {3} unstable bars can form bulges. Therefore, the
age distribution of nuclear star clusters contains important clues to the
evolution of galaxy centers and promises new insight into the origin of the
Hubble sequence.
ACS/WFC/HRC 9771
The local Hubble flow and the density field within 6 Mpc
Great progress has been made recently in accurate distance measurements of
nearby galaxies beyond the Local Group based on the luminosity of the tip
of the
red giant branch {TRGB}. Over the last three years, snapshot surveys with HST
have provided us with the TRGB distances for more than a hundred nearby
galaxies
obtained with an accuracy of about 10%. The local velocity field within 5 Mpc
exhibits a significant anisotropy which disagrees with a spherical
Virgo-centric
flow. The local Hubble flow is very cold, with 1-D rms deviations of ~30 km/s.
Cosmological simulations with Cold Dark Matter can only realize such low
dispersions with a combination of a low mean density of matter and a
substantial
component with negative pressure. There may be a constraint on the equation of
state w=-p/rho. Our observations will concentrate on 116 galaxies whose
expected
distances lie within 4 – 6 Mpc, allowing us to trace a Dark Matter distribution
in the Local Volume with twice the information currently available. The program
is a good one for SNAP mode because the order and rate that the
observations are
made are not very important, as long as there is good completion over several
years.
STIS/CCD/MA1 9759
Confirmation of New Candidates for the Study of Intergalactic Helium
The reionization of intergalactic helium is believed to take place between
redshift 3 and 4. The study of HeII Lyman-alpha absorption in four quasars at
2.7<z<3.3 demonstrates the great potential of such an intergalactic-medium
{IGM}
probe and suggests that the reionization epoch is at higher redshifts. Clean
quasar sightlines may be found only from massive pre-selection processes in the
optical and UV, because of random, severe absorption by intervening Lyman-limit
systems. The SDSS has discovered approximately 36000 quasars, and we propose to
verify the UV detectability in 70 top candidates for helium studies
extending to
even higher redshift. Our proposed approach has already proven successful, and
additional positive confirmations will allow follow-up observations, with STIS
or COS, to pinpoint the epoch of reionization of the IGM, and the evolution of
its properties near that period.
ACS/HRC 9747
An Imaging Survey of the Statistical Frequency of Binaries Among
Exceptionally-Young Dynamical Families in the Main Asteroid Belt
We propose an ambitious SNAPSHOT program to determine the frequency of binaries
among two very young asteroid families in the Main Belt, with potentially
profound implications. These families {of C- and S-type} have recently been
discovered {Nesvorny et al. 2002, Nature 417, 720}, through dynamical modeling,
to have been formed at 5.8 MY and 8.3 MY ago in catastrophic impact events.
This
is the first time such precise and young ages have been assigned to a family.
Main-belt binaries are almost certainly produced by collisions, and we would
expect a young family to have a significantly higher frequency of binaries than
the background, because they may not yet have been destroyed by impact or
longer-term gravitational instabilities. In fact, one of the prime observables
from such an event should be the propensity for satellites. This is the
best way
that new numerical models for binary production by collisions {motivated
largely
by our ground-based discoveries of satellites among larger asteroids}, can be
validated and calibrated. HST is the only facility that can be used to search
for binaries among such faint objects {V>17.5}. We will also measure two
control
clusters, one being an "old" family, and the other a collection of background
asteroids that do not have a family association, and further compare with our
determined value for the frequency of large main-belt binaries {2%}. We request
visits to 180 targets, using ACS/HRC.
ACS/WFC 9744
HST Imaging of Gravitational Lenses
Gravitational lenses offer unique opportunities to study cosmology, dark
matter,
galactic structure, galaxy evolution and quasar host galaxies. They are
also the
only sample of galaxies selected based on their mass rather than their
luminosity or surface brightness. While gravitational lenses can be discovered
with ground-based optical and radio observations, converting them into
astrophysical tools requires HST. HST has demonstrated that it is the only
telescope that can in each case precisely locate the lens galaxy, measure its
luminosity, color and structure, and search for lensed images of the source
host
galaxy given the typical image separations of ~1”. We will obtain ACS/WFC
V and
I images and NICMOS H images of 21 new lenses never observed by HST and
NICMOS H
images of 16 lenses never observed by HST in the IR. As in previous cycles, we
request that the data be made public immediately.
NIC2 9726
A NICMOS search for obscured supernovae in starburst galaxies
Recent near-IR monitoring campaigns were successful in detecting obscured
supernovae {SNe} in starburst galaxies. The inferred SN rate is much higher
than
that obtained in previous optical campaigns, but it is still significantly
lower
than expected by the high level star formation of these systems. One possible
explanation for the shortage of SNe is that most of them occur in the nuclear
region, where the limited angular resolution of groundbased observations
prevents their detection. We propose NICMOS SNAP observations of a sample of
starburst galaxies already observed once by NICMOS, with the goal of exploiting
its sensitivity and angular resolution to detect nuclear obscured SNe which
might have been missed by groundbased surveys. These observation will allow to
assess the real SN rate in starbust galaxies and deliver a sample of SN
occurring in the extreme environment of galactic nuclei. We expect to detect
more than 55 SNe {if the whole sample is observed}. If the number of SNe
detected in the program is much lower than expected it would prompt for a
revision of our understanding of the relation between the star formation rate
and the SN rate.
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.
STIS 9633
STIS parallel archive proposal – Nearby Galaxies – Imaging and Spectroscopy
Using parallel opportunities with STIS which were not allocated by the TAC, we
propose to obtain deep STIS imagery with both the Clear {50CCD} and Long-Pass
{F28X50LP} filters in order to make color-magnitude diagrams and luminosity
functions for nearby galaxies. For local group galaxies, we also include G750L
slitless spectroscopy to search for e.g., Carbon stars, late M giants and
S-type
stars. This survey will be useful to study the star formation histories,
chemical evolution, and distances to these galaxies. These data will be placed
immediately into the Hubble Data Archive.
ACS/STIS 9451
ACS Imaging and STIS Spectroscopy of Binary Brown Dwarfs
We have compiled a sample of 9 spatially resolved binary brown dwarfs {18
objects}, and now propose ACS imaging and STIS spectroscopic follow-up
observations. While theoretical models on the interplay of chemical and
physical
processes governing brown dwarf atmospheres have reached a high level of
sophistication, interpretation of observational data remains difficult. As
brown
dwarfs never stabilize themselves on the hydrogen main sequence, there is
always
an ambiguity between the temperature or luminosity of any brown dwarf and its
mass or age. The individual components of brown dwarf binaries, however, are
expected to be coeval and have the same underlying chemical composition. This
provides crucial constraints on any model, thus greatly reducing the number of
the free parameters. The aim is to obtain photometric and spectroscopic data to
probe the physical and chemical properties of the brown dwarf atmospheres, as
well as second epoch astrometric data to characterize th e orbital motion. The
study will provide important feedback on theoretical model atmospheres and
evolutionary tracks for brown dwarfs. As such, it will be an important step
towards a better understanding of objects with spectral properties intermediate
between those of giant planets and late-type stars.
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.
STIS/CCD 10085
STIS Pure Parallel Imaging Program: Cycle 12
This is the default archival pure parallel program for STIS during cycle 12.
STIS/MA1 10083
HST UV Images of Saturn’s Aurora Coordinated with Cassini Solar Wind
Measurements
A key measurement goal of the Cassini mission to Saturn is to obtain
simultaneous solar wind and auroral imaging measurements in a campaign
scheduled
for Jan. 2004. Cassini will measure the solar wind approaching Saturn
continuously from 9 Jan. – 6 Feb., but not closer to Saturn due to competing
spacecraft orientation constraints. The only system capable of imaging Saturn’s
aurora in early 2004 will be HST. In this community DD proposal we request the
minimum HST time needed to support the Cassini mission during the solar wind
campaign with UV images of Saturn’s aurora. Saturn’s magnetosphere is
intermediate between the "closed" Jovian case with large internal sources of
plasma and the Earth’s magnetosphere which is open to solar wind interactions.
Saturn’s aurora has been shown to exhibit large temporal variations in
brightness and morphology from Voyager and HST observations. Changes of auroral
emitted power exceeding one order of magnitude, dawn brightenings, and
latitudinal motions of the main oval have all been observed. Lacking knowledge
of solar wind conditions near Saturn, it has not been possible to determine its
role in Saturn’s auroral processes, nor the mechanisms controlling the auroral
precipitation. During Cassini’s upcoming approach to Saturn there will be a
unique opportunity to answer these questions. We propose to image one complete
rotation of Saturn to determine the corotational and longitudinal
dependences of
the auroral activity. We will then image the active sector of Saturn once every
two days for a total coverage of 26 days during the Cassini campaign to measure
the upstream solar wind parameters. This is the minimum coverage needed to
ensure observations of the aurora under solar wind pressure variations of more
than a factor of two, based on the solar wind pressure variations measured by
Voyager 2 near Saturn on the declining phase of solar activity. The team of
proposers has carried out a similar coordinated observing campaign of Jupiter
during the Cassini flyby, resulting in a set of papers and HST images on the
cover of Nature on 28 February 2002.
WFPC2 10082
POMS Test Proposal: WFII backup parallel archive proposal
This is a POMS test proposal designed to simulate scientific plans
WFPC2 10076
WFPC2 Cycle 12 CTE Monitor
Monitor CTE changes during Cycle 12, including 2X2 binning characterization.
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.
ACS/HRC/WFC 10059
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.
NIC3 10014
Spectrophotometry of FAINT IR STANDARDS
Faint spectrophotometric standard stars required for COS and the SBC channel on
ACS have been established via the STIS FASTEX program that has executed
over the
last three cycles. Cycle 12 is an especially opportune time to establish
companion faint IR standards for WFC3, because the NICMOS proposal 9998
includes
observations in cycle 12 of all 6 of the primary standard stars in order to
establish the absolute flux calibration of the three grism modes to 1%. In
addition to WFC3, these new faint secondary IR standards will be a significant
step towards establishing flux standards for JWST, as well as for SNAP, SIRTF,
and SOFIA. The 6 primary standards included in Propid=9998 are in the range of
V=11-13 and include three hot pure hydrogen WDs and 3 solar analogs. We propose
to establish new IR faint standards in the 15-17 mag range. Appropriate
spectral
types for faint IR standards are solar analogs and hotter WDs. Many M type and
cooler stars are variable, so that long term monitoring is required before
committing HST time to such cool stars. A few G type and WD faint stars will
provide a set of faint IR standards with minimal sky and color coverage.
Existing HST images of any candidates can provide verification that there
are no
contaminating stars above the 1% level within 2-3arcsec. However, the ACS
calibration field in 47 Tuc is too crowded for linking to ground based
observations. If the other candidates are selected from SDSS or other ground
based data, then the NICMOS and STIS acquisition images can provide this
verification, as well as correction factors for arbitrary photometric size
apertures. The SNAP team is providing the northern faint stars using unreleased
SDSS data. In addition, the extreme coolest types such as L and T stars have
proven essential to sorting out the long wavelength QE of ACS; both the ACS and
eventually WFC3 calibrations could be improved with knowledge of L and T
SEDs in
the region beyond 0.95 microns. In addition to the primary purpose of ACS
QE vs.
wavelength and broad band F814W and F850LP calibrations, these three stars in
C.} below are at the flux level required for WFC3 grism calibration. The
brighter M, L, and T standard stars will each require a NICMOS orbit, while
each
faint standard requires two Nicmos orbits and one STIS orbit for complete
wavelength coverage. The STIS spectra of the M and L stars are done as ACS
calibrations in cycles 12 and 11, respectively. An additional faint WD has
already been proposed for 2 Nicmos and 4 STIS orbits in their cycle 12 programs
already. See Table 1 for a summary of the 18 orbit allocation for this program
10014. Bright stars in the V=0-6 mag range would be useful for direct
comparisons to NIST calibrated lamps. This comparison would offer the
opportunity to compare two fundamentally different realms of physics: pure
hydrogen stellar models and laboratory black body physics. Unfortunately, the
Nicmos bright limit is V=~8 for a solar analog and a 1s exposure without
defocussing the OTA. The primary Sloan standard BD+17d4708 at V=9.9 is safely
fainter than this Nicmos limit.
WFPC2/ACS/HRC/WFC 10013
Focus Monitor
The focus of HST is measured from WFPC2/PC and ACS/HRC images of stars.
Multiple
exposures are taken in parallel over an orbit to determine the influence of
breathing on the derived mean focus. Observations are taken of clusters with
suitable orientations to ensure stars appear in all fields.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.)
HSTAR 9274: GS Re-acquisition (2,3,2) @ 009/20:23:56Z (during LOS)
resulted in FL
backup FGS2 due to SSLEX on FGS 3. Following FHST
Map scheduled for
the time 009/21:22Z showed attitude error of 1.104,
0.632, and 1.595
arcsec. Following GS re-acquisition @ 009/22:03:43Z
passed with FL.
Under investigation.
HSTAR 9275: GS Acquisition (1,2,2) @ 010/04:13:51Z resulted in FL backup
FGS 1 due
to SSLE on FGS 2. Prior FM Updates @ 010/03:56Z and
03:59Z showed good
attitude error vector. Under investigation.
HSTAR 9276: GS Acquisition (1,2,2) @ 010/15:24:57Z resulted in FL backup
using FGS
1 due to SSLE on FGS 2. Under investigation.
HSTAR 9277: FHST FM Update and GS Acquisition Failure @ 011/20:25:43Z and
20:28:28Z
failed with Error Box results showing "3 FAILED" for
mnemonics QEBSTFG0,
QEBSTFG1, and QEBSTFG2. GS Acquisition (1,3,1)
failed due to radius
limit exceeded on FGS 1. Under investigation.
HSTAR 9278: FHST Roll Delay Update failure @ 011/21:59:10Z. Error Box
results QEBSTF0,
QEBSTFG1, and QEBSTFG2 showed "3 FAILED". Under
investigation.
COMPLETED OPS REQs: NONE
OPS NOTES EXECUTED: NONE
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 28 27 See HSTAR # 9277
FGS REacq 17 17
FHST Update 72 69 See HSTAR #
9277 & 9278
LOSS of LOCK
SIGNIFICANT EVENTS: None
